4841E–WIRE–03/12
Features
●Multi channel half-duplex transceiver with approximately ±2.5MHz programmable
tuning range
●High FSK sensitivity: –106dBm at 20Kbit/s/–109.5dBm at 2.4Kbit/s (433.92MHz)
●High ASK sensitivity: –112.5dBm at 10Kbit/s/–116.5dBm at 2.4Kbit/s (433.92MHz)
●Low supply current: 10.5mA in RX and TX Mode (3V/TX with 5dBm)
●Data Rate: 1 to 20Kbit/s Manchester FSK, 1 to 10Kbit/s Manchester ASK
●ASK/FSK receiver uses a low-IF architecture with high selectivity, blocking, and low
intermodulation (typical blocking 55dB at ±750kHz/61dB at ±1.5MHz and
70dB at ±10MHz, system I1dBCP = –30dBm/system IIP3 = –20dBm)
●226kHz/237kHz IF frequency with 30dB image rejection and 170kHz usable IF
bandwidth
●Transmitter uses closed loop fractional-N synthesizer for FSK modulation with a
high PLL bandwidth and an excellent isolation between PLL/VCO and PA
●Tolerances of XTAL compensated by fractional-N synthesizer with 800Hz RF
resolution
●Integrated RX/TX-switch, single-ended RF input and output
●RSSI (Received Signal Strength Indicator)
●Communication to microcontroller with SPI interface working at max.500kBit/s
●Configurable self polling and RX/TX protocol handling with FIFO-RAM buffering of
received and transmitted data
●Five push button inputs and one wake-up input are active in power-down mode
●integrated XTAL capacitors
●PA efficiency: up to 38% (433.92MHz/10dBm/3V)
●Low in-band sensitivity change of typically ±1.8dB within ±58kHz center frequency
change in the complete temperature and supply voltage range
●Supply voltage switch, supply voltage regulator, reset generation, clock/interrupt
generation and low battery indicator for microcontroller
Atmel ATA5428
UHF ASK/FSK Transceiver
DATASHEET
2Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
●Fully integrated PLL with low phase noise VCO, PLL loop filter and full support of multi-channel operation with arbitrary
channel distance due to fractional-N synthesizer
●Sophisticated threshold control and quasi-peak detector circuit in the data slicer
●Power management via different operation modes
●433.92MHz and 868.3MHz without external VCO and PLL components
●Inductive supply with voltage regulator if battery is empty (AUX mode)
●Efficient XTO start-up circuit (> –1.5kΩ worst case real start-up impedance)
●Changing of modulation type ASK/FSK and data rate without component changes
●Minimal external circuitry requirements for complete system solution
●Adjustable output power: 0 to 10dBm adjusted and stabilized with external resistor
●ESD protection at all pins (1.5kV HBM, 200V MM, 1kV FCDM)
●Supply voltage range: 2.4V to 3.6V or 4.4V to 6.6V
●Temperature range: –40°C to +85°C
●Small 7 ×7mm QFN48 package
Applications
●Consumer industrial segment
●Access control systems
●Remote control systems
●Alarm and telemetry systems
●Energy metering
●Home automation
Benefits
●Low system cost due to very high system integration level
●Only one crystal needed in system
●Less demanding specification for the microcontroller due to handling of power-down mode, delivering of clock, reset, low
battery indication and complete handling of receive/transmit protocol and polling
●Single-ended design with high isolation of PLL/VCO from PA and the power supply allows a loop antenna in the remote control
unit to surround the whole application
3Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
1. General Description
The ATA5428 is a highly integrated UHF ASK/FSK multi-channel half-duplex transceiver with low power consumption supplied
in a small 7 x 7mm QFN48 package. The receive part is built as a fully integrated low-IF receiver, whereas direct PLL
modulation with the fractional-N synthesizer is used for FSK transmission and switching of the power amplifier for ASK
transmission.
The device supports data rates of 1Kbit/s to 20Kbit/s (FSK) and 1Kbit/s to 10Kbit/s (ASK) in Manchester, Bi-phase and other
codes in transparent mode. The ATA5428 can be used in the 431.5MHz to 436.5MHz and in the 862MHz to 872MHz bands.
The very high system integration level results in a small number of external components needed.
Due to its blocking and selectivity performance, together with the additional 15dB to 20dB loss and the narrow bandwidth of a
typical loop antenna in a remote control unit, a bulky blocking SAW is not needed in the remote control unit. Additionally, the
building blocks needed for a typical remote control and access control system on both sides (the base and the mobile stations)
are fully integrated.
Its digital control logic with self-polling and protocol generation enables a fast challenge-response system without using a high-
performance microcontroller. Therefore, the ATA5428 contains a FIFO buffer RAM and can compose and receive the physical
messages themselves. This provides more time for the microcontroller to carry out other functions such as calculating crypto
algorithms, composing the logical messages, and controlling other devices. Therefore, a standard 4-/8-bit microcontroller
without special periphery and clocked with the CLK output of about 4.5MHz is sufficient to control the communication link. This
is especially valid for passive entry and access control systems, where within less than 100ms several challenge-response
communications with arbitration of the communication partner have to be handled.
It is hence possible to design bi-directional remote control and access control systems with a fast challenge-response crypto
function, with the same PCB board size and with the same current consumption as uni-directional remote control systems.
Figure 1-1. System Block Diagram
XTO
ATA5428
Antenna
4 to 8
Power
Supply
ATmega
44/88/168
Matching/
RF Switch
Digital Control
Logic
RF Transceiver
Microcontroller
interface
4Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
Figure 1-2. Pinning QFN48
Table 1-1. Pin Description
Pin Symbol Function
1NC Not connected
2NC Not connected
3NC Not connected
4RF_IN RF input
5NC Not connected
6433_N868 Selects RF input/output frequency range
7NC Not connected
8R_PWR Resistor to adjust output power
9PWR_H Pin to select output power
10 RF_OUT RF output
11 NC Not connected
12 NC Not connected
13 NC Not connected
14 NC Not connected
15 NC Not connected
16 AVCC Blocking of the analog voltage supply
17 VS2 Power supply input for voltage range 4.4V to 6.6V
18 VS1 Power supply input for voltage range 2.4V to 3.6V
RSSI
CS
SCK
SDI_TMDI
SDO_TMDO
ATA5428 CLK
VSINT
XTAL2
25
NC
N_RESET
IRQ
DEM_OUT
NC
NC
RF_IN
NC
433_N868
NC
RF_OUT
NC
PWR_H
R_PWR
NC
NC
NC
AVCC
VS2
VS1
VAUX
TEST1
DVCC
VSOUT
TEST2
TXAL1
NC
RX_ACTIVE
T1
T2
T3
T4
T5
PWR_ON
RX_TX1
RX_TX2
CDEM
1
2
3
4
9
10
11
5
6
8
7
36
35
34
33
28
27
26
32
31
29
30
NC 12
47 46 45 44 38 373941 404243
14
NC NC
48
13 15 16 17 23 242220 211918
5Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
19 VAUX Auxiliary supply voltage input
20 TEST1 Test input, at GND during operation
21 DVCC Blocking of the digital voltage supply
22 VSOUT Output voltage power supply for external devices
23 TEST2 Test input, at GND during operation
24 XTAL1 Reference crystal
25 XTAL2 Reference crystal
26 NC Not connected
27 VSINT Microcontroller interface supply voltage
28 N_RESET Output pin to reset a connected microcontroller
29 IRQ Interrupt request
30 CLK Clock output to connect a microcontroller
31 SDO_TMDO Serial data out/transparent mode data out
32 SDI_TMDI Serial data in/transparent mode data in
33 SCK Serial clock
34 DEM_OUT Demodulator open drain output signal
35 CS Chip select for serial interface
36 RSSI Output of the RSSI amplifier
37 CDEM Capacitor to adjust the lower cut-off frequency data filter
38 RX_TX2 GND pin to decouple LNA in TX mode
39 RX_TX1 Switch pin to decouple LNA in TX mode
40 PWR_ON Input to switch on the system (active high)
41 T5 Key input 5 (can also be used to switch on the system (active low))
42 T4 Key input 4 (can also be used to switch on the system (active low))
43 T3 Key input 3 (can also be used to switch on the system (active low))
44 T2 Key input 2 (can also be used to switch on the system (active low))
45 T1 Key input 1 (can also be used to switch on the system (active low))
46 RX_ACTIVE Indicates RX operation mode
47 NC Not connected
48 NC Not connected
GND Ground/backplane
Table 1-1. Pin Description (Continued)
Pin Symbol Function
6Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
Figure 1-3. Block Diagram
Signal
Processing
(Mixer
IF-filter
IF-amplifier
FSK/ASK
Demodulator,
Data filter
Data Slicer)
TX/RX - Data buffer
Control register
Status register
Polling circuit
Bit-check logic
Digital Control Logic Power
Supply
Switches
Regulators
Wake-up
Reset
RF transceiver
Fractional-N
frequency
synthesizer
VS2
VAUX
VSOUT
VS1
433_N868
PWR_H
CS
SDO_TMDO
IRQ
N_RESET
CLK
DEM_OUT
XTAL2
XTAL1
RSSI
CDEM
RF_IN
RX_TX2
RX_TX1
RF_OUT
R_PWR
DVCCRX_ACTIVEAVCC
GNDVSINT
LNA
SPI
XTO
Reset
PA
RX/TX
switch
Frontend Enable
PA_Enable (ASK)
Demod_Out
FREF
FREQ
RX/TX
13
TX_DATA (FSK)
Microcontroller
interface
SCK
SDI_TMDI
T4
T5
TEST2
TEST1
T1
T3
T2
PWR_ON
7Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
2. Application Circuits
2.1 Typical Remote Control Unit Application with 1 Li Battery (3V)
Figure 2-1 shows a typical 433.92MHz Remote Control Unit application with one battery. The external components are
11 capacitors, 1 resistor, 2 inductors and a crystal. C1 to C4 are 68nF voltage supply blocking capacitors. C5 is a 10nF supply
blocking capacitor. C6 is a 15nF fixed capacitor used for the internal quasi-peak detector and for the high-pass frequency of the
data filter. C7 to C11 are RF matching capacitors in the range of 1pF to 33pF. L1 is a matching inductor of about 5.6nH to 56nH.
L2 is a feed inductor of about 120nH. A load capacitor of 9pF for the crystal is integrated. R1 is typically 22kΩ and sets the output
power to about 5.5dBm. The loop antenna’s quality factor is somewhat reduced by this application due to the quality factor of L2
and the RX/TX switch. On the other hand, this lower quality factor is necessary to have a robust design with a bandwidth that is
broad enough for production tolerances. Due to the single-ended and ground-referenced design, the loop antenna can be a
free-form wire around the application as it is usually employed in remote control uni-directional systems. The ATA5428 provides
sufficient isolation and robust pulling behavior of internal circuits from the supply voltage as well as an integrated VCO inductor
to allow this. Since the efficiency of a loop antenna is proportional to the square of the surrounded area it is beneficial to have a
large loop around the application board with a lower quality factor in order to relax the tolerance specification of the RF
components and to get a high antenna efficiency in spite of their lower quality factor.
Figure 2-1. Typical Remote Control Unit Application, 433.92MHz, 1 Li Battery (3V)
CS
NC
RSSI
CDEM
SCK
DEM_OUT
SDI_TMDI
SDO_TMDO
ATA5428
CLK
VCC VSS
Sensor
VSINT
XTAL2
+ Lithium cell
Loop antenna
AVCC
20mm x 0.4mm
ATmega
48/88/168
13.25311MHz
N_RESET
IRQ
NC
NC
RF_IN
C2
C7
C11 C6
C3
C1
C4
433_N868
NC
NC
NC
RF_OUT
PWR_H
R_PWR
NC
AVCC
VS2
NC
NC
NC
VS1
VAUX
TEST1
DVCC
VSOUT
TEST2
TXAL1
T1
NC
NC
RX_ACTIVE
T2
T3
T4
T5
PWR_ON
RX_TX1
RX_TX2
NC
C9
C10
R1
L2
L1
C8
C5
8Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
2.2 Typical Base-station Application (5V)
Figure 2.2 shows a typical 433.92MHz VCC = 4.75V to 5.25V Base-station Application (5V). The external components are
12 capacitors, 1 resistor, 4 inductors, a SAW filter, and a crystal. C1 and C3 to C4 are 68nF voltage supply blocking capacitors.
C2 and C12 are 2.2µF supply blocking capacitors for the internal voltage regulators. C5 is a 10nF supply blocking capacitor. C6 is
a 15 nF fixed capacitor used for the internal quasi-peak detector and for the high-pass frequency of the data filter. C7 to C11 are
RF matching capacitors in the range of 1pF to 33pF. L2 to L4 are matching inductors of about 5.6nH to 56nH. A load capacitor
for the crystal of 9pF is integrated. R1 is typically 22kΩ and sets the output power at RF_OUT to about 10dBm. Since a quarter
wave or PCB antenna, which has high efficiency and wide band operation, is typically used here, it is recommended to use a
SAW filter to achieve high sensitivity in case of powerful out-of-band blockers. L1, C9 and C10 together form a low-pass filter,
which is needed to filter out the harmonics in the transmitted signal to meet regulations. An internally regulated voltage at pin
VSOUT can be used in case the microcontroller only supports 3.3V operation, a blocking capacitor with a value of C12 = 2.2µF
has to be connected to VSOUT in any case.
Figure 2-2. Typical Base-station Application (5V), 433.92MHz
CS
NC
RSSI
CDEM
SCK
DEM_OUT
SDI_TMDI
SDO_TMDO
CLK
VSINT
XTAL2
AVCC
50Ω
connector
SAW-Filter
20mm x 0.4mm
13.25311MHz
VCC = 4.75V to 5.25V
N_RESET
IRQ
NC
NC
RF_IN
C7
C11 C6
C3
C2
C1C4
C12
433_N868
NC
NC
NC
RF_OUT
PWR_H
R_PWR
NC
AVCC
VS2
NC
NC
NC
VS1
VAUX
TEST1
DVCC
VSOUT
TEST2
TXAL1
T1
NC
NC
RX_ACTIVE
T2
T3
T4
T5
PWR_ON
RX_TX1
RX_TX2
NC
C10 C9
RFOUT
R1
L2
L1
L4
C8
C5
L3
VCC VSS
Sensor
ATmega
48/88/168
ATA5428
9Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
2.3 Typical Remote Control Unit Application, 2 Li Batteries (6V)
Figure 2-3 shows a typical 433.92Hz 2 Li battery Remote Control Unit application. The external components are 11 capacitors,
1 resistor, 2 inductors and a crystal. C1 and C4 are 68nF voltage supply blocking capacitors. C2 and C3 are 2.2µF supply
blocking capacitors for the internal voltage regulators. C5 is a 10nF supply blocking capacitor. C6 is a 15nF fixed capacitor used
for the internal quasi-peak detector and for the high-pass frequency of the data filter. C7 to C11 are RF matching capacitors in
the range of 1pF to 33pF. L1 is a matching inductor of about 5.6nH to 56nH. L2 is a feed inductor of about 120nH. A load
capacitor for the crystal of 9pF is integrated. R1 is typically 22kΩ and sets the output power to about 5.5dBm.
Figure 2-3. Typical Remote Control Unit Application, 433.92MHz, 2 Li Batteries (6V)
CS
NC
RSSI
CDEM
SCK
DEM_OUT
SDI_TMDI
SDO_TMDO
ATA5428
CLK
VCC VSS
Sensor
VSINT
XTAL2
+ Lithium cell
Loop antenna
AVCC
20mm x 0.4mm
ATmega
48/88/168
13.25311MHz
N_RESET
IRQ
NC
NC
RF_IN
C7
C11 C6
C3
C1
C4
433_N868
NC
NC
NC
RF_OUT
PWR_H
R_PWR
NC
AVCC
VS2
NC
NC
NC
VS1
VAUX
TEST1
DVCC
VSOUT
TEST2
TXAL1
T1
NC
NC
RX_ACTIVE
T2
T3
T4
T5
PWR_ON
RX_TX1
RX_TX2
NC
C2
C9
C10
R1
L2
L1
C8
C5
+ Lithium cell
10Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
3. RF Transceiver
As seen in Figure 1-3 on page 6, the RF transceiver consists of an LNA (Low-noise Amplifier), PA (Power Amplifier), RX/TX
switch, fractional-N frequency synthesizer and the signal processing part with mixer, IF filter, IF amplifier with analog RSSI,
FSK/ASK demodulator, data filter, and data slicer.
In receive mode the LNA pre-amplifies the received signal which is converted down to 226kHz (ATA5428), filtered and amplified
before it is fed into an FSK/ASK demodulator, data filter, and data slicer. The RSSI (Received Signal Strength Indicator) signal
and the raw digital output signal of the demodulator are available at the pins RSSI and DEM_OUT. The demodulated data
signal Demod_Out is fed to the digital control logic where it is evaluated and buffered as described in section “Digital Control
Logic” on page 31.
In transmit mode, the fractional-N frequency synthesizer generates the TX frequency which is fed to the PA. In ASK mode the
PA is modulated by the signal PA_Enable. In FSK mode the PA is enabled and the signal TX_DATA (FSK) modulates the
fractional-N frequency synthesizer. The frequency deviation is digitally controlled and internally fixed to about ±16kHz (see
Table 4-1 on page 23 for exact values). The transmit data can also be buffered as described in section “Digital Control Logic” on
page 31. A lock detector within the synthesizer ensures that the transmission will start only if the synthesizer is locked.
The RX/TX switch can be used to combine the LNA input and the PA output to a single antenna with a minimum of losses.
Transparent modes without buffering of RX and TX data are also available to allow protocols and coding schemes other than
the internally supported Manchester encoding.
3.1 Low-IF Receiver
The receive path consists of a fully integrated low-IF receiver. It fulfills the sensitivity, blocking, selectivity, supply voltage and
supply current specification needed to manufacture, for example, an automotive remote control unit without the use of SAW
blocking filter (see Figure 2-1 on page 7). In a Base-station Application (5V) the receiver can be used with an additional blocking
SAW front-end filter as shown in Figure 2.2 on page 8.
At 433.92MHz the receiver has a typical system noise figure of 7.0dB, a system I1dBCP of -30dBm and a system IIP3 of –
20dBm. There is no AGC or switching of the LNA needed; thus, a better blocking performance is achieved. This receiver uses
an IF (Intermediate Frequency) of 226kHz, the typical image rejection is 30dB and the typical 3dB IF filter bandwidth is 185kHz
(fIF = 226kHz ±92.5kHz, flo_IF = 133.5kHz and fhi_IF = 318.5kHz). The demodulator needs a signal to Gaussian noise ratio of 8dB
for 20Kbit/s Manchester with ±16kHz frequency deviation in FSK mode; thus, the resulting sensitivity at 433.92MHz is typically
–106dBm at 20Kbit/s Manchester.
Due to the low phase noise and spurious emissions of the synthesizer in receive mode(1) together with the eighth order
integrated IF filter, the receiver has a better selectivity and blocking performance than more complex double superhet receivers
but without external components and without numerous spurious receiving frequencies.
A low-IF architecture is also less sensitive to second-order intermodulation (IIP2) than direct conversion receivers, where every
pulse or AM-modulated signal (especially the signals from TDMA systems like GSM) demodulates to the receiving signal band
at second-order non-linearities.
Note: 1. –120dBC/Hz at ±1MHz and –75dBC at ±FREF at 433.92MHz
3.2 Input Matching at RF_IN
The measured input impedances as well as the values of a parallel equivalent circuit of these impedances can be seen in the
Table 3-1. The highest sensitivity is achieved with power matching of these impedances to the source impedance of 50Ω.
Table 3-1. Measured Input Impedances of the RF_IN Pin
fRF/MHz Z(RF_IN) Rp//Cp
433.92 (32-j169)Ω925Ω//2.1pF
868.3 (21-j78)Ω311Ω//2.2pF
11Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
The matching of the LNA Input to 50Ω was done with the circuit shown in Figure 3-1 and with the values given in Table 3-2 on
page 11. The reflection coefficients were always ≤10dB. Note that value changes of C1 and L1 may be necessary to compensate
for individual board layouts. The measured typical FSK and ASK Manchester code sensitivities with a Bit Error Rate (BER) of
10-3 are shown in Table 3-3 on page 11 and Table 3-4 on page 11. These measurements were done with inductors having a
quality factor according to Table 3-2 on page 11, resulting in estimated matching losses of 0.7dB at 433.92MHz, 0.7dB at
868.3MHz. These losses can be estimated when calculating the parallel equivalent resistance of the inductor with
Rloss =2×π×f×L×QL and the matching loss with 10 log(1 + Rp/Rloss).
With an ideal inductor, for example, the sensitivity at 433.92MHz/FSK/20Kbit/s/±16kHz/Manchester can be improved from –
106dBm to –106.7dBm. The sensitivity depends on the control logic which examines the incoming data stream. The
examination limits must be programmed in control registers 5 and 6. The measurements in Table 3-3 on page 11 and Table 3-4
on page 11 are based on the values of registers 5 and 6 according to Table 9-3 on page 54.
Figure 3-1. Input Matching to 50Ω
Table 3-2. Input Matching to 50Ω
fRF/MHz C1/pF L1/nH QL1
433.92 1.8 27 70
868.3 1.2 6.8 50
Table 3-3. Measured Sensitivity FSK, ±16kHz, Manchester, dBm, BER = 10–3
RF Frequency
BR_Range_0
1.0Kbit/s
BR_Range_0
2.4Kbit/s
BR_Range_1
5.0Kbit/s
BR_Range_2
10Kbit/s
BR_Range_3
20Kbit/s
433.92MHz –109.0dBm –109.5dBm –108.0dBm –107.0dBm –106.0dBm
868.3MHz –106.0dBm –106.5dBm –105.5dBm –104.0dBm –103.5dBm
Table 3-4. Measured Sensitivity 100% ASK, Manchester, dBm, BER = 10–3
RF Frequency
BR_Range_0
1.0Kbit/s
BR_Range_0
2.4Kbit/s
BR_Range_1
5.0Kbit/s
BR_Range_2
10Kbit/s
433.92MHz –116.0dBm –116.5dBm –114.0dBm –112.5dBm
868.3MHz –112.5dBm –113.0dBm –111.5dBm –109.5dBm
L1
C14RF_IN
ATA5428
12Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
3.3 Sensitivity versus Supply Voltage, Temperature and Frequency Offset
To calculate the behavior of a transmission system it is important to know the reduction of the sensitivity due to several
influences. The most important are frequency offset due to crystal oscillator (XTO) and crystal frequency (XTAL) errors,
temperature and supply voltage dependency of the noise figure and IF filter bandwidth of the receiver. Figure 3-2 shows the
typical sensitivity at 433.92MHz/FSK/20Kbit/s/±16kHz/Manchester versus the frequency offset between transmitter and receiver
with Tamb = –40°C, +25°C and +105°C and supply voltage VS1 = VS2 = 2.4V, 3.0V and 3.6V.
Figure 3-2. Measured Sensitivity 433.92MHz/FSK/20Kbit/s/±16kHz/Manchester versus Frequency Offset, Temperature
and Supply Voltage
As can be seen in Figure 3-2 on page 12 the supply voltage has almost no influence. The temperature has an influence of about
+1.5/–0.7dB, and a frequency offset of ±65kHz also influences by about ±1dB. All these influences, combined with the
sensitivity of a typical IC, are then within a range of –103.7dBm and –107.3dBm over temperature, supply voltage and
frequency offset which is –105.5dBm ±1.8dB. The integrated IF filter has an additional production tolerance of only ±7kHz,
hence, a frequency offset between the receiver and the transmitter of ±58kHz can be accepted for XTAL and XTO tolerances.
This small sensitivity spread over supply voltage, frequency offset and temperature is very unusual in such a receiver. It is
achieved by an internal, very fast and automatic frequency correction in the FSK demodulator after the IF filter, which leads to a
higher system margin. This frequency correction tracks the input frequency very quickly; if, however, the input frequency makes
a larger step (for example, if the system changes between different communication partners), the receiver has to be restarted.
This can be done by switching back to IDLE mode and then again to RX mode. For that purpose, an automatic mode is also
available. This automatic mode switches to IDLE mode and back into RX mode every time a bit error occurs (see Section 7. on
page 31).
3.4 Frequency Accuracy of the Crystals
The XTO is an amplitude regulated Pierce oscillator with integrated load capacitors. The initial tolerances (due to the frequency
tolerance of the XTAL, the integrated capacitors on XTAL1, XTAL2 and the XTO’s initial transconductance gm) can be
compensated to a value within ±0.5ppm by measuring the CLK output frequency and programming the control registers 2 and 3
(see Table 7-7 on page 33 and Table 7-10 on page 34). The XTO then has a remaining influence of less than ±2ppm over
temperature and supply voltage due to the band gap controlled gm of the XTO.
The needed frequency stability of the used crystals over temperature and aging is hence
±58kHz/433.92MHz – 2 ×±2.5ppm = ±128.6ppm for 433.92Mz,
±58kHz/868.3MHz – 2 ×±2.5ppm = ±61.8ppm for 868.3MHz.
Thus, the used crystals in receiver and transmitter each need to be better than ±64.3ppm for 433.92MHz, ±30.9ppm for
868.3MHz. In access control systems it may be advantageous to have a more tight tolerance at the Base-station in order to
relax the requirement for the remote control unit.
-109
-108
-107
-106
-105
-104
-103
-102
-101
-100
-99
-98
-97
-96
-95
-110
-60 40 60 10080-40-80-100 0
Frequenc
y
Offset (kHz)
Sensitivity (dBm)
20-20
VS = 3.0V Tamb = -40°C
VS = 3.6V Tamb = -40°C
VS = 3.0V Tamb = +25°C
VS = 3.6V Tamb = +25°C
VS = 2.4V Tamb = +105°C
VS = 3.0V Tamb = +105°C
VS = 3.6V Tamb = +105°C
VS = 2.4V Tamb = +25°C
VS = 2.4V Tamb = -40°C
13Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
3.5 RX Supply Current versus Temperature and Supply Voltage
Table 3-5 shows the typical supply current at 433.92MHz of the transceiver in RX mode versus supply voltage and temperature
with VS = VS1 = VS2. As can be seen, the supply current at 2.4V and –40°C is less than the typical supply current; this is useful
because this is also the operation point where a lithium cell has the worst performance. The typical supply current at 868.3MHz
in RX mode is about the same as for 433.92MHz.
3.6 Blocking, Selectivity
As can be seen in Figure 3-3 and Figure 3-4 on page 13, the receiver can receive signals 3dB higher than the sensitivity level in
the presence of very large blockers of –47dBm/–34dBm with small frequency offsets of ±1/±10MHz.
Figure 3-3 shows narrow band blocking and Figure 3-4 wide band blocking characteristics. The measurements were done with
a signal of 433.92MHz/FSK/20Kbit/s/±16kHz/Manchester, and with a level of –106dBm + 3dB = –103dBm which is 3dB above
the sensitivity level. The figures show how much larger than –103dBm a continuous wave signal can be before the BER is
higher than 10–3. The measurements were done at the 50Ω input according to Figure 3-1 on page 11. At 1MHz, for example, the
blocker can be 56dB higher than –103dBm which is -103dBm + 56dB = –47dBm. These values, together with the good
intermodulation performance, avoid the need for a SAW filter in the remote control unit application.
Figure 3-3. Narrow Band 3dB Blocking Characteristic at 433.92MHz
Figure 3-4. Wide Band 3dB Blocking Characteristic at 433.92MHz
Table 3-5. Measured 433.92 MHz Receive Supply Current in FSK Mode
VS = VS1 = VS2 2.4V 3.0V 3.6V
Tamb = –40°C 8.4mA 8.8mA 9.2mA
Tamb = 25°C 9.9mA 10.3mA 10.8mA
Tamb = 85°C 10.9mA 11.3mA 11.8mA
70
50
60
40
20
30
-1 0 1 2-5 -4 -3 -2
Distance of Interfering to Receiving Signal (MHz)
Blocking Level (dBC)
10
-10
0
34
5
80
60
70
50
30
40
Blocking Level (dBC)
20
-10
0
10
-10 0 10 20-50 -40 -30 -20
Distance of Interfering to Receiving Signal (MHz)
30 40 50
14Atmel ATA5428 [DATASHEET]
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Figure 3-5 on page 14 shows the blocking measurement close to the received frequency to illustrate the selectivity and image
rejection. This measurement was done 6dB above the sensitivity level with a useful signal of
433.92MHz/FSK/20Kbit/s/±16kHz/Manchester with a level of –106dBm + 6dB = –100dBm. The figure shows to which extent a
continuous wave signal can surpass –100dBm until the BER is higher than 10-3. For example, at 1MHz the blocker can then be
59dB higher than –100dBm which is –100dBm + 59dB = –41dBm.
Table 3-6 on page 14 shows the blocking performance measured relative to –100dBm for some other frequencies. Note that
sometimes the blocking is measured relative to the sensitivity level (dBS) instead of the carrier (dBC).
The ATA5428 can also receive FSK and ASK modulated signals if they are much higher than the I1dBCP. It can typically
receive useful signals at 10dBm. This is often referred to as the nonlinear dynamic range which is the maximum to minimum
receiving signal and is 116dB for 20Kbit/s Manchester. This value is useful if two transceivers have to communicate and are
very close to each other.
Figure 3-5. Close In 6dB Blocking Characteristic and Image Response at 433.92MHz
This high blocking performance even makes it possible for some applications using quarter wave whip antennas to use a simple
LC band-pass filter instead of a SAW filter in the receiver.
When designing such an LC filter take into account that the 3dB blocking at 433.92MHz/2 = 216.96MHz is 43dBC and at
433.92MHz/3 = 144.64MHz is 48dBC and at 2 ×(433.92MHz + 226kHz) + –226kHz = 868.066MHz/868.518MHz is 56dBC.
And especially that at 3 ×(433.92MHz + 226kHz) + 226kHz = 1302.664MHz the receiver has its second LO harmonic receiving
frequency with only 12dBC blocking.
3.7 In-band Disturbers, Data Filter, Quasi-peak Detector, Data Slicer
If a disturbing signal falls into the received band or a blocker is not continuous wave, the performance of a receiver strongly
depends on the circuits after the IF filter. The demodulator, data filter and data slicer are important, in that case.
The data filter of the ATA5428 implies a quasi-peak detector. This results in a good suppression of the above mentioned
disturbers and exhibits a good carrier to Gaussian noise performance. The required useful signal to disturbing signal ratio to be
received with a BER of 10–3 is less than 12dB in ASK mode and less than 3dB (BR_Range_0 to BR_Range_2)/6dB
(BR_Range_3) in FSK mode.
Table 3-6. Blocking 6dB Above Sensitivity Level with BER < 10–3
Frequency Offset Blocker Level Blocking
+0.75MHz –45dBm 55dBC/61dBS
–0.75MHz –45dBm 55dBC/61dBS
+1.5MHz –38dBm 62dBC/68dBS
–1.5MHz –38dBm 62dBC/68dBS
+10MHz –30dBm 70dBC/76dBS
–10MHz –30dBm 70dBC/76dBS
70
50
60
40
20
30
Blocking Level (dBC)
10
-10
0
-0.2 0 0.2 0.4-1.0 -0.8 -0.6 -0.4
Distance of Interfering to Receiving Signal (MHz)
0.6 0.8 1.0
Distance of Interfering to Receiving Signal (MHz)
Blocking Level (dBC)
15Atmel ATA5428 [DATASHEET]
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Due to the many different waveforms possible these numbers are measured for signal as well as for disturbers with peak
amplitude values. Note that these values are worst case values and are valid for any type of modulation and modulating
frequency of the disturbing signal as well as the receiving signal. For many combinations, lower carrier to disturbing signal ratios
are needed.
3.8 DEM_OUT Output
The internal raw output signal of the demodulator Demod_Out is available at pin DEM_OUT. DEM_OUT is an open drain output
and must be connected to a pull-up resistor if it is used (typically 100kΩ) otherwise no signal is present at that pin.
3.9 RSSI Output
The output voltage of the pin RSSI is an analog voltage, proportional to the input power level. Using the RSSI output signal, the
signal strength of different transmitters can be distinguished. The usable dynamic range of the RSSI amplifier is 70dB, the input
power range P(RFIN) is –115dBm to –45dBm and the gain is 8mV/dB. Figure 3-6 shows the RSSI characteristic of a typical
device at 433.92MHz with VS1 = VS2 = 2.4V to 3.6V and Tamb = –40°C to +85°C with a matched input according to Table 3-2 on
page 11 and Figure 3-1 on page 11. At 868.3MHz about 2.7dB more signal level is needed for the same RSSI results.
Figure 3-6. Typical RSSI Characteristic versus Temperature and Supply Voltage
3.10 Frequency Synthesizer
The synthesizer is a fully integrated fractional-N design with internal loop filters for receive and transmit mode. The XTO
frequency fXTO is the reference frequency FREF for the synthesizer. The bits FR0 to FR12 in control registers 2 and 3 (see Ta ble
7-7 on page 33 and Table 7-10 on page 34) are used to adjust the deviation of fXTO. In transmit mode, at 433.92MHz, the carrier
has a phase noise of –111dBC/Hz at 1MHz and spurious emissions at FREF of –66dBC with a high PLL loop bandwidth
allowing the direct modulation of the carrier with 20Kbit/s Manchester data. Due to the closed loop modulation any spurious
emissions caused by this modulation are effectively filtered out as can be seen in Figure 3-9 on page 17. In RX mode the
synthesizer has a phase noise of –120dBC/Hz at 1MHz and spurious emissions of –75dBC.
The initial tolerances of the crystal oscillator due to crystal tolerances, internal capacitor tolerances and the parasitics of the
board have to be compensated at manufacturing setup with control registers 2 and 3 as can be seen in Table 4-1 on page 23.
The other control words for the synthesizer needed for ASK, FSK and receive/transmit switching are calculated internally. The
RF (Radio Frequency) resolution is equal to the XTO frequency divided by 16384 which is 808.9Hz at 433.92MHz, 818.6Hz at
868.3MHz.
For the multi-channel system the frequency control word FREQ in control registers 2 and 3 can be programmed in the range of
1000 to 6900, this is equivalent to a programmable tuning range of ±2.5MHz hence every frequency within the 433MHz,
868MHz ISM bands can be programmed as receive and as transmit frequency, and the position of channels within these ISM
bands can be chosen arbitrarily (see Table 4-1 on page 23).
Care must be taken as to the harmonics of the CLK output signal as well as to the harmonics produced by a microprocessor
clocked with it, since these harmonics can disturb the reception of signals. In a single-channel system, using FREQ = 3803 to
4053 ensures that harmonics of this signal do not disturb the receive mode.
400
500
600
700
800
900
1000
1100
-80 -70 -60 -50-120 -110 -100 -90
PRF_IN (dBm)
VRSSI (mV)
-40
max.
min. typ.
16Atmel ATA5428 [DATASHEET]
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3.11 FSK/ASK Transmission
Due to the fast modulation capability of the synthesizer and the high resolution, the carrier can be internally FSK modulated,
which simplifies the application of the transceiver. The deviation of the transmitted signal is ±20 digital frequency steps of the
synthesizer which is equal to ±16.17kHz for 433.92MHz, ±16.37kHz for 868.3MHz.
Due to closed loop modulation with PLL filtering the modulated spectrum is very clean, meeting ETSI and CEPT regulations
when using a simple LC filter for the power amplifier harmonics as it is shown in Figure 2.2 on page 8. In ASK mode the
frequency is internally connected to the center of the FSK transmission and the power amplifier is switched on and off to
perform the modulation. Figure 3-7 to Figure 3-9 on page 17 show the spectrum of the FSK modulation with pseudo-random
data with 20Kbit/s/±16.17kHz/Manchester and 5dBm output power.
Figure 3-7. FSK-modulated TX Spectrum (433.92MHz/20Kbit/s/±16.17kHz/Manchester Code)
Atten 20dB
VAvg
50
S3 FC
W1 S2
Ref 10dB
Span 30MHz
Sweep 7.5ms (401 pts)
Center 433.92MHz
VBW 100kHzRes BW 100kHz
Samp
Log
dB/
10
17Atmel ATA5428 [DATASHEET]
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Figure 3-8. Unmodulated TX Spectrum 433.92MHz – 16.17kHz (fFSK_L)
Figure 3-9. FSK-modulated TX Spectrum (433.92MHz/20Kbit/s/±16.17kHz/Manchester Code)
Atten 20dB
Span 1MHz
Sweep 27.5ms (401 pts)
Center 433.92MHz
VBW 10kHzRes BW 10kHz
VAvg
50
S3 FC
W1 S2
Ref 10dB
Samp
Log
dB/
10
Span 1MHz
Sweep 27.5ms (401 pts)
Center 433.92MHz
VBW 10kHzRes BW 10kHz
Atten 20dB
VAvg
50
S3 FC
W1 S2
Ref 10dB
Samp
Log
dB/
10
18Atmel ATA5428 [DATASHEET]
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3.12 Output Power Setting and PA Matching at RF_OUT
The Power Amplifier (PA) is a single-ended open collector stage which delivers a current pulse which is nearly independent of
supply voltage, temperature and tolerances due to band gap stabilization. Resistor R1, see Figure 3-10, sets a reference current
which controls the current in the PA. A higher resistor value results in a lower reference current, a lower output power and a
lower current consumption of the PA. The usable range of R1 is 15kΩ to 56kΩ. Pin PWR_H switches the output power range
between about 0dBm to 5dBm (PWR_H = GND) and 5dBm to 10dBm (PWR_H = AVCC) by multiplying this reference current
by a factor 1 (PWR_H = GND) and 2.5 (PWR_H = AVCC), which corresponds to about 5dB more output power.
If the PA is switched off in TX mode, the current consumption without output stage with VS1 = VS2 = 3V, Tamb = 25°C is
typically 6.5mA for 868.3MHz and 6.95mA for 433.92MHz.
The maximum output power is achieved with optimum load resistances RLopt according to Table 3-7 on page 19 with
compensation of the 1.0pF output capacitance of the RF_OUT pin by absorbing it into the matching network consisting of L1,
C1, C3 as shown in Figure 3-10 on page 18. There must also be a low resistive DC path to AVCC to deliver the DC current of the
power amplifier's last stage. The matching of the PA output was done with the circuit shown in Figure 3-10 on page 18 with the
values in Table 3-7 on page 19. Note that value changes of these elements may be necessary to compensate for individual
board layouts.
Example:
According to Table 3-7 on page 19, with a frequency of 433.92 MHz and output power of 11dBm the overall current consumption
is typically 17.8mA; hence, the PA needs 17.8mA - 6.95mA = 10.85mA in this mode, which corresponds to an overall power
amplifier efficiency of the PA of (10(11dBm/10) × 1 mW)/(3V ×10.85mA) × 100% = 38.6% in this case.
Using a higher resistor in this example of R1=1.091×22kΩ=24kΩ results in 9.1% less current in the PA of 10.85mA/1.091 =
9.95mA and 10 × log(1.091) = 0.38dB less output power if using a new load resistance of 300Ω× 1.091 = 327Ω. The resulting
output power is then 11dBm – 0.38dB = 10.6dBm and the overall current consumption is 6.95mA + 9.95mA = 16.9mA.
The values of Table 3-7 on page 19 were measured with standard multi-layer chip inductors with quality factors Q according to
Table 3-7 on page 19. Looking to the 433.92MHz/11dBm case with the quality factor of QL1 = 43 the loss in this inductor is
estimated with the parallel equivalent resistance of the inductor Rloss =2×π×f×L×QL1 and the matching loss with
10log(1+R
Lopt/Rloss) which is equal to 0.32dB losses in this inductor. Taking this into account, the PA efficiency is then 42%
instead of 38.6%.
Be aware that the high power mode (PWR_H = AVCC) can only be used with a supply voltage higher than 2.7V, whereas the
low power mode (PWR_H = GND) can be used down to 2.4V as can be seen in the “Electrical Characteristics: General” on
page 59.
The supply blocking capacitor C2 (10nF) has to be placed close to the matching network because of the RF current flowing
through it.
Figure 3-10. Power Setting and Output Matching
RF
OUT
10 RF_OUT
VPWR_H
AVCC
ATA5428
9
PWR_H
8R_PWR
C
2
C
1
L
1
C
3
R
1
19Atmel ATA5428 [DATASHEET]
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3.13 Output Power and TX Supply Current versus Supply Voltage and Temperature
Table 3-8 shows the measurement of the output power for a typical device with VS = VS1 = VS2 in the 433.92MHz and 6.2dBm
case versus temperature and supply voltage measured according to Figure 3-10 on page 18 with components according to
Table 3-7. As opposed to the receiver sensitivity, the supply voltage has here the major impact on output power variations
because of the large signal behavior of a power amplifier. Thus, a two battery system with voltage regulator or a 5V system
shows much less variation than a 2.4V to 3.6V one battery system because the supply voltage is then well within 3.0V and 3.6V.
The reason is that the amplitude at the output RF_OUT with optimum load resistance is AVCC – 0.4V and the power is
proportional to (AVCC – 0.4V)2 if the load impedance is not changed. This means that the theoretical output power reduction if
reducing the supply voltage from 3.0V to 2.4V is 10 log ((3V – 0.4V)2/(2.4V – 0.4V)2) = 2.2dB. Table 3-8 shows that principle
behavior in the measurement. This is not the same case for higher voltages, since here increasing the supply voltage from 3V to
3.6V should theoretical increase the power by 1.8dB; but a gain of only 0.8dB in the measurement shows that the amplitude
does not increase with the supply voltage because the load impedance is optimized for 3V and the output amplitude stays more
constant.
Table 3-9 shows the relative changes of the output power of a typical device compared to 3.0V/25°C. As can be seen, a
temperature change to –40°C as well as to +85°C reduces the power by less than 1dB due to the band gap regulated output
current. Measurements of all the cases in Table 3-7 on page 19 over temperature and supply voltage have shown about the
same relative behavior as shown in Table 3-9.
Table 3-7. Measured Output Power and Current Consumption with VS1 = VS2 = 3V, Tamb = 25°C
Frequency
(MHz)
TX Current
(mA)
Output Power
(dBm)
R1
(kΩ)VPWR_H RLopt (Ω)
L1
(nH) QL1
C1
(pF)
C3
(pF)
433.92 8.6 0.1 56 GND 2300 56 40 0.75 0
433.92 11.2 6.2 22 GND 890 47 38 1.5 0
433.92 17.8 11 22 AVCC 300 33 43 2.7 0
868.3 9.3 -0.3 33 GND 1170 12 58 1.0 3.3
868.3 11.5 5.4 15 GND 471 15 54 1.0 0
868.3 16.3 9.5 22 AVCC 245 10 57 1.5 0
Table 3-8. Measured Output Power and Supply Current at 433.92MHz, PWR_H = GND
VS = 2.4 V 3.0 V 3.6 V
Tamb = –40°C 10.19mA
3.8dBm
10.19mA
5.5dBm
10.78mA
6.2dBm
Tamb = +25°C 10.62mA
4.6dBm
11.19mA
6.2dBm
11.79mA
7.1dBm
Tamb = +85°C 11.4mA
3.9dBm
12.02mA
5.5dBm
12.73mA
6.6dBm
20Atmel ATA5428 [DATASHEET]
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3.14 RX/TX Switch
The RX/TX switch decouples the LNA from the PA in TX mode, and directs the received power to the LNA in RX mode. To do
this, it has a low impedance to GND in TX mode and a high impedance to GND in RX mode. To design a proper RX/TX
decoupling, a linear simulation tool for radio frequency design together with the measured device impedances of Table 3-1 on
page 10, Table 3-7 on page 19, Table 3-10 and Table 3-11 on page 21 should be used, but the exact element values have to be
found on-board. Figure 3-11 shows an approximate equivalent circuit of the switch. The principal switching operation is
described here according to the application of Figure 2-1 on page 7. The application of Figure 2.2 on page 8 works similarly.
Figure 3-11. Equivalent Circuit of the Switch
3.15 Matching Network in TX Mode
In TX mode the 20mm long and 0.4mm wide transmission line which is much shorter than λ/4 is approximately switched in
parallel to the capacitor C9 to GND. The antenna connection between C8 and C9 has an impedance of about 50Ω locking from
the transmission line into the loop antenna with pin RF_OUT, L2, C10, C8 and C9 connected (using a C9 without the added 7.6pF
as discussed later). The transmission line can be approximated with a 16nH inductor in series with a 1.5Ω resistor, the closed
switch can be approximated according to Table 3-10 with the series connection of 1.6nH and 5Ω in this mode. To have a parallel
resonant high impedance circuit with little RF power going into it looking from the loop antenna into the transmission line a
capacitor of about 7.6pF to GND is needed at the beginning of the transmission line (this capacitor is later absorbed into C9
which is then higher, as needed for 50Ω transformation). To keep the 50Ω impedance in RX mode at the end of this transmission
line, C7 also has to be about 7.6pF. This reduces the TX power by about 0.5dB at 433.92MHz compared to the case the where
the LNA path is completely disconnected.
Table 3-9. Measurements of Typical Output Power Relative to 3V/25°C
VS = 2.4V 3.0V 3.6V
Tamb = –40°C –2.4dB –0.7dB 0dB
Tamb = +25°C –1.6dB 0dB +0.9dB
Tamb = +85°C –2.3dB –0.7dB +0.4dB
Table 3-10. Impedance of the RX/TX Switch RX_TX2 Shorted to GND
Frequency Z(RX_TX1) TX Mode Z(RX_TX1) RX Mode
433.92MHz (4.5 + j4.3)Ω(10.3 – j153)Ω
868.3MHz (5 + j9)Ω(8.9 – j73)Ω
1.6nH
2.5pF
RX_TX1
TX
11Ω5Ω
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3.16 Matching Network in RX Mode
In RX mode the RF_OUT pin has a high impedance of about 7kΩ in parallel with 1.0pF at 433.92MHz as can be seen in Table
3-11. This, together with the losses of the inductor L2 with 120nH and QL2 = 25, gives about 3.7kΩ loss impedance at RF_OUT.
Since the optimum load impedance in TX mode for the power amplifier at RF_OUT is 890Ω the loss associated with the inductor
L2 and the RF_OUT pin can be estimated to be 10 ×log(1 + 890/3700) = 0.95dB compared to the optimum matched loop
antenna without L2 and RF_OUT. The switch represents, in this mode at 433.92MHz, approximately an inductor of 1.6nH in
series with the parallel connection of 2.5pF and 2.0kΩ. Since the impedance level at pin RX_TX1 in RX mode is about 50Ω this
only negligibly dampens the received signal (by about 0.1dB). When matching the LNA to the loop antenna, the transmission
line and the 7.6pF part of C9 have to be taken into account when choosing the values of C11 and L1 so that the impedance seen
from the loop antenna into the transmission line with the 7.6pF capacitor connected is 50Ω. Since the loop antenna in RX mode
is loaded by the LNA input impedance, the loaded Q of the loop antenna is lowered by about a factor of 2 in RX mode; hence
the antenna bandwidth is higher than in TX mode.
Note that if matching to 50Ω, like in Figure 2.2 on page 8, a high Q wire-wound inductor with a Q > 70 should be used for L2 to
minimize its contribution to RX losses that will otherwise be dominant. The RX and TX losses will be in the range of 1.0dB there.
4. XTO
The XTO is an amplitude-regulated Pierce oscillator type with integrated load capacitances (2 ×18pF with a tolerance of ±17%)
hence CLmin = 7.4pF and CLmax = 10.6pF. The XTO oscillation frequency fXTO is the reference frequency FREF for the fractional-
N synthesizer. When designing the system in terms of receiving and transmitting frequency offset, the accuracy of the crystal
and XTO have to be considered.
The synthesizer can adjust the local oscillator frequency for the initial frequency error in fXTO. This is done at nominal supply
voltage and temperature with the control registers 2 and 3 (see Table 7-7 on page 33 and Table 7-10 on page 34). The
remaining local oscillator tolerance at nominal supply voltage and temperature is then < ±0.5ppm. The XTO’s gm has very low
influence of less than ±2ppm on the frequency at nominal supply voltage and temperature.
In a single channel system less than ±150ppm should be corrected to avoid that harmonics of the CLK output disturb the
receive mode. If the CLK is not used or if it is carefully laid out on the application PCB (as needed for multi channel systems),
more than ±150ppm can be compensated.
Over temperature and supply voltage, the XTO's additional pulling is only ±2ppm. The XTAL versus temperature and its aging is
then the main source of frequency error in the local oscillator.
The XTO frequency depends on XTAL properties and the load capacitances CL1, 2 at pin XTAL1 and XTAL2. The pulling of fXTO
from the nominal fXTAL is calculated using the following formula:
ppm.
Cm is the crystal's motional, C0 the shunt and CLN the nominal load capacitance of the XTAL found in its data sheet. CL is the
total actual load capacitance of the crystal in the circuit and consists of CL1 and CL2 in series connection.
Table 3-11. Impedance RF_OUT Pin in RX Mode
Frequency Z(RF_OUT)RX RP//CP
433.92MHz 19Ω – j 366Ω7kΩ//1.0pF
868.3MHz 2.8Ω – j 141Ω7kΩ//1.3pF
PCm
2
------- CLN CL
–
C0CLN
+()C0CL
+()×
------------------------------------------------------------
×106
×=
22Atmel ATA5428 [DATASHEET]
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Figure 4-1. XTAL with Load Capacitance
With Cm≤14fF, C0≥1.5pF, CLN = 9pF and CL= 7.4pF to 10.6pF, the pulling amounts to P ≤±100ppm and with Cm≤7fF,
C0≥1.5pF, CLN = 9pF and CL= 7.4pF to 10.6pF, the pulling is P ≤ ±50ppm.
Since typical crystals have less than ±50ppm tolerance at 25°C, the compensation is not critical, and can in both cases be done
with the ±150ppm.
C0 of the XTAL has to be lower than CLmin/2 = 3.7pF for a Pierce oscillator type in order to not enter the steep region of pulling
versus load capacitance where there is a risk of an unstable oscillation.
To ensure proper start-up behavior the small signal gain, and thus the negative resistance, provided by this XTO at start is very
large; for example, oscillation starts up even in worst case with a crystal series resistance of 1.5kΩ at C0≤2.2pF with this XTO.
The negative resistance is approximately given by
with Z1, Z2 as complex impedances at pin XTAL1 and XTAL2, hence
Z1 =–j/(2×π×fXTO ×CL1) + 5Ω and Z2 = –j/(2 × π × fXTO × CL2) + 5Ω.
Z3 consists of crystals C0 in parallel with an internal 110 kΩ resistor hence
Z3=–j/(2×π×fXTO ×C0) /110kΩ, gm is the internal transconductance between XTAL1 and XTAL2 with typically 19mS at
25°C.
With fXTO = 13.5MHz, gm = 19mS, CL= 9pF, and C0= 2.2pF, this results in a negative resistance of about 2kΩ. The worst case
for technological, temperature and supply voltage variations is then for C0≤2.2pF always higher than 1.5kΩ.
Due to the large gain at startup, the XTO is able to meet a very low start-up time. The oscillation start-up time can be estimated
with the time constant τ.
After 10τ to 20τ an amplitude detector detects the oscillation amplitude and sets XTO_OK to High if the amplitude is large
enough. This sets N_RESET to High and activates the CLK output if CLK_ON in control register 3 is High (see Table 7-7 on
page 33). Note that the necessary conditions of the VSOUT and DVCC voltage also have to be fulfilled (see Figure 4-2 on page
23 and Figure 5-1 on page 25).
To save current in IDLE and Sleep modes, the load capacitors are partially switched off in these modes with S1 and S2, as seen
in Figure 4-2 on page 23.
It is recommended to use a crystal with Cm= 3.0fF to 7.0fF, CLN = 9pF, Rm<120Ω and C0= 1.0pF to 2.2pF.
Lower values of Cm can be used, this increases the start-up time slightly. Lower values of C0 or higher values of Cm (up to 15fF)
can also be used, this has only little influence on pulling.
C0
CL2
CL1
Cm
LmRm
CL = CL1 × CL2/ (CL1 + CL2)
XTAL
Crystal equivalent circuit
Re ZXTOcore
{}Re Z1Z3Z2Z3Z1
+Z2
×Z3gm
×××+×
Z1Z2Z3Z1Z2
×gm
×+++
---------------------------------------------------------------------------------------------------
⎩⎭
⎨⎬
⎧⎫
=
τ2
4π2
×fm
2
×Cm
×Re ZXTOcore
()Rm
+()×
--------------------------------------------------------------------------------------------------------=
23Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
Figure 4-2. XTO Block Diagram
To find the right values used in control registers 2 and 3 (see Table 7-7 on page 33 and Table 7-10 on page 34), the relationship
between fXTO and the fRF is shown in Table 4-1 on page 23. To determine the right content, the frequency at pin CLK as
well as the output frequency at RF_OUT in ASK mode can be measured, then the FREQ value can be calculated according to
Table 4-1 on page 23 so that fRF is exactly the desired radio frequency.
8pF 8pF
XTAL1
Divider
/16
CLK_ON
(control
register 3)
VSOUT_OK
(from power supply)
DVCC_OK
(from power supply)
Baud1
In IDLE mode and during Sleep mode (RX_Polling)
the switches S1 and S2 are open.
XLim
Baud0
&
Divider
/3
XTO_OK
(to reset logic)
Divider
/1
/2
/4
/8
/16
10pF10pF
Amplitude
detector
S2S1
fXDCLK
XTAL2 CLK
CL2
CL1
fXTO
fDCLK
Table 4-1. Calculation of fRF
Frequency
(MHz)
Pin 6
433_N868
CREG1
Bit(4)
FS fXTO (MHz) fRF = fTX_ASK = fRX fTX_FSK_L fTX_FSK_H
Frequency
Resolution
433.92 AVCC 013.25311 fRF –16.17kHz fRF +
16.17kHz 808.9Hz
868.3 GND 013.41191 fRF –16.37kHz fRF +
16.37kHz 818.6Hz
fXTO 32.5 FREQ 20.5+
16384
--------------------------------+
⎝⎠
⎛⎞
×
fXTO 64.5 FREQ 20.5+
16384
--------------------------------+
⎝⎠
⎛⎞
×
24Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
The variable FREQ depends on FREQ2 and FREQ3, which are defined by the bits FR0 to FR12 in control register 2 and 3, and
is calculated as follows:
FREQ = FREQ2 + FREQ3
Care must be taken to the harmonics of the CLK output signal fCLK as well as to the harmonics produced by an microprocessor
clocked with it, since these harmonics can disturb the reception of signals if they get to the RF input. In a single channel system,
using FREQ = 3803 to 4053 ensures that the harmonics of this signal do not disturb the receive mode. In a multichannel
system, the CLK signal can either be not used or carefully laid out on the application PCB. The supply voltage of the
microcontroller must also be carefully blocked in a multichannel system.
4.1 Pin CLK
Pin CLK is an output to clock a connected microcontroller. The clock frequency fCLK is calculated as follows:
Because the enabling of pin CLK is asynchronous, the first clock cycle may be incomplete. The signal at CLK output has a
nominal 50% duty cycle.
Figure 4-3. Clock Timing
4.2 Basic Clock Cycle of the Digital Circuitry
The complete timing of the digital circuitry is derived from one clock. As shown in Figure 4-2 on page 23, this clock cycle TDCLK
is derived from the crystal oscillator (XTO) in combination with a divider.
TDCLK controls the following application relevant parameters:
●Timing of the polling circuit including bit check
●TX bit rate
The clock cycle of the bit check and the TX bit rate depends on the selected bit-rate range (BR_Range) which is defined in
control register 6 (see Table 7-20 on page 36) and XLim which is defined in control register 4 (see Table 7-13 on page 34). This
clock cycle TXDCLK is defined by the following formulas for further reference:
BR_Range ⇒BR_Range 0: TXDCLK = 8 × TDCLK × XLim
BR_Range 1: TXDCLK = 4 × TDCLK × XLim
BR_Range 2: TXDCLK = 2 × TDCLK × XLim
BR_Range 3: TXDCLK = 1 × TDCLK × XLim
fCLK
fXTO
3
-----------=
CLK_ON
(Control register 3)
N_RESET
CLK
VSOUT
VThres_2 = 2.38V (typically)
VThres_1 = 2.3V (typically)
fDCLK
fXTO
16
-----------=
25Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
5. Power Supply
Figure 5-1. Power Supply
The supply voltage range of the ATA5428 is 2.4V to 3.6V or 4.4V to 6.6V.
Pin VS1 is the supply voltage input for the range 2.4V to 3.6V and is used in 1 Li battery applications (3V) using a single lithium
3V cell. Pin VS2 is the voltage input for the range 4.4V to 6.6V (2 Li battery application (6V) and Base-station Application (5V);
in this case, the voltage regulator V_REG1 regulates VS1 to typically 3.25V. If the voltage regulator is active, a blocking
capacitor of 2.2µF has to be connected to VS1.
Pin VAUX is an input for an additional auxiliary voltage supply and can be connected, for example, to an inductive supply
(see Figure 5-6 on page 30). This input can only be used together with a rectifier or as in the application shown in Figure 2.2 on
page 8 and must otherwise be left open.
Pin VSINT is the voltage input for the Microcontoller_Interface and must be connected to the power supply of the
microcontroller. The voltage range of VVSINT is 2.4V to 5.25V (see Figure 5-5 on page 30 and Figure 5-6 on page 30).
AVCC is the internal operation voltage of the RF transceiver and is fed by VS1 via the switch SW_AVCC. AVCC must be
blocked with a 68nF capacitor (see Figure 2-1 on page 7, Figure 2.2 on page 8 and Figure 2-3 on page 9).
DVCC is the internal operation voltage of the digital control logic and is fed by VS1 or VSOUT via the switch SW_DVCC. DVCC
must be blocked on pin DVCC with 68 nF (see Figure 2-1 on page 7, Figure 2.2 on page 8 and Figure 2-3 on page 9).
V_REG2
3.25V typ.
V_Monitor
(2.3V/
2.38V typ.)
V_Monitor
(1.5V typ.)
V_REG1
3.25V typ.
SW_DVCC
Low_Batt
(Status Register
and Reset Logic)
VSOUT_OK
(to XTO and
Reset Logic)
DVCC_OK
(to XTO and
Reset Logic)
SW_VSOUT
VSOUT_EN
VAUX
SW_AVCC
OUT
T5
VS1+
0.55V
typ.
to
T1
R
S
FF1
Q
PWR_ON
VSINT
AVCC_EN
DVCC_OK
OFFCMD
P_On_Aux
(Command via SPI)
(Status register)
R
0
1
0
1
Q
no change
0
1
1
S
0
0
1
1
(Control register 3)
(Control register 1)
AVCC
VSOUT
DVCC
VS2
VS1
IN
EN
OUTIN
EN
and
+
-
≥ 1
≥ 1
26Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
Pin VSOUT is a power supply output voltage for external devices (for example, microcontrollers) and is fed by VS1 via the
switch SW_VSOUT, or by the auxiliary voltage supply VAUX via V_REG2. The voltage regulator V_REG2 regulates VSOUT to
typically 3.25V. If the voltage regulator is active, a blocking capacitor of 2.2µF has to be connected to VSOUT. VSOUT can be
switched off by the VSOUT_EN bit in control register 3 and is then reactivated by conditions found in Figure 5-2 on page 27.
Pin N_RESET is set to low if the voltage VVSOUT at pin VSOUT drops below 2.3V (typically) and can be used as a reset signal for
a connected microcontroller (see Figure 5-3 on page 29 and Figure 5-4 on page 29).
Pin PWR_ON is an input to switch on the transceiver (active high).
Pin T1 to T5 are inputs for push buttons and can also be used to switch on the transceiver (active low).
For current consumption reasons it is recommended to set T1 to T5 to GND, or PWR_ON to VCC only temporarily. Otherwise,
an additional current flows because of a 50kΩ pull-up resistor.
There are two voltage monitors generating the following signals (see Figure 5-1 on page 25):
●DVCC_OK if DVCC > 1.5V typically
●VSOUT_OK if VSOUT > VThres1 (2.3V typically)
●Low_Batt if VSOUT < VThres2 (2.38V typically)
27Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
Figure 5-2. Operation Modes Flow Chart
5.1 OFF Mode
If the power supply (battery) is connected to pin VS1 and/or VS2, and if the voltage on pin VAUX VVAUX < 3.5V (typically), then
the transceiver is in OFF mode. In OFF mode AVCC, DVCC and VSOUT are disabled, resulting in very low power consumption
(IS_OFF is typically 10nA). In OFF mode the transceiver is not programmable via the 4-wire serial interface.
AVCC = VS1
DVCC = VS1
VSOUT = OFF
IDLE Mode
AVCC = VS1
DVCC = VS1
VSOUT = VS1
or V_REG2
TX Mode
AVCC = VS1
DVCC = VS1
VSOUT = VS1
or V_REG2
AVCC = VS1
DVCC = VS1
VSOUT = VS1
or V_REG2
RX Polling Mode
AVCC = VS1
DVCC = VS1
VSOUT = OFF
RX Polling Mode
RX Mode
AVCC = VS1
DVCC = VS1
VSOUT = VS1 VVAUX > VS1 + 0.5V
VVAUX < VS1 + 0.5V
VVAUX > 3.5V (typ)
VVAUX < 3.5V (typ)
IDLE Mode
AVCC = VS1
DVCC = VS1
VSOUT = V_REG2
IDLE Mode
AVCC = OFF
DVCC = OFF
VSOUT = OFF
OFF Mode
AVCC = OFF
DVCC = V_REG2
VSOUT = V_REG2
AUX Mode
Pin PWR_ON = 1 or
Pin T1, T2, T3, T4 or
Pin T5
Pin PWR_ON = 1 or
Pin T1, T2, T3, T4 or
Pin T5 or
Bit AVCC_EN = 1
OPM1 = 0 and OPM0 = 1
OPM1 = 0 and OPM0 = 0
OPM1
0
1
1
OPM0
1
0
1
TX Mode
RX Polling Mode
RX Mode
OPM1 = 1 and OPM0 = 1
or Bit check ok
VSOUT_EN = 0
Bit check ok
OPM1 = 1 and OPM0 = 1
OPM1 = 1 and OPM0 = 0
OPM1 = 1 and OPM0 = 0OPM1 = 0 and OPM0 = 1
VSOUT_EN = 0
Status bit Power_On = 1
or
Event on Pin T1, T2, T3, T4 or T5
Statusbit Power_On = 1
or
Event on Pin T1, T2, T3, T4 or T5
Bit AVCC_EN = 0 and
OFF Command and
Pin PWR_ON = 0 and
Pin T1, T2, T3, T4 and
T5 = 1
Bit AVCC_EN = 0 and OFF Command and
Pin PWR_ON = 0 and
Pin T1, T2, T3, T4 and T5 = 1
28Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
5.2 AUX Mode
The transceiver changes from OFF mode to AUX mode if the voltage at pin VAUX VVAUX > 3.5V (typically). In AUX mode DVCC
and VSOUT are connected to the auxiliary power supply input (VAUX) via the voltage regulator V_REG2. In AUX mode the
transceiver is programmable via the 4-wire serial interface, but no RX or TX operations are possible because AVCC = OFF.
The state transition OFF mode to AUX mode is indicated by an interrupt at pin IRQ and the status bit P_On_Aux = 1.
5.3 IDLE Mode
In IDLE mode AVCC and DVCC are connected to the battery voltage (VS1).
From OFF mode the transceiver changes to IDLE mode if pin PWR_ON is set to 1 or pin T1, T2, T3, T4 or T5 is set to “0”. This
state transition is indicated by an interrupt at pin IRQ and the status bits Power_On = 1 or ST1, ST2, ST3, ST4 or ST5 = 1.
From AUX mode the transceiver changes to IDLE mode by setting AVCC_EN = 1 in control register 1 via the 4-wire serial
interface or if pin PWR_ON is set to “1” or pin T1, T2, T3, T4 or T5 is set to “0”.
VSOUT is either connected to VS1 or to the auxiliary power supply (V_REG2).
If VVAUX < VS1 + 0.5V, VSOUT is connected to VS1. If VVAUX > VS1 + 0.5V, VSOUT is connected to V_REG2 and the status bit
P_On_Aux is set to “1”.
In IDLE mode, the RF transceiver is disabled and the power consumption IS_IDLE is about 230 µA (VSOUT OFF and CLK output
OFF and VS = VS1 = VS2 = 3V). The exact value of this current is strongly dependent on the application and the exact
operation mode, therefore check the section “Electrical Characteristics: General” on page 59 for the appropriate application
case.
Via the 4-wire serial interface a connected microcontroller can program the required parameter and enable the TX, RX polling or
RX mode.
The transceiver can be set back to OFF mode by an OFF command via the 4-wire serial interface (the bit AVCC_EN must be
set to “0”, the input level of pin PWR_ON must be “0” and pin T1, T2, T3, T4 and T5 = 1 before writing the OFF command).
5.4 Reset Timing and Reset Logic
If the transceiver is switched on (OFF mode to IDLE mode, OFF mode to AUX mode) DVCC and VSOUT ramp up as illustrated
in Figure 5-3 on page 29 (AVCC only ramps up if the transceiver is set to the IDLE mode). The internal signal DVCC_RESET
resets the digital control logic and sets the control register to default values.
A voltage monitor generates a low level at pin N_RESET until the voltage at pin VSOUT exceeds 2.38V (typically) and the start-
up time of the XTO has elapsed (amplitude detector, see Figure 4-2 on page 23). After the voltage at pin VSOUT exceeds 2.3V
(typically) and the start-up time of the XTO has elapsed, the output clock at pin CLK is available. Because the enabling of pin
CLK is asynchronous, the first clock cycle may be incomplete.
The status bit Low_Batt is set to “1” if the voltage at pin VSOUT VVSOUT drops below VThres_2 (typically 2.38V). Low_Batt is set to
“0” if VVSOUT exceeds VThres_2 and the status register is read via the 4-wire serial interface or N_RESET is set to low.
If VVSOUT drops below VThres_1 (typically 2.3V), N_RESET is set to low. If bit VSOUT_EN in control register 3 is “1”, a
DVCC_RESET is also generated. If VVSOUT was already disabled by the connected microcontroller by setting bit
VSOUT_EN = 0, no DVCC_RESET is generated.
Note: If VSOUT < VThres_1 (typically 2.3 V) the output of the pin CLK is low, the Microcontroller_Interface is disabled and
the transceiver is not programmable via the 4-wire serial interface.
Table 5-1. Control Register 1
OPM1 OPM0 Function
0 0 IDLE mode
29Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
Figure 5-3. Reset Timing
Figure 5-4. Reset Logic, SR Latch Generates the Hysteresis in the NRESET Signal
N_RESET
VSOUT_EN
(Control Register 3)
LOW_Batt
(Status Register)
DVCC_RESET
VSOUT
VSOUT
DVCC
(AVCC)
VThres_1 = 2.3V (typ)
1.5V (typically)
VThres_2 = 2.38V (typ)
VSOUT > 2.3V and the XTO is running
VSOUT > 2.38V and the XTO is running
≥ 1
and
XTO_OK
LOW_BATT
VSOUT_OK
DVCC_OK
VSOUT_EN
DVCC_RESET
N_RESE
T
and
and
Q
Q
R
S
S
0
0
1
1
R
0
1
0
1
Q
no change
0
1
no change
30Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
5.5 1 Li Battery Application (3V)
The supply voltage range is 2.4V to 3.6V and VAUX is not used.
Figure 5-5. 1 Li Battery Application (3V)
5.6 2 Li Battery Application (6V)
The supply voltage range is 4.4V to 6.6V and VAUX is connected to an inductive supply.
Figure 5-6. 2 Li Battery Application (6V) with Inductive Emergency Supply
VS
IN
OUT
IN
OUT
OUT
IN
IN
VSOUT
VSINT
NRESET
CLK
IRQ
CS
SCK
SDI_TMDI
SDO_TMDO
DVCC
RF Transceiver
ATA5428 ATmega
48/88/168
Microcontroller_Interface
Digital Control
Logic
AVCC
VAUX
VS2
2.4V to 3.6VVS1
DEM_OUT
VS
IN
OUT
IN
OUT
OUT
IN
IN
VSOUT
VSINT
NRESET
CLK
IRQ
CS
SCK
SDI_TMDI
SDO_TMDO
DVCC
RF Transceiver
ATA5428 ATmega
48/88/168
Microcontroller_Interface
Digital Control
Logic
AVCC
VAUX
VS2 4.4V to 6.6V
VS1
DEM_OUT
31Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
6. Microcontroller Interface
The microcontroller interface is a level converter which converts all internal digital signals that are referred to the DVCC voltage
into the voltage used by the microcontroller. Therefore, the pin VSINT has to be connected to the supply voltage of the
microcontroller.
This makes it possible to use the internal voltage regulator/switch at pin VSOUT as in Figure 2-1 on page 7 and Figure 2-3 on
page 9 or to connect the microcontroller and the pin VSINT directly to the supply voltage of the microcontroller as in Figure 2.2
on page 8.
7. Digital Control Logic
7.1 Register Structure
The configuration of the transceiver is stored in RAM cells. The RAM contains a 16 ×8-bit TX/RX data buffer and a 6 ×8-bit
control register and is writable and readable via a 4-wire serial interface (CS, SCK, SDI_TMDI, SDO_TMDO).
The 1 ×8-bit status register is not part of the RAM and is readable via the 4-wire serial interface.
The RAM and the status information are stored as long as the transceiver is in any active mode (DVCC = VS1 or DVCC =
V_REG2) and are lost when the transceiver switches to OFF mode (DVCC =OFF).
After the transceiver is turned on via pin PWR_ON = High, T1 = Low, T2 = Low, T3 = Low, T4 = Low or T5 = Low or the voltage
at pin VAUX VVAUX > 3.5V (typically), the control registers are in the default state.
Figure 7-1. Register Structure
IR1 -FSIR0 OPM1 OPM0 Control Register 1 (ADR 0)
Control Register 2 (ADR 1)
Control Register 3 (ADR 2)
Control Register 4 (ADR 3)
Control Register 5 (ADR 4)
Control Register 6 (ADR 5)
Status Register (ADR 8)
AVCC
_EN
T_
MODE
TX/RX Data Buffer:
16 × 8 Bit
LSBMSB
FR3 FR2 FR0FR1FR6 FR5 FR4 P_
MODE
FR9 FR8
XLimXSleep
FR7FR12 FR11 FR10 VSOUT
_EN
CLK_
ON
ST2 ST1ST5 ST4 ST3 Power_
On
Low_
Batt
P_On
_Aux
Sleep
3
Sleep
1
Sleep
0
Sleep
2
Sleep
4
ASK/
NFSK
Lim_
min5
Lim_
min3
Lim_
min0
Lim_
min1
Lim_
min2
Lim_
min4
BitChk
0
BitChk
1
Lim_
max5
Lim_
max3
Lim_
max0
Lim_
max1
Lim_
max2
Lim_
max4
Baud
0
Baud
1
32Atmel ATA5428 [DATASHEET]
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7.2 TX/RX Data Buffer
The TX/RX data buffer is used to handle the data transfer during RX and TX operations.
7.3 Control Register
To use the transceiver in different applications, it can be configured by a connected microcontroller via the 4-wire serial
interface.
7.3.1 Control Register 1 (ADR 0)
Table 7-1. Control Register 1 (Function of Bit 7 and Bit 6 in RX Mode)
IR1 IR0 Function (RX Mode)
0 0 Pin IRQ is set to “1” if 4 received bytes are in the TX/RX data buffer or a receiving error occurred
0 1 Pin IRQ is set to “1” if 8 received bytes are in the TX/RX data buffer or a receiving error occurred
1 0 Pin IRQ is set to “1” if 12 received bytes are in the TX/RX data buffer or a receiving error occurred (default)
1 1 Pin IRQ is set to “1” if a receiving error occurred
Table 7-2. Control Register 1 (Function of Bit 7 and Bit 6 in TX Mode)
IR1 IR0 Function (TX Mode)
0 0 Pin IRQ is set to “1” if 4 bytes remain in the TX/RX data buffer or the TX data buffer is empty
0 1 Pin IRQ is set to “1” if 8 bytes remain in the TX/RX data buffer or the TX data buffer is empty
1 0 Pin IRQ is set to “1” if 12 bytes remain in the TX/RX data buffer or the TX data buffer is empty (default)
1 1 Pin IRQ is set to “1” if the TX data buffer is empty
Table 7-3. Control Register 1 (Function of Bit 5)
AVCC_EN Function
0(default)
Table 7-4. Control Register 1 (Function of Bit 4)
FS Function (RX Mode, TX Mode)
0Selected frequency 433/868MHz (default)
33Atmel ATA5428 [DATASHEET]
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7.3.2 Control Register 2 (ADR 1)
Table 7-5. Control Register 1 (Function of Bit 2 and Bit 1)
OPM1 OPM0 Function
0 0 IDLE mode (default)
0 1 TX mode
1 0 RX polling mode
1 1 RX mode
Table 7-6. Control Register 1 (Function of Bit 0)
T_MODE Function
0TX and RX function via TX/RX data buffer (default)
1Transparent mode, TX/RX data buffer disabled, TX modulation data stream via pin SDI_TMDI, RX
modulation data stream via pin SDO_TMDO
Table 7-7. Control Register 2 (Function of Bit 7, Bit 6, Bit 5, Bit 4, Bit 3, Bit 2 and Bit 1)
FR6
26FR5
25FR4
24FR3
23FR2
22FR1
21FR0
20Function
0000000FREQ2 = 0
0000001FREQ2 = 1
.......
1011000FREQ2 = 88 (default)
.......
1111111FREQ2 = 127
Note: Tuning of fRF LSBs (total 13 bits), frequency trimming resolution of fRF is fXTO/16384, which is approximately
800Hz (see section “XTO”, Table 4-1 on page 23)
Table 7-8. Control Register 2 (Function of Bit 0 in RX Mode)
P_MODE Function (RX Mode)
0Pin IRQ is set to “1” if the bit check is successful (default)
1No effect on pin IRQ if the bit check is successful
Table 7-9. Control Register 2 (Function of Bit 0 in TX Mode)
P_MODE Function (TX Mode)
0Manchester modulator on (default)
1Manchester modulator off (NRZ mode)
34Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
7.3.3 Control Register 3 (ADR 2)
7.3.4 Control Register 4 (ADR 3)
Table 7-10. Control Register 3 (Function of Bit 7, Bit 6, Bit 5, Bit 4, Bit 3 and Bit 2)
FR12
212 FR11
211 FR10
210 FR9
29FR8
28FR7
27Function
0 0 0 0 0 0 FREQ3 = 0
0 0 0 0 0 1 FREQ3 = 128
0 0 0 0 1 0 FREQ3 = 256
.......
0 1 1 1 1 0 FREQ3 = 3840 (default)
.......
1 1 1 1 1 0 FREQ3 = 7936
1 1 1 1 1 1 FREQ3 = 8064
Note: Tuning of fRF MSBs
Table 7-11. Control Register 3 (Function of Bit 1)
VSOUT_EN Function
0Output voltage power supply for external devices off (pin VSOUT)
1Output voltage power supply for external devices on (default)
Note: This bit is set to “1” if the bit check is OK (RX_Polling, RX mode), an event at pin T1, T2, T3, T4 or T5 occurs
or the bit Power_On in the status register is “1”.
Setting VSOUT_EN = 0 in AUX mode is not allowed
Table 7-12. Control Register_3 (Function of Bit 0)
CLK_ON Function
0Clock output off (pin CLK)
1Clock output on (default)
Note: This bit is set to “1” if the bit check is OK (RX_Polling, RX mode), an event at pin T1, T2, T3, T4 or T5 occurs or
the bit Power_On in the status register is “1”.
Table 7-13. Control Register 4 (Function of Bit 7)
ASK_NFSK Function (TX Mode, RX Mode)
0FSK mode (default)
1ASK mode
35Atmel ATA5428 [DATASHEET]
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7.3.5 Control Register 5 (ADR 4)
Table 7-14. Control Register 4 (Function of Bit 6, Bit 5, Bit 4, Bit 3 and Bit 2)
Sleep4
24Sleep3
23Sleep2
22Sleep1
21Sleep0
20
Function (RX Mode)
Sleep
(TSleep = Sleep × 1024 × TDCLK × XSleep)
0 0 0 0 0 0
0 0 0 0 1 1
.....
01010
10
(TSleep = 10 × 1024 × TDCLK × XSleep)
(default)
.....
11111 31
Table 7-15. Control Register 4 (Function of Bit 1)
XSleep Function
0 XSleep = 1; extended TSleep off (default)
1 XSleep = 8; extended TSleep on
Table 7-16. Control Register 4 (Function of Bit 0)
XLim Function
0 XLim = 1; extended TLim_min, TLim_max off (default)
1 XLim = 2; extended TLim_min, TLim_max on
Table 7-17. Control Register 5 (Function of Bit 7 and Bit 6)
BitChk1 BitChk0 Function
0 0 NBit-check = 0 (0 bits checked during bit check)
0 1 NBit-check = 3 (3 bits checked during bit check) (default)
1 0 NBit-check = 6 (6 bits checked during bit check)
1 1 NBit-check = 9 (9 bits checked during bit check)
36Atmel ATA5428 [DATASHEET]
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7.3.6 Control Register 6 (ADR 5)
Table 7-18. Control Register 5 (Function of Bit 5, Bit 4, Bit 3, Bit 2, Bit 1 and Bit 0 in RX Mode)
Lim_min5 Lim_min4 Lim_min3 Lim_min2 Lim_min1 Lim_min0
Function (RX Mode)
Lim_min
(Lim_min < 10 are not applicable)
(TLim_min = Lim_min × TXDCLK)
0 0 1 0 1 0 10
0 0 1 0 1 1 11
. . . . . .
0 1 0 0 0 0
16
(TLim_min = 16 × TXDCLK)
(default)
. . . . . .
1 1 1 1 1 1 63
Table 7-19. Control Register 5 (Function of Bit 5, Bit 4, Bit 3, Bit 2, Bit 1 and Bit 0 in TX Mode)
Lim_min5 Lim_min4 Lim_min3 Lim_min2 Lim_min1 Lim_min0
Function (TX Mode) Lim_min
(Lim_min < 10 are not applicable)
(TX_Bitrate = 1/((Lim_min + 1) × TXDCLK × 2)
0 0 1 0 1 0 10
0 0 1 0 1 1 11
. . . . . .
0 1 0 0 0 0
16
(TX_Bitrate = 1/((16 + 1) × TXDCLK × 2)
(default)
. . . . . .
1 1 1 1 1 1 63
Table 7-20. Control Register 6 (Function of Bit 7 and Bit 6)
Baud1 Baud0 Function
0 0 Bit-rate range 0 (B0) 1.0 Kbit/s to 2.5 Kbit/s;
TXDCLK = 8 × TDCLK × XLim
0 1 Bit-rate range 1 (B1) 2.0 Kbit/s to 5.0 Kbit/s;
TXDCLK = 4 × TDCLK × XLim
1 0 Bit-rate range 2 (B2) 4.0 Kbit/s to 10.0 Kbit/s;
TXDCLK = 2 × TDCLK × XLim; (default)
1 1
Bit-rate range 3 (B3) 8.0 Kbit/s to 20.0 Kbit/s;
TXDCLK = 1 × TDCLK × XLim
Note that the receiver does not work with >10 Kbit/s in ASK mode
37Atmel ATA5428 [DATASHEET]
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7.4 Status Register
The status register indicates the current status of the transceiver and is readable via the 4-wire serial interface. Setting
Power_On or P_On_Aux or an event on ST1, ST2, ST3, ST4 or ST5 is indicated by an IRQ.
Reading the status register resets the bits Power_On, Low_Batt, P_On_Aux and the IRQ.
7.4.1 Status Register (ADR 8)
Table 7-21. Control Register 6 (Function of Bit 5, Bit 4, Bit 3, Bit 2, Bit 1 and Bit 0)
Lim_max5 Lim_max4 Lim_max3 Lim_max2 Lim_max1 Lim_max0
Function Lim_max
(Lim_max < 12 is not Applicable)
(TLim_max = (Lim_max – 1) × TXDCLK)
001100 12
001101 13
......
011100
28
(TLim_max = (28 – 1) × TXDCLK)
(default)
......
111111 63
Table 7-22. Status Register
Status Bit Function
ST5
Status of pin T5
Pin T5 = 0 →ST5 = 1
Pin T5 = 1 →ST5 = 0
(see Figure 7-3 on page 39)
ST4
Status of pin T4
Pin T4 = 0 →ST4 = 1
Pin T4 = 1 →ST4 = 0
(see Figure 7-3 on page 39)
ST3
Status of pin T3
Pin T3 = 0 →ST3 = 1
Pin T3 = 1 →ST3 = 0
(see Figure 7-3 on page 39)
ST2
Status of pin T2
Pin T2 = 0 →ST2 = 1
Pin T2 = 1 →ST2 = 0
(see Figure 7-3 on page 39)
ST1
Status of pin T1
Pin T1 = 0 →ST1 = 1
Pin T1 = 1 →ST1 = 0
(see Figure 7-3 on page 39)
38Atmel ATA5428 [DATASHEET]
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7.5 Pin Tn
To switch the transceiver from OFF to IDLE mode, pin Tn must be set to “0” (maximum 0.2 ×VVS2) for at least TTn_IRQ (see
Figure 7-2). The transceiver recognizes the negative edge, sets pin N_RESET to low and switches on DVCC, AVCC and the
power supply for external devices VSOUT.
If VDVCC exceeds 1.5V (typically) and the XTO is settled, the digital control logic is active and sets the status bit STn to “1” and
an interrupt is issued (TTn_IRQ).
After the voltage on pin VSOUT exceeds 2.3V (typically) and the start-up time of the XTO is elapsed, the output clock on pin
CLK is available. Because the enabling of pin CLK is asynchronous, the first clock cycle may be incomplete. N_RESET is set to
high if VVSOUT exceeds 2.38V (typically) and the XTO is settled.
Figure 7-2. Timing Pin Tn, Status Bit STn
Power_On
Indicates that the transceiver was woken up by pin PWR_ON (rising edge on
pin PWR_ON). During Power_On = 1, the bits VSOUT_EN and CLK_ON in
control register 3 are set to “1”. (see Figure 7-4 on page 40)
Low_Batt Indicates that output voltage on pin VSOUT is too low
(VVSOUT < 2.38V typically), (see Figure 7-5 on page 41)
P_On_Aux
Indicates that the auxiliary supply voltage on pin VAUX is high enough to
operate.
State transition:
a) OFF mode →AUX mode (see Figure 5-2 on page 27)
b) IDLE mode (VSOUT = VS1) →IDLE mode (VSOUT = V_REG2)
(see Figure 7-6 on page 42)
Table 7-22. Status Register (Continued)
Status Bit Function
STn
(Status register)
IRQ
CLK
N_RESET
DVCC, AVCC
VSOUT
Tn
IDLE
Mode
OFF
Mode
VThres_2 = 2.38V (typ)
VThres_1 = 2.3V (typ)
TTn_IRQ
1.5V (typ)
39Atmel ATA5428 [DATASHEET]
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If the transceiver is in any active mode (IDLE, AUX, TX, RX, RX_Polling), an integrated debounce logic is active. If there is an
event on pin Tn a debounce counter is set to 0 (T = 0) and started. The status is updated, an interrupt is issued and the
debounce counter is stopped after reaching the counter value T = 8195 × TDCLK.
An event on the same key input before reaching T = 8195 × TDCLK stops the debounce counter. An event on an other key input
before reaching T = 8195 × TDCLK resets and restarts the debounce counter.
While the debounce counter is running, the bits VSOUT_EN and CLK_ON in control register 3 are set to “1”.
The interrupt is deleted after reading the status register or executing the command Delete_IRQ.
If pin Tn is not used, it can be left open because of an internal pull-up resistor (typically 50kΩ).
Figure 7-3. Timing Flow Pin Tn, Status Bit STn
IDLE Mode or
AUX Mode or
TX Mode or
RX Polling Mode or
RX Mode
Stop debounce counter
STn = 1
IRQ = 1
Stop debounce counter
STn = 0
IRQ = 1
Stop debounce counter
Tn = STn ? Pin Tn = 0 ?
T = 0
Start debounce counter
Event on Pin Tn ?
Event on Pin Tn ?
N
NN
N
Y
Y
Y
Y
Y
N
T = 8195 × T ?
40Atmel ATA5428 [DATASHEET]
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7.6 Pin PWR_ON
To switch the transceiver from OFF to IDLE mode, pin PWR_ON must be set to “1” (minimum 0.8 ×VVS2) for at least TPWR_ON
(see Figure 7-4). The transceiver recognizes the positive edge, sets pin N_RESET to low, and switches on DVCC, AVCC and
the power supply for external devices VSOUT.
If VDVCC exceeds 1.5V (typically) and the XTO is settled, the digital control logic is active and sets the status bit Power_On to “1”
and an interrupt is issued (TPWR_ON_IRQ_1).
After the voltage on pin VSOUT exceeds 2.3V (typically) and the start-up time of the XTO is elapsed the output clock on pin CLK
is available. Because the enabling of pin CLK is asynchronous, the first clock cycle may be incomplete. N_RESET is set to high
if VVSOUT exceeds 2.38V (typically) and the XTO is settled.
If the transceiver is in any active mode (IDLE, AUX, RX, RX_Polling, TX), a positive edge on pin PWR_ON sets Power_On to
“1” (after TPWR_ON_IRQ_2). The state transition Power_On 0 → 1 generates an interrupt. If Power_On is still “1” during the positive
edge on pin PWR_ON no interrupt is issued. Power_On and the interrupt are deleted after reading the status register.
During Power_On = 1, the bits VSOUT_EN and CLK_ON in control register 3 are set to “1”.
Note: It is not possible to set the transceiver to OFF mode by setting pin PWR_ON to “0”. If pin PWR_ON is not used, it
must be connected to GND.
Figure 7-4. Timing Pin PWR_ON, Status Bit Power_On
Power_ON
(Status register)
IRQ
CLK
N_RESET
DVCC, AVCC
VSOUT
PWR_ON
OFF
Mode
IDLE
Mode
IDLE, AUX, RX, RX Polling, TX
Mode
TPWR_ON > TPWR_ON_IRQ_2
TPWR_ON > TPWR_ON_IRQ_1
TPWR_ON_IRQ_2
TPWR_ON_IRQ_1
1.5V (typ)
VThres_2 = 2.38V (typ)
VThres_1 = 2.V
(typ)
41Atmel ATA5428 [DATASHEET]
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7.7 Low Battery Indicator
The status bit Low_Batt is set to “1” if the voltage VVSOUT on pin VSOUT drops below 2.38V (typically).
Low_Batt is set to “0” if VVSOUT exceeds VThres_2 and the status register is read via the 4-wire serial interface (see Figure 5-3 on
page 29).
Figure 7-5. Timing Status Bit Low_Batt
7.8 Pin VAUX
To switch the transceiver from OFF to AUX mode, the voltage VVAUX on pin VAUX must exceed 3.5V (typically) (see Figure 7-6
on page 42). If VVAUX exceeds 2V (typically) pin N_RESET is set to low, and DVCC and the power supply for external devices
VSOUT are switched on.
If VVAUX exceeds 3.5V (typically) the status bit P_On_Aux is set to “1” and an interrupt is issued.
After the voltage on pin VSOUT exceeds 2.3V (typically) and the start-up time of the XTO is elapsed, the output clock on pin
CLK is available. Because the enabling of pin CLK is asynchronous, the first clock cycle may be incomplete. N_RESET is set to
high if VVSOUT exceeds 2.38V (typically) and the XTO is settled.
If the transceiver is in any active mode (IDLE, TX, RX, RX_Polling), a positive edge on pin VAUX and VVAUX > VS1 + 0.5V sets
P_On_Aux to “1”. The state transition P_On_Aux 0 → 1 generates an interrupt. If P_On_Aux is still “1” during the positive edge
on pin VAUX no interrupt is issued. P_On_Aux and the interrupt are deleted after reading the status register.
IDLE, AUX, TX, RX
or
RX Polling Mode
Read Status Register
VVSOUT < 2.38V (typ)
?
Y
N
Low_Batt = 1
42Atmel ATA5428 [DATASHEET]
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Figure 7-6. Timing Pin VAUX, Status Bit P_On_Aux
8. Transceiver Configuration
The configuration of the transceiver takes place via a 4-wire serial interface (CS, SCK, SDI_TMDI, SDO_TMDO) and is
organized in 8-bit units. The configuration is initiated with an 8-bit command. While shifting the command into pin SDI_TMDI,
the number of bytes in the TX/RX data buffer are available on pin SDO_TMDO. The read and write commands are followed by
one or more 8-bit data units. Each 8-bit data transmission begins with the MSB. The serial interface is in the reset state if the
level on pin CS = Low.
8.1 Command: Read TX/RX Data Buffer
During a RX operation, the user can read the received bytes in the TX/RX data buffer successively.
Figure 8-1. Read TX/RX Data Buffer
P_ON_AUX
(Status register)
IRQ
CLK
N_RESET
DVCC
VSOUT
VAUX
OFF
Mode
AUX
Mode
IDLE, TX, RX, RX polling
Mode
2.0V (typ)
3.5V (typ)
VThres_2 = 2.38V (typ)
VThres_1 = 2.3V (typ)
VVAUX > VS1 + 0.5V (typ) VVAUX > VS1 + 0.5V (typ)
SCK
CS
SDO_TMDO
SDI_TMDI
RX Data Byte 1RX Data Byte 1No. Bytes in the TX/RX Data Buffer
Command: Read TX/RX Data Buffer X
MSB MSBLSB LSB LSBMSB
X
43Atmel ATA5428 [DATASHEET]
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8.2 Command: Write TX/RX Data Buffer
During a TX operation the user can write the bytes in the TX/RX data buffer successively. An echo of the command and the TX
data bytes are provided for the microcontroller on pin SDO_TMDO.
Figure 8-2. Write TX/RX Data Buffer
8.3 Command: Read Control/Status Register
The control and status registers can be read individually or successively.
Figure 8-3. Read Control/Status Register
8.4 Command: Write Control Register
The control registers can be written individually or successively. An echo of the command and the data bytes are provided for
the microcontroller on pin SDO_TMDO.
Figure 8-4. Write Control Register
8.5 Command: OFF Command
If AVCC_EN in control register 1 is “0”, the input level on pin PWR_ON is low and on the key inputs Tn is high, then the OFF
command sets the transceiver in the OFF mode.
Figure 8-5. OFF Command
SCK
CS
SDO_TMDO
SDI_TMDI
TX Data Byte 1Write TX/RX Data BufferNo. Bytes in the TX/RX Data Buffer
Command: Write TX/RX Data Buffer TX Data Byte 1
MSB MSBLSB LSB LSBMSB
TX Data Byte 2
SCK
CS
SDO_TMDO
SDI_TMDI
Data C/S Register X Data C/S Register YNo. Bytes in the TX/RX Data Buffer
Command: Read C/S Register X
MSB MSBLSB LSB LSBMSB
Command: Read C/S Register ZCommand: Read C/S Register Y
SCK
CS
SDO_TMDO
SDI_TMDI
Write Control Register X Data Control Register XNo. Bytes in the TX/RX Data Buffer
Command: Write Control Register X
MSB MSBLSB LSB LSBMSB
Command: Write Control Register YData Control Register X
SCK
CS
SDO_TMDO
SDI_TMDI
No. Bytes in the TX/RX Data Buffer
Command: OFF Command
LSBMSB
44Atmel ATA5428 [DATASHEET]
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8.6 Command: Delete IRQ
The delete IRQ command sets pin IRQ to low.
Figure 8-6. Delete IRQ
8.7 Command Structure
The three most significant bits of the command (bit 5 to bit 7) indicate the command type. Bit 0 to bit 4 describe the target
address when reading or writing a control or status register. In all other commands bit 0 to bit 4 have no effect and should be set
to “0” for compatibility with future products.
8.8 4-wire Serial Interface
The 4-wire serial interface consists of the Chip Select (CS), the Serial Clock (SCK), the Serial Data Input (SDI_TMDI) and the
Serial Data Output (SDO_TMDO). Data is transmitted/received bit by bit in synchronization with the serial clock.
Note: If the output level on pin N_RESET is low, no data communication with the microcontroller is possible.
When CS is low and the transparent mode is inactive (T_MODE = 0), SDO_TMDO is in a high impedance state. When CS is
low and the transparent mode is active (T_MODE = 1), the RX data stream is available on pin SDO_TMDO.
SCK
CS
SDO_TMDO
SDI_TMDI
No. Bytes in the TX/RX Data Buffer
Command: Delete IRQ
LSBMSB
Table 8-1. Command Structure
Command
MSB LSB
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Read TX/RX data buffer 0 0 0 x x x x x
Write TX/RX data buffer 0 0 1 x x x x x
Read control/status register 010A4 A3 A2 A1 A0
Write control register 011A4 A3 A2 A1 A0
OFF command 1 0 0 X X X X X
Delete IRQ 1 0 1 X X X X X
Not used 1 1 0 X X X X X
Not used 1 1 1 X X X X X
45Atmel ATA5428 [DATASHEET]
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Figure 8-7. Serial Timing
9. Operation Modes
9.1 RX Operation
The transceiver is set to RX operation with the bits OPM0 and OPM1 in control register 1.
The transceiver is designed to consume less than 1mA in RX operation while remaining sensitive to signals from a
corresponding transmitter. This is achieved via the polling circuit. This circuit enables the signal path periodically for a short
time. During this time the bit-check logic verifies the presence of a valid transmitter signal. Only if a valid signal is detected does
the transceiver remain active and transfer the data to the connected microcontroller. This transfer takes place either via the
TX/RX data buffer or via the pin SDO_TMDO. When there is no valid signal present, the transceiver is in sleep mode most of
the time, resulting in low current consumption. This condition is called RX polling mode. A connected microcontroller can be
disabled during this time.
All relevant parameters of the polling logic can be configured by the connected microcontroller. This flexibility enables the user
to meet the specifications in terms of current consumption, system response time, data rate, etc.
In RX mode the RF transceiver is enabled permanently and the bit-check logic verifies the presence of a valid transmitter signal.
When a valid signal is detected the transceiver transfers the data to the connected microcontroller. This transfer take place
either via the TX/RX data buffer or via the pin SDO_TMDO.
MSB MSB-1
LSBMSB MSB-1
X XXX
XX
CS
SCK
SDO_TMDO
SDI_TMDI
TCS_disable
TSCK_setup2
TSCK_hold
TSCK_setup1
TCycle
X can be either ViL or ViH
TCS_setup
TOut_enable TOut_delay
TSetup
THold
TOut_disable
Table 9-1. Control Register 1
OPM1 OPM0 Function
1 0 RX polling mode
1 1 RX mode
46Atmel ATA5428 [DATASHEET]
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9.1.1 RX Polling Mode
When the transceiver is in RX polling mode it stays in a continuous cycle of three different modes. In sleep mode the RF
transceiver is disabled for the time period TSleep while consuming low current of IS = IIDLE_X. During the start-up period,
TStartup_PLL and TStartup_Sig_Proc, all signal processing circuits are enabled and settled. In the following bit-check mode, the
incoming data stream is analyzed bit by bit to see if it is a valid transmitter signal. If no valid signal is present, the transceiver is
set back to sleep mode after the period TBit-check. This period varies check by check as it is a statistical process. An average
value for TBit-check is given in the electrical characteristics. During TStartup_PLL the current consumption is IS = IStartup_PLL_X. During
TStartup_Sig_Proc and TBit-check the current consumption is IS = IRX_X. The condition of the transceiver is indicated on pin
RX_ACTIVE (see Figure 9-1 on page 47 and Figure 9-2 on page 48). The average current consumption in RX polling mode IP is
different in 1 Li battery application (3V), 2 Li battery application (6V) or Base-station Application (5V). To calculate IP the index X
must be replaced by VS1,VS2 in 1 Li battery application (3V), VS2 in 2 Li battery application (6V) or VS2,VAUX in Base-station
Application (5V) (see section “Electrical Characteristics: General” on page 59).
To save current it is recommended that CLK and VVSOUT be disabled during RX polling mode. IP does not include the current of
the Microcontroller_Interface, IVSINT, or the current of an external device connected to pin VSOUT (for example, microcontroller).
If CLK and/or VSOUT is enabled during RX polling mode the current consumption is calculated as follows:
During TSleep, TStartup_PLL and TStartup_Sig_Proc, the transceiver is not sensitive to a transmitter signal. To guarantee the reception of
a transmitted command, the transmitter must start the telegram with an adequate preburst. The required length of the
preburst, TPreburst, depends on the polling parameters TSleep, TStartup_PLL, TStartup_Sig_Proc and TBit-check. Thus, TBit-check depends on
the actual bit rate and the number of bits (NBit-check) to be tested.
9.1.2 Sleep Mode
The length of period TSleep is defined by the 5-bit word sleep in control register 4, the extension factor XSleep defined by the bit
XSleep in control register 4, and the basic clock cycle TDCLK. It is calculated to be:
In US and European applications, the maximum value of TSleep is about 38ms if XSleep is set to 1 (which is done by setting the bit
XSleep in control register 4 to “0”). The time resolution is about 1.2ms in that case. The sleep time can be extended to about
300ms by setting XSleep to 8 (which is done by setting XSleep in control register 4 to “1”), the time resolution is then about 9.6ms.
9.1.3 Start-up Mode
During TStartup_PLL the PLL is enabled and starts up. If the PLL is locked, the signal processing circuit starts up (TStartup_Sig_Proc).
After the start-up time all circuits are in stable condition and ready to receive.
IP
IIDLE_X TSleep IStartup_PLL_X T×Startup_PLL IRX_X TStartup_Sig_Proc TBitcheck
+()×++×
TSleep TStartup_PLL TStartup_Sig_Proc TBit_check
++ +
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------=
IS_Poll IPIVSINT IEXT
++=
TPreburst TSleep TStartup_PLL TStartup_Sig_Proc TBit_check
++ +≥
TSleep Sleep 1024 TDCLK XSleep
×××=
47Atmel ATA5428 [DATASHEET]
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Figure 9-1. Flow Chart Polling Mode/RX Mode (T_MODE = 0, Transparent Mode Inactive)
Start RX Mode
Start RX Polling Mode
Start-up PLL:
The PLL is enabled and locked.
Output level on pin RX_ACTIVE ⇒ High; IS = IStartup_PLL_X; IStartup_PLL
Start-up signal processing:
The signal processing circuit are enabled.
Output level on pin RX_ACTIVE ⇒ High; IS = IRX_X; TStartup_Sig_proc
The incomming data stream is analyzed. If the timing indicates a valid transmitter signal,
the control bits VSOUT_EN, CLK_ON and OPM0 are set to 1 and the transceiver is set to
receiving mode. Otherwise it is set to Sleep mode or to Start_up mode.
Output level on pin RX_ACTIVE ⇒ High
Bit-check mode:
Sleep: Defined by bits Sleep 0 to Sleep 4 in Control
Register 4
798.5 × TDCLK (typ)TStartup_PLL:
(BR_Range 0)
Is defined by the selected baud rate range and
TDCLK .The baud-rate range is defined by bit
Baud 0 and Baud 1 in Control Register 6.
If the bit check is ok, TBit-check depends on the
number of bits to be checked (NBit-check) and
on the utilized data rate.
882 × TDCLK (BR_Range 1)498 × TDCLK (BR_Range 2)306 × TDCLK (BR_Range 3)210 × TDCLK
TStartup_Sig_Proc:
Defined by bit XSleep in Control register 4
Basic clock cycle
TDCLK:
XSleep:
Depends on the result of the bit check.TBit-check:
All circuits for analog signal processing are disabled. Only XTO and Polling logic is enabled.
Output level on pin RX_ACTIVE ⇒ Low; IS = IIDLE_X
TSleep = Sleep × 1024 × TDCLK × XSleep
Sleep mode:
Start-up mode:
P_MODE = 0
?
Bit check
OK ?
Set IRQ
NO
YES
YES
YES
YES
NO
NO
NO
Set VSOUT_EN = 1
Set CLK_ON = 1
Set OPM0 = 1
TSLEEP = 0
?
OPM0 = 1
?
IS = IRX_X; TBit-check
The incomming data stream is passed via the TX/RX Data Buffer to the connected
microcontroller. If an bit error occurs the transceiver is set back to Start-up mode.
Output level on pin RX_ACTIVE ⇒ High
Receiving mode:
Bit error ?
Start bit
detected ?
YES
YES
NO
NO
RX data stream is
written into the TX/RX
Data Buffer
IS = IRX_X
If the bit check fails, the average time period for
that check despends on the selected bit-rate
range and on TXDCLK. The bit-rate range is
defined by bit Baud 0 and Baud 1 in Control
Register 6.
If the transceiver detects a bit errror after a
successful bit check and before the start bit is
detected pin IRQ will be set to high (only if
P_MODE = 0) and the transceiver is set back to
start-up mode.
48Atmel ATA5428 [DATASHEET]
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Figure 9-2. Flow Chart Polling Mode/RX Mode (T_MODE = 1, Transparent Mode Active)
Start RX Mode
Start RX Polling Mode
Start-up PLL:
The PLL is enabled and locked.
Output level on pin RX_ACTIVE ⇒ High; IS = IStartup_PLL_X; IStartup_PLL
Start-up signal processing:
The signal processing circuit are enabled.
Output level on pin RX_ACTIVE ⇒ High; IS = IRX_X; TStartup_Sig_proc
The incomming data stream is analyzed. If the timing indicates a valid transmitter signal,
the control bits VSOUT_EN, CLK_ON and OPM0 are set to 1 and the transceiver is set to
receiving mode. Otherwise the transceiver is set to Sleep mode
(if OPM0 = 0 and TSleep > 0) or stays in Bit-check mode.
Output level on pin RX_ACTIVE ⇒ High
Bit-check mode:
Sleep: Defined by bits Sleep 0 to Sleep 4 in Control
Register 4
798.5 × TDCLK (typ)TStartup_PLL:
(BR_Range 0)
Is defined by the selected baud rate range and
TDCLK .The baud-rate range is defined by bit
Baud 0 and Baud 1 in Control Register 6.
If the bit check is ok, TBit-check depends on the
number of bits to be checked (NBit-check) and
on the utilized data rate.
882 × TDCLK (BR_Range 1)498 × TDCLK (BR_Range 2)306 × TDCLK (BR_Range 3)210 × TDCLK
TStartup_Sig_Proc:
Defined by bit XSleep in Control register 4
Basic clock cycle
TDCLK:
XSleep:
Depends on the result of the bit check.TBit-check:
All circuits for analog signal processing are disabled. Only XTO and Polling logic is enabled.
Output level on pin RX_ACTIVE ⇒ Low; IS = IIDLE_X
TSleep = Sleep × 1024 × TDCLK × XSleep
Sleep mode:
Start-up mode:
Bit check
OK ?
NO YES
YES
YES
NO
NO
Set VSOUT_EN = 1
Set CLK_ON = 1
Set OPM0 = 1
TSLEEP = 0
?
OPM0 = 1
?
IS = IRX_X; TBit-check
The incomming data stream is passed via PIN SDO_TMDO to the connected
microcontroller. If an bit error occurs the transceiver is not set back to Start-up mode.
Output level on pin RX_ACTIVE ⇒ High
Receiving mode:
Level on pin
CS = Low ?
YES
NO
RX data stream
available on pin
SDO_TMDO
IS = IRX_X
If the bit check fails, the average time period for
that check despends on the selected bit-rate
range and on TXDCLK. The bit-rate range is
defined by bit Baud 0 and Baud 1 in Control
Register 6.
If in FSK mode the datastream is interrupted the
FSK-Demodulator-PLL tends to lock out and is
further not able to lock in, even there is a valid
data stream available.
In this case the transceiver must be set back to
IDLE mode.
49Atmel ATA5428 [DATASHEET]
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9.1.4 Bit-check Mode
In bit-check mode the incoming data stream is examined to distinguish between a valid signal from a corresponding transmitter
and signals due to noise. This is done by subsequent time frame checks where the distance between 2 signal edges are
continuously compared to a programmable time window. The maximum count of this edge-to-edge test before the transceiver
switches to receiving mode is also programmable.
9.1.5 Configuration of the Bit Check
Assuming a modulation scheme that contains two edges per bit, two time frame checks verify one bit. This is valid for
Manchester, Bi-phase and most other modulation schemes. The maximum count of bits to be checked can be set to 0, 3, 6 or 9
bits via the variable NBit-check in control register 5. This implies 0, 6, 12 and 18 edge-to-edge checks, respectively. If NBit-check is
set to a higher value, the transceiver is less likely to switch to receiving mode due to noise. In the presence of a valid transmitter
signal, the bit check takes less time if NBit-check is set to a lower value. In RX polling mode, the bit-check time is not dependent on
NBit-check if no valid signal is present. Figure 9-3 shows an example where three bits are tested successfully.
Figure 9-3. Timing Diagram for Complete Successful Bit Check (Number of Checked Bits: 3)
As seen in Figure 9-4, the time window for the bit check is defined by two separate time limits. If the edge-to-edge time tee is in
between the lower bit-check limit TLim_min and the upper bit-check limit TLim_max, the check will be continued. If tee is smaller than
limit TLim_min or exceeds TLim_max, the bit check will be terminated and the transceiver switches to sleep mode.
Figure 9-4. Valid Time Window for Bit Check
Bit check mode
Bit check ok
Start-up mode Receiving mode
1/2 Bit 1/2 Bit 1/2 Bit 1/2 Bit1/2 Bit 1/2 Bit
RX_ACTIVE
Demod_Out
Bit check
TStartup_Sig_Proc TBit-check
Demod_Out
1/fSig
tee
TLim_min
TLim_max
50Atmel ATA5428 [DATASHEET]
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For the best noise immunity, use of a low span between TLim_min and TLim_max is recommended. This is achieved using a fixed
frequency at a 50% duty cycle for the transmitter preburst: a “11111...” or a “10101...” sequence in Manchester or Bi-phase is a
good choice. A good compromise between sensitivity and susceptibility to noise regarding the expected edge-to-edge time, tee,
is a time window of ±38%; to get the maximum sensitivity the time window should be ±50% and then NBit-check ≥ 6. Using
preburst patterns that contain various edge-to-edge time periods, the bit-check limits must be programmed according to the
required span.
The bit-check limits are determined by means of the formula below:
TLim_min = Lim_min ×TXDCLK
TLim_max = (Lim_max -1) ×TXDCLK
Lim_min is defined by the bits Lim_min 0 to Lim_min 5 in control register 5.
Lim_max is defined by the bits Lim_max 0 to Lim_max 5 in control register 6.
Using the above formulas, Lim_min and Lim_max can be determined according to the required TLim_min, TLim_max and TXDCLK.
The time resolution defining TLim_min and TLim_max is TXDCLK. The minimum edge-to-edge time tee is defined in the section
“Receiving Mode” on page 52. The lower limit should be set to Lim_min ≥ 10. The maximum value of the upper limit is
Lim_max = 63.
Figure 9-5, Figure 9-6 on page 51, and Figure 9-7 on page 51 illustrate the bit check for the bit-check limits Lim_min = 14 and
Lim_max = 24. The signal processing circuits are enabled during TStartup_PLL and TStartup_Sig_Proc. The output of the ASK/FSK
demodulator (Demod_Out) is undefined during that period. When the bit check becomes active, the bit-check counter is clocked
with the cycle TXDCLK.
Figure 9-5 shows how the bit check proceeds if the bit-check counter value CV_Lim is within the limits defined by Lim_min and
Lim_max at the occurrence of a signal edge. In Figure 9-6 on page 51 the bit check fails because the value CV_Lim is lower
than the limit Lim_min. The bit check also fails if CV_Lim reaches Lim_max. This is illustrated in Figure 9-7 on page 51.
Figure 9-5. Timing Diagram During Bit Check
Bit check okBit check ok
Bit check modeStart-up mode
1/2 Bit 1/2 Bit1/2 Bit
RX_ACTIVE
(Lim_min = 14, Lim_max = 24)
Demod_Out
Bit-check counter
Bit check
TStartup_Sig_Proc TBit-check
TXDCLK
123456781234567891011121314151617181234567891011012131415 1 2 3 4 5 67
51Atmel ATA5428 [DATASHEET]
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Figure 9-6. Timing Diagram for Failed Bit Check (Condition CV_Lim < Lim_min)
Figure 9-7. Timing Diagram for Failed Bit Check (Condition: CV_Lim ≥ Lim_max)
9.1.6 Duration of the Bit Check
If no transmitter is present during the bit check, the output of the ASK/FSK demodulator delivers random signals. The bit check
is a statistical process and TBit-check varies for each check. Therefore, an average value for TBit-check is given in the electrical
characteristics. TBit-check depends on the selected bit-rate range and on TXDCLK. A higher bit-rate range causes a lower value for
TBit-check, resulting in a lower current consumption in RX polling mode.
In the presence of a valid transmitter signal, TBit-check is dependent on the frequency of that signal, fSignal, and the count of the
bits, NBit-check. A higher value for NBit-check therefore results in a longer period for TBit-check, requiring a higher value for the
transmitter pre-burst, TPreburst.
Start-up mode
TSleep
TBit_check
TStartup_Sig_Proc
Bit check mode Sleep mode
1/2 Bit
RX_ACTIVE
Demod_Out
Bit-check counter
Bit check
(Lim_min = 14, Lim_max = 24)
Bit check failed (CV_Lim < Lim_min)
12345678123456789101112 00
Start-up mode
TSleep
TBit_check
TStartup_Sig_Proc
Bit check mode Sleep mode
1/2 Bit
RX_ACTIVE
Demod_Out
Bit-check counter
Bit check
(Lim_min = 14, Lim_max = 24)
Bit check failed (CV_Lim < Lim_min)
12345678123456789101112
00
131415161718192021222324
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9.1.7 Receiving Mode
If the bit check was successful for all bits specified by NBit-check, the transceiver switches to receiving mode. To activate a
connected microcontroller, the bits VSOUT_EN and CLK_ON in control register 3 are set to “1”. An interrupt is issued at pin IRQ
if the control bits T_MODE = 0 and P_MODE = 0.
If the transparent mode is active (T_MODE = 1) and the level on pin CS is low (no data transfer via the serial interface), the RX
data stream is available on pin SDO_TMDO (Figure 9-8).
Figure 9-8. Receiving Mode (TMODE = 1)
If the transparent mode is inactive (T_MODE = 0), the received data stream is buffered in the TX/RX data buffer (see Figure 9-
9 on page 53). The TX/RX data buffer is only usable for Manchester and Bi-phase coded signals. It is always possible to
transfer the data from the data buffer via the 4-wire serial interface to a microcontroller (see Figure 8-1 on page 42).
Buffering of the data stream:
After a successful bit check, the transceiver switches from bit-check mode to receiving mode. In receiving mode the TX/RX data
buffer control logic is active and examines the incoming data stream. This is done, as in the bit check, by subsequent time frame
checks where the distance between two edges is continuously compared to a programmable time window as illustrated in
Figure 9-9 on page 53. Only two time differences between two edges in Manchester and Bi-phase coded signals are valid
(T and 2T).
The limits for T are the same as used for the bit check. They can be programmed in control register 5 and 6 (Lim_min,
Lim_max).
The limits for 2T are calculated as follows:
Lower limit of 2T:
Upper limit of 2T:
If the result of Lim_min_2T or Lim_max_2T is not an integer value, it will be rounded up.
If the TX/RX data buffer control logic detects the start bit, the data stream is written in the TX/RX data buffer byte by byte. The
start bit is part of the first data byte and must be different from the bits of the preburst. If the preburst consists of a sequence of
“00000...”, the start bit must be a “1”. If the preburst consists of a sequence of “11111...”, the start bit must be a “0”.
If the data stream consists of more than 16 bytes, a buffer overflow occurs and the TX/RX data buffer control logic overwrites
the bytes already stored in the TX/RX data buffer. Therefore, it is very important to ensure that the data is read in time so that no
buffer overflow occurs (see Figure 8-1 on page 42). There is a counter that indicates the number of received bytes in the TX/RX
data buffer (see section “Transceiver Configuration” on page 42). If a byte is transferred to the microcontroller, the counter is
decremented; if a byte is received, the counter is incremented. The counter value is available via the 4-wire serial interface.
An interrupt is issued if the counter (while counting up) reaches the value defined by the control bits IR0 and IR1 in control
register 1.
SDO_TMDO
Demod_Out
Bit check ok
Preburst Byte 2
Byte 1
Start
bit
'0' '0' '0' '0' '0' '0' '0' '0' '0' '1' '1''0' '0' '0' '0' '0' '0' '1' '1' '1' '1' '0' '0' '1' '1' '0' '1' '0' '1' '1' '0' '0'
Bit-check mode Receiving mode
Byte 3
Lim_min_2T Lim_min Lim_max+()Lim_max Lim_min–()/2–=
TLim_min_2T Lim_min_2T TXDCLK
×=
Lim_max_2T Lim_min Lim_max+()Lim_max Lim_min–()/2+=
TLim_max_2T Lim_max_2T - 1()TXDCLK
×=
53Atmel ATA5428 [DATASHEET]
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Figure 9-9. Receiving Mode (TMODE = 0)
If the TX/RX data buffer control logic detects a bit error, an interrupt is issued and the transceiver is set back to the start-up
mode (see Figure 9-1 on page 47, Figure 9-2 on page 48 and Figure 9-10).
Bit error: a) tee < TLim_min or TLim_max < tee < TLim_min_2T or tee > TLim_max_2T
b) Logical error (no edge detected in the bit center)
Note: The byte consisting of the bit error will not be stored in the TX/RX data buffer. Thus, it is not available via the 4-
wire serial interface.
Writing the control register 1, 4, 5 or 6 during receiving mode resets the TX/RX data buffer control logic and the counter which
indicates the number of received bytes. If the bits OPM0 and OPM1 are still “1” after writing to a control register, the transceiver
changes to the start-up mode (start-up signal processing).
Figure 9-10. Bit Error (TMODE = 0)
Table 9-2. RX Modulation Scheme
Mode ASK/_NFSK T_MODE RFIN
Bit in TX/RX Data
Buffer
Level on Pin
SD0_TMDO
RX
0
0 fFSK_L →fFSK_H 1 X
0 fFSK_H →fFSK_L 0 X
1 fFSK_H – 1
1 fFSK_L – 0
1
0 fASK off →fASK on 1 X
0 fASK on →fASK off 0 X
1 fASK on – 1
1 fASK off – 0
Demod_Out
Bit check ok
Preburst Byte 2
LSB
Readable via 4-wire serial interface
TX/RX Data Buffer
MSB
Byte 1
Start
bit
T2T
'0' '0' '0' '0' '0' '0' '0' '0' '0' '1' '1''0' '0' '0' '0' '0'
Byte 14, Byte 30, ...
Byte 13, Byte 29, ...
Byte 10, Byte 26, ...
Byte 9, Byte 25, ...
Byte 8, Byte 24, ...
Byte 3, Byte 19, ...
Byte 1, Byte 17, ...
Byte 2, Byte 18, ...
Byte 4, Byte 20, ...
Byte 5, Byte 21, ...
Byte 6, Byte 22, ...
Byte 7, Byte 23, ...
Byte 11, Byte 27, ...
Byte 12, Byte 28, ...
Byte 16, Byte 32, ...
Byte 15, Byte 31, ...
11 111001
11 000000
'0' '1' '1' '1' '1' '0' '0' '1' '1' '0' '1' '0' '1' '1' '0' '0'
Bit-check mode Receiving mode
Byte 3
Demod_Out
Bit check ok
Byte n-1 Byte 1
Byte n+1 Preburst
Byte n
Start-up mode Bit-check modeReceiving mode Receiving mode
Bit error
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9.1.8 Recommended Lim_min and Lim_max for Maximum Sensitivity
The sensitivity measurements in the section “Low-IF Receiver” in Table 3-3 on page 11 and Table 3-4 on page 11 have been
done with the Lim_min and Lim_max values according to Table 9-3. These values are optimized for maximum sensitivity. Note
that since these limits are optimized for sensitivity, the number of checked bits, NBit-check, has to be at least 6 to prevent the
circuit from waking up to often in polling mode due to noise.
9.2 TX Operation
The transceiver is set to TX operation by using the bits OPM0 and OPM1 in the control register 1.
Before activating TX mode, the TX parameters (bit rate, modulation scheme, etc.) must be selected as illustrated in Figure 9-11
on page 55. The bit rate depends on Baud 0 and Baud 1 in control register 6, Lim_min0 to Lim_min5 in control register 5 and
XLIM in control register 4 (see section “Control Register” on page 32). The modulation is selected with ASK/_NFSK in control
register 4. The FSK frequency deviation is fixed to about ±16kHz. If P_Mode is set to “1”, the Manchester modulator is disabled
and pattern mode is active (NRZ, see Table 9-5 on page 57).
After the transceiver is set to TX mode, the start-up mode is active and the PLL is enabled. If the PLL is locked, the TX mode is
active.
If the transceiver is in start-up or TX mode, the TX/RX data buffer can be loaded via the 4-wire serial interface. After the first
byte is in the buffer and the TX mode is active, the transceiver starts transmitting automatically (beginning with the MSB). While
transmitting it is always possible to load new data in the TX/RX data buffer. To prevent a buffer overflow or interruptions during
transmitting, the user must ensure that data is loaded at the same speed as it is transmitted.
There is a counter that indicates the number of bytes to be transmitted (see section “Transceiver Configuration” on page 42). If
a byte is loaded, the counter is incremented, if a byte is transmitted, the counter is decremented. The counter value is available
via the 4-wire serial interface. An IRQ is issued if the counter (while counting down) reaches the value defined by the control bits
IR0 and IR1 in control register 1.
Note: Writing to the control register 1, 4, 5 or 6 during TX mode resets the TX/RX data buffer and the counter which indi-
cates the number of bytes to be transmitted.
If T_Mode in control register 1 is set to “1”, the transceiver is in TX transparent mode. In this mode the TX/RX data buffer is
disabled and the TX data stream must be applied on pin SDI_TMDI. Figure 9-11 on page 55 illustrates the flow chart of the TX
transparent mode.
Table 9-3. Recommended Lim_min and Lim_max Values for Different Bit Rates
fRF (fXTAL)/
MHz
1.0 Kbit/s
BR_Range_0
XLim = 1
2.4 Kbit/s
BR_Range_0
XLim = 0
5 Kbit/s
BR_Range_1
XLim = 0
10 Kbit/s
BR_Range_2
XLim = 0
20 Kbit/s
BR_Range_3
XLim = 0
433.92
(13.25311)
Lim_min = 13 (251 µs)
Lim_max = 38 (715 µs)
Lim_min = 12 (116 µs)
Lim_max = 34 (319 µs)
Lim_min = 11 (53 µs)
Lim_max = 32 (150 µs)
Lim_min = 11 (27 µs)
Lim_max = 32 (75 µs)
Lim_min = 11 (13 µs)
Lim_max = 32 (37 µs)
868.3
(13.41191)
Lim_min = 13 (248 µs)
Lim_max = 38 (706 µs)
Lim_min = 12 (115 µs)
Lim_max = 34 (315 µs)
Lim_min = 11 (52 µs)
Lim_max = 32 (148 µs)
Lim_min = 11 (26 µs)
Lim_max = 32 (74 µs)
Lim_min = 11 (13 µs)
Lim_max = 32 (37 µs)
Table 9-4. Control Register 1
OPM1 OPM0 Function
0 1 TX mode
55Atmel ATA5428 [DATASHEET]
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Figure 9-11. TX Operation (T_MODE = 0)
Write TX/RX Data Buffer (max. 16 - number of bytes still
in the TX/RX Data Buffer)
Write TX/RX Data Buffer (max. 16 byte)
Baud1, BAUD0:
Lim_max0 to Lim_max5:
Select baud rate range
Don't care
Write Control Register 6
Lim_min0 to Lim_min5:
Bit_ck0, Bit_ck1:
Select the baud rate
Don't care
Write Control Register 5
Set IDLEOPM1, OPM0:
Write Control Register 1
N
Y
N
Y
Y
NPin IRQ = 1 ?
Idle Mode
TX Mode
Start-up
Mode (TX)
Idle Mode
Command: Delete_IRQ
TX more Data
Bytes ?
FR7, FR8:
VSOUT_EN:
CLK_ON:
Adjust fRF
Set VSOUT_EN = 1
Don't care
Write Control Register 3
FR0 to FR6:
P_mode:
Adjust fRF
Enable or disable the
Manchester modulator
Write Control Register 2
IR1, IR0:
AVCC_EN:
FS:
OPM1, OPM0:
T_mode:
Select an event which activates
an interrupt
Don't care
Select operation frequency
Set OPM1 = 0 and OPM0 = 1
Set T_mode = 0
Write Control Register 1
XLim:
ASK/_NFSK:
Sleep0 to Sleep4:
XSleep:
Select the bit rate
Select modulation
Don't care
Don't care
Write Control Register 4
Pin IRQ = 1 ?
TStartup = 331.5 × TDCL
K
56Atmel ATA5428 [DATASHEET]
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Figure 9-12. TX Transparent Mode (T_MODE = 1)
Apply TX Data on Pin SDI_TMDI
Set IDLE (OPM1 = 0, OPM0 = 1OPM1, OPM0:
Write Control Register 1
Idle Mode
TX Mode
Start-up
Mode (TX)
Idle Mode
FR7, FR8:
VSOUT_EN:
CLK_ON:
Adjust fRF
Set VSOUT_EN = 1
Don't care
Write Control Register 3
FR0 to FR6:
P_mode:
Adjust fRF
Don't care
Write Control Register 2
IR1, IR0:
AVCC_EN:
FS:
OPM1, OPM0:
T_mode:
Don't care
Don't care
Select operation frequency
Set OPM1 = 0 and OPM0 = 1
Set T_mode = 1
Write Control Register 1
XLim:
ASK/_NFSK:
Sleep0 to Sleep4:
XSleep:
Don't care
Select modulation
Don't care
Don't care
Write Control Register 4
TStartup = 331.5 × TDCL
K
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9.3 Interrupts
Via pin IRQ, the transceiver signals different operating conditions to a connected microcontroller. If a specific operating
condition occurs, pin IRQ is set to high.
If an interrupt occurs, it is recommended to delete the interrupt immediately by reading the status register, so that a further
potential interrupt doesn’t get lost. If the Interrupt pin doesn’t switch to low by reading the status register, the interrupt was
triggered by the RX/TX data buffer. In this case read or write the RX/TX data buffer according to Table 9-6.
Table 9-5. TX Modulation Schemes
Mode ASK/_NFSK P_Mode T_Mode
Bit in TX/RX
Data Buffer
Level on Pin
SDI_TMDI RFOUT
TX
0
0 0 1 X fFSK_L →fFSK_H
0 0 0 X fFSK_H →fFSK_L
1 0 1 X fFSK_H
1 0 0 X fFSK_L
X 1 X 1 fFSK_H
X 1 X 0 fFSK_L
1
0 0 1 X fASK off →fASK on
0 0 0 X fASK on →fASK off
1 0 1 X fASK on
1 0 0 X fASK off
X 1 X 1 fASK on
X 1 X 0 fASK off
Table 9-6. Interrupt Handling
Operating Conditions Which Set Pin IRQ to High Level Operations Which Set Pin IRQ to Low Level
Events in Status Register
State transition of status bit STn
(0 →1; 1 →0)
Read status register or
Command Delete IRQ
Appearance of status bit Power_On
(0 →1)
Appearance of status bit P_On_Aux
(0 →1)
Events During TX Operation (T_MODE = 0)
4, 8 or 12 Bytes are in the TX data buffer or the TX data buffer
is empty (depends on IR0 and IR1 in control register 1).
Write TX data buffer or
Write control register 1 or
Write control register 4 or
Write control register 5 or
Write control register 6 or
Command delete IRQ
Events During RX Operation (T_MODE = 0)
4, 8 or 12 received bytes are in the RX data buffer or a
receiving error is occurred (depends on IR0 and IR1 in control
register 1).
Read RX data buffer(1) or
Write control register 1 or
Write control register 4 or
Write control register 5 or
Write control register 6 or
Command delete IRQ
Successful bit check (P_MODE = 0)
Note: 1. During reading of the RX/TX buffer, no IRQ is issued, due to the received bytes or a receiving error.
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10. Absolute Maximum Ratings
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating
only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this
specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Parameters Symbol Min. Max. Unit
Junction temperature Tj150 °C
Storage temperature Tstg –55 +125 °C
Ambient temperature Tamb –40 +85 °C
Supply voltage VS2 VMaxVS2 –0.3 +7.2 V
Supply voltage VS1 VMaxVS1 –0.3 +4 V
Supply voltage VAUX VMaxVAUX –0.3 +7.2 V
Supply voltage VSINT VMaxVSINT –0.3 +5.5 V
ESD (Human Body Model ESD S 5.1)
every pin HBM –1.5 + 1.5 kV
ESD (Machine Model JEDEC A115A)
every pin MM –200 +200 V
ESD (Field Induced Charge Device Model ESD
STM 5.3.1–1999)
every pin
FCDM –1 +1 kV
Maximum input level, input matched to 50 ΩPin_max 10 dBm
11. Thermal Resistance
Parameters Symbol Value Unit
Junction ambient RthJA 25 K/W
59Atmel ATA5428 [DATASHEET]
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12. Electrical Characteristics: General
This device is manufactured with an industrial (not automotive) grade process and process controls. Although this device may meet
certain automotive grade criteria in performance, Atmel can not recommend that this device be used in any automotive application.
All parameters refer to GND and are valid for Tamb = 25°C, VVS1 = VVS2 = 3.0V (1-battery application), VVS2 = 6.0V (2-battery application)
and VVS2 = VVAUX = 5.0V (Base-station Application). Typical values are given at fRF = 433.92 MHz unless otherwise specified. Details
about current consumption, timing and digital pin properties can be found in the specific sections of the “Electrical Characteristics”.
No. Parameters Test Conditions Pin(1) Symbol Min. Typ. Max. Unit Type*
1RtX_TX_IDLE Mode
1.1 RF operating frequency
range
ATA5428
V433_N868 =AVCC 4, 10 fRF 431.5 436.5 MHz A
ATA5428
V433_N868 =GND 4, 10 fRF 862 872 MHz A
1.2 Supply current
OFF mode
VVS1 =V
VS2 =3V,
VVSINT =0V
(1 battery) and
VVS2 = 6V (2 battery)
OFF mode is not
available if
VVS2 =V
VAUX =5V
VVSINT =0V (base
station)
IS_OFF < 10 nA A
1.3 Supply current
IDLE mode
VVSOUT disabled,
XTO running
VVS1 = VVS2 = 3V
(1 battery)
IS_IDLE 220 µA B
VVS2 = 6V (2 battery) IS_IDLE 310 µA B
VVS2 = VVAUX = 5V
(base station) IS_IDLE 310 µA B
1.4 System start-up time
From OFF mode to
IDLE mode including
reset and XTO start-up
(see Figure 7-4 on
page 40)
XTAL: Cm = 5fF,
C0 = 1.8pF, Rm =15Ω
TPWR_ON_IRQ_1 0.3 ms C
1.5 RX start-up time
From IDLE mode to
receiving mode
NBit-check = 3
Bit rate = 20Kbit/s,
BR_Range_3
(see Figure 9-1 on
page 47, Figure 9-2 on
page 48 and Figure 9-3
on page 49)
TStartup_PLL +
TStartup_Sig_Proc
+ TBit-chek
1.39 ms A
1.6 TX start-up time
From IDLE mode to TX
mode (see Figure 9-11
on page 55)
TStartup 0.4 ms A
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note: 1. Pin numbers in brackets mean they were measured with RF_IN matched to 50Ω according to Figure 3-1 on page 11
with component values according to Table 3-2 on page 11 and RF_OUT matched to 50Ω according to Figure 3-10 on page
18 with component values according to Table 3-7 on page 19.
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2Receiver/RX Mode
2.1 Supply current RX
mode
fRF = 433.92MHz 17, 18 IS_RX 10.5 mA A
fRF = 868MHz 17, 18 IS_RX 10.3 mA A
2.2 Supply current
RX polling mode
TSleep = 49.45ms
XSLEEP = 8, Sleep = 5
Bit rate = 20Kbit/s FSK,
VVSOUT disabled
17, 18 IP444 µA B
2.3 Input sensitivity FSK
fRF = 433.92MHz
FSK deviation
fDEV = ±16kHz
limits according to
Table 9-3 on page 54,
BER = 10-3
Tamb = 25°C
Bit rate 20Kbit/s (4) PREF_FSK –104.0 –106.0 –107.5 dBm B
Bit rate 2.4bit/s (4) PREF_FSK –107.5 –109.5 –111.0 dBm B
2.4 Input sensitivity ASK
fRF = 433.92MHz
ASK 100%, level of
carrier limits according
to Table 9-3 on page
54, BER = 10-3
Tamb = 25°C
Bit rate 10Kbit/s (4) PREF_ASK –110.5 –112.5 –114.0 dBm B
Bit rate 2.4Kbit/s (4) PREF_ASK –114.5 –116.5 –118.0 dBm B
2.5
Sensitivity change at
fRF = 868.3MHz
compared to
fRF = 433.92MHz
fRF = 433.92 MHz
to fRF = 868.3 MHz
P = PREF_ASK + ΔPREF1 +
ΔPREF2
P = PREF_FSK + ΔPREF1 +
ΔPREF2
(4) ΔPREF1 +2.7 dB B
2.6 Maximum frequency
offset in FSK mode
Maximum frequency
difference of fRF
between receiver and
transmitter in FSK
mode (fRF is the center
frequency of the FSK
signal with
fDEV = ±16kHz)
(4) ΔfOFFSET –58 +58 kHz B
12. Electrical Characteristics: General (Continued)
This device is manufactured with an industrial (not automotive) grade process and process controls. Although this device may meet
certain automotive grade criteria in performance, Atmel can not recommend that this device be used in any automotive application.
All parameters refer to GND and are valid for Tamb = 25°C, VVS1 = VVS2 = 3.0V (1-battery application), VVS2 = 6.0V (2-battery application)
and VVS2 = VVAUX = 5.0V (Base-station Application). Typical values are given at fRF = 433.92 MHz unless otherwise specified. Details
about current consumption, timing and digital pin properties can be found in the specific sections of the “Electrical Characteristics”.
No. Parameters Test Conditions Pin(1) Symbol Min. Typ. Max. Unit Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note: 1. Pin numbers in brackets mean they were measured with RF_IN matched to 50Ω according to Figure 3-1 on page 11
with component values according to Table 3-2 on page 11 and RF_OUT matched to 50Ω according to Figure 3-10 on page
18 with component values according to Table 3-7 on page 19.
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2.7 Supported FSK
frequency deviation
With up to 2dB
loss of sensitivity.
Note that the tolerable
frequency offset is for
fDEV = ±22kHz, 6kHz
lower than for
fDEV = ±16kHz hence
ΔfOFFSET ≤±52kHz
(4) fDEV ±14 ±16 ±22 kHz B
2.8 System noise figure fRF = 433.92MHz (4) NF 7.0 dB B
fRF = 868.3MHz (4) NF 9.7 dB B
2.9 Intermediate frequency fRF = 433.92MHz fIF 223 kHz A
fRF = 868.3MHz fIF 226 kHz A
2.10 System bandwidth
This value is for
information only!
Note that for crystal and
system frequency offset
calculations, ΔfOFFSET
must be used.
(4) SBW 185 kHz A
2.11
System outband
2nd-order input
intercept point with
respect to fIF
Δfmeas1 = 1,800MHz
Δfmeas2 = 2,026MHz
fIF = Δfmeas2 – Δfmeas1
(4) IIP2 +50 dBm C
2.12
System outband
3rd-order input
intercept point
Δfmeas1 = 1.8MHz
Δfmeas2 = 3.6MHz
fRF = 433.92MHz (4) IIP3 –21 dBm C
fRF = 868.3MHz (4) IIP3 –17 dBm C
2.13 System outband input
1dB compression point
Δfmeas1 = 1MHz
fRF = 433.92MHz (4) I1dBCP –30 dBm C
fRF = 868.3MHz (4) I1dBCP –27 dBm C
2.14 LNA input impedance fRF = 433.92 MHz 4 Zin_LNA (32 – j169) ΩC
fRF = 868.3MHz 4 Zin_LNA (21 – j78) ΩC
2.15
Allowable peak RF
input level, ASK and
FSK
BER < 10-3,
ASK: 100% (4) PIN_max +10 –10 dBm C
FSK: fDEV = ±16kHz (4) PIN_max +10 –10 dBm C
2.16 LO spurious emission
at LNA_IN
f < 1GHz (4) –57 dBm C
f >1GHz (4) –47 dBm C
fRF = 433.92MHz (4) –97 dBm C
fRF = 868.3MHz (4) –84 dBm C
12. Electrical Characteristics: General (Continued)
This device is manufactured with an industrial (not automotive) grade process and process controls. Although this device may meet
certain automotive grade criteria in performance, Atmel can not recommend that this device be used in any automotive application.
All parameters refer to GND and are valid for Tamb = 25°C, VVS1 = VVS2 = 3.0V (1-battery application), VVS2 = 6.0V (2-battery application)
and VVS2 = VVAUX = 5.0V (Base-station Application). Typical values are given at fRF = 433.92 MHz unless otherwise specified. Details
about current consumption, timing and digital pin properties can be found in the specific sections of the “Electrical Characteristics”.
No. Parameters Test Conditions Pin(1) Symbol Min. Typ. Max. Unit Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note: 1. Pin numbers in brackets mean they were measured with RF_IN matched to 50Ω according to Figure 3-1 on page 11
with component values according to Table 3-2 on page 11 and RF_OUT matched to 50Ω according to Figure 3-10 on page
18 with component values according to Table 3-7 on page 19.
62Atmel ATA5428 [DATASHEET]
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2.17 Image rejection Within the complete
image band (4) 20 30 dB A
2.18 Useful signal to
interfering signal ratio
Peak level of useful
signal to peak level of
interferer for
BER < 10-3 with any
modulation scheme of
interferer
FSK BR_Ranges 0, 1,
2(4) SNRFSK0-2 2 3 dB B
FSK BR_Range_3 (4) SNRFSK3 4 6 dB B
ASK (PRF < PRFIN_High)(4) SNRASK 10 12 dB B
2.19 RSSI output
Dynamic range (4), 36 DRSSI 70 dB A
Lower level of range
fRF = 433.92MHz
fRF = 868.3MHz
(4), 36 PRFIN_Low –115
–112
dBm
dBm
A
Upper level of range
fRF = 433.92 MHz
fRF = 868.3 MHz
(4), 36 PRFIN_High –45
–42
dBm
dBm
A
Gain (4), 36 5.5 8.0 10.5 mV/dB A
Output voltage range (4), 36 OVRSSI 400 1100 mV A
2.20 Output resistance RSSI
pin
RX mode
TX mode 36 RRSSI
8
32
10
40
12.5
50 kΩC
12. Electrical Characteristics: General (Continued)
This device is manufactured with an industrial (not automotive) grade process and process controls. Although this device may meet
certain automotive grade criteria in performance, Atmel can not recommend that this device be used in any automotive application.
All parameters refer to GND and are valid for Tamb = 25°C, VVS1 = VVS2 = 3.0V (1-battery application), VVS2 = 6.0V (2-battery application)
and VVS2 = VVAUX = 5.0V (Base-station Application). Typical values are given at fRF = 433.92 MHz unless otherwise specified. Details
about current consumption, timing and digital pin properties can be found in the specific sections of the “Electrical Characteristics”.
No. Parameters Test Conditions Pin(1) Symbol Min. Typ. Max. Unit Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note: 1. Pin numbers in brackets mean they were measured with RF_IN matched to 50Ω according to Figure 3-1 on page 11
with component values according to Table 3-2 on page 11 and RF_OUT matched to 50Ω according to Figure 3-10 on page
18 with component values according to Table 3-7 on page 19.
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2.21 Blocking
Sensitivity (BER = 10–3)
is reduced by 6dB if a
continuous wave
blocking signal at ±Δf is
ΔPBlock higher than the
useful signal level
(bit rate = 20 bit/s,
FSK, fDEV ±16kHz,
Manchester code)
fRF = 433.92MHz
Δf ±0.75MHz
Δf ±1.0MHz
Δf ±1.5MHz
Δf ±5MHz
Δf ±10MHz
(4) ΔPBlock
55
59
62
68
70
dBC C
fRF = 868.3MHz
Δf ±0.75MHz
Δf ±1.0MHz
Δf ±1.5MHz
Δf ±5MHz
Δf ±10MHz
(4) ΔPBlock
50
53
57
67
69
dBC C
2.22 CDEM Capacitor connected to
pin 37 (CDEM) 37 –5% 15 +5% nF D
3Power Amplifier/TX Mode
3.1
Supply current TX
mode power amplifier
OFF
fRF = 868.3MHz IS_TX_PAOFF 6.50 mA A
fRF = 433.92MHz IS_TX_PAOFF 6.95 mA A
3.2 Output power 1
VVS1 = VVS2 = 3V
Tamb = 25°C
VPWR_H = 0V
fRF = 433.92MHz
RR_PWR = 56kΩ
RLopt = 2.3kΩ
fRF = 868.3MHz
RR_PWR = 30kΩ
RLopt = 1.3kΩ
RF_OUT matched to
RLopt //
j/(2 × π × fRF × 1.0pF)
(10) PREF1 –2.5 0+2.5 dBm B
12. Electrical Characteristics: General (Continued)
This device is manufactured with an industrial (not automotive) grade process and process controls. Although this device may meet
certain automotive grade criteria in performance, Atmel can not recommend that this device be used in any automotive application.
All parameters refer to GND and are valid for Tamb = 25°C, VVS1 = VVS2 = 3.0V (1-battery application), VVS2 = 6.0V (2-battery application)
and VVS2 = VVAUX = 5.0V (Base-station Application). Typical values are given at fRF = 433.92 MHz unless otherwise specified. Details
about current consumption, timing and digital pin properties can be found in the specific sections of the “Electrical Characteristics”.
No. Parameters Test Conditions Pin(1) Symbol Min. Typ. Max. Unit Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note: 1. Pin numbers in brackets mean they were measured with RF_IN matched to 50Ω according to Figure 3-1 on page 11
with component values according to Table 3-2 on page 11 and RF_OUT matched to 50Ω according to Figure 3-10 on page
18 with component values according to Table 3-7 on page 19.
64Atmel ATA5428 [DATASHEET]
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3.3
Supply current TX
mode power amplifier
ON 1
PA on/0 dBm
fRF = 433.92 MHz 17, 18 IS_TX_PAON1 8.6 mA B
fRF = 868.3 MHz 17, 18 IS_TX_PAON1 9.6 mA B
3.4 Output power 2
VVS1 = VVS2 = 3V
Tamb = 25°C
VPWR_H = 0V
fRF = 433.92MHz
RR_PWR = 27kΩ
RLopt = 1.1kΩ
fRF = 868.3MHz
RR_PWR = 16kΩ
RLopt = 0.5kΩ
RF_OUT matched to
RLopt//
j/(2 × π × fRF × 1.0pF)
(10) PREF2 3.5 5.0 6.5 dBm B
3.5
Supply current TX
mode power amplifier
ON 2
PA on/5 dBm
fRF = 433.92MHz 17, 18 IS_TX_PAON2 10.5 mA B
fRF = 868.3MHz 17, 18 IS_TX_PAON2 11.2 mA B
3.6 Output power 3
VVS1 = VVS2 = 3V
Tamb = 25°C
VPWR_H = AVCC
fRF = 433.92MHz
RR_PWR = 27kΩ
RLopt = 0.36kΩ
fRF = 868.3MHz
RR_PWR = 20kΩ
RLopt = 0.22kΩ
RF_OUT matched to
RLopt//
j/(2 × π × fRF × 1.0pF)
(10) PREF3 8.5 10 11.5 dBm B
3.7
Supply current TX
mode power amplifier
ON 3
PA on/10dBm
fRF = 433.92MHz 17, 18 IS_TX_PAON3 15.8 mA B
fRF = 868.3MHz 17, 18 IS_TX_PAON3 17.3 mA B
12. Electrical Characteristics: General (Continued)
This device is manufactured with an industrial (not automotive) grade process and process controls. Although this device may meet
certain automotive grade criteria in performance, Atmel can not recommend that this device be used in any automotive application.
All parameters refer to GND and are valid for Tamb = 25°C, VVS1 = VVS2 = 3.0V (1-battery application), VVS2 = 6.0V (2-battery application)
and VVS2 = VVAUX = 5.0V (Base-station Application). Typical values are given at fRF = 433.92 MHz unless otherwise specified. Details
about current consumption, timing and digital pin properties can be found in the specific sections of the “Electrical Characteristics”.
No. Parameters Test Conditions Pin(1) Symbol Min. Typ. Max. Unit Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note: 1. Pin numbers in brackets mean they were measured with RF_IN matched to 50Ω according to Figure 3-1 on page 11
with component values according to Table 3-2 on page 11 and RF_OUT matched to 50Ω according to Figure 3-10 on page
18 with component values according to Table 3-7 on page 19.
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3.8
Output power variation
for full temperature and
supply voltage range
Tamb = –40°C to +85°C
Pout = PREFX + ΔPREFX
X = 1, 2 or 3
VVS1 = VVS2 = 3.0V
(10) ΔPREF –0.8 –1.5 dB B
VVS1 = VVS2 = 2.7V (10) ΔPREF –2.5 dB B
VVS1 = VVS2 = 2.4V (10) ΔPREF –3.5 dB B
3.9 Impedance RF_OUT in
RX mode
fRF = 433.92MHz 10 ZRF_OUT_RX (19 – j366) ΩC
fRF = 868.3MHz 10 ZRF_OUT_RX (2.8 – j141) ΩC
3.10 Noise floor power
amplifier at ±10MHz/at 5dBm
fRF = 433.92MHz (10) LTX10M –126 dBC/Hz C
fRF = 868.3MHz (10) LTX10M –125 dBC/Hz C
3.11 ASK modulation rate
This corresponds to
10Kbit/s Manchester
coding and 20Kbit/s
NRZ coding
fData_ASK 110 kHz C
4XTO
4.1
Pulling XTO due to
XTO, CL1 and CL2
tolerances
Pulling at nominal
temperature and supply
voltage
fXTAL = resonant
frequency of the XTAL
C0 ≥ 1.0pF
Rm ≤120Ω
24, 25
ΔfXTO1
A
Cm ≤7.0fF
Cm ≤14fF
–50
–100 fXTAL
+50
+100 ppm
4.2 Transconductance XTO
at start
At start-up; after
start-up the amplitude
is regulated to VPPXTAL
24, 25 gm, XTO 19 ms B
4.3 XTO start-up time
C0 ≤2.2pF
Cm < 14fF
Rm ≤120Ω24, 25 TPWR_ON_IRQ_1 300 800 µs A
4.4 Maximum C0 of XTAL
Required for stable
operation with internal
load capacitors
24, 25 C0max 3.8 pF D
4.5 Internal capacitors CL1 and CL2 24, 25 CL1, CL2 14.8 18 21.2 pF B
12. Electrical Characteristics: General (Continued)
This device is manufactured with an industrial (not automotive) grade process and process controls. Although this device may meet
certain automotive grade criteria in performance, Atmel can not recommend that this device be used in any automotive application.
All parameters refer to GND and are valid for Tamb = 25°C, VVS1 = VVS2 = 3.0V (1-battery application), VVS2 = 6.0V (2-battery application)
and VVS2 = VVAUX = 5.0V (Base-station Application). Typical values are given at fRF = 433.92 MHz unless otherwise specified. Details
about current consumption, timing and digital pin properties can be found in the specific sections of the “Electrical Characteristics”.
No. Parameters Test Conditions Pin(1) Symbol Min. Typ. Max. Unit Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note: 1. Pin numbers in brackets mean they were measured with RF_IN matched to 50Ω according to Figure 3-1 on page 11
with component values according to Table 3-2 on page 11 and RF_OUT matched to 50Ω according to Figure 3-10 on page
18 with component values according to Table 3-7 on page 19.
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4.6
Pulling of radio
frequency fRF due to
XTO, CL1 and CL2
versus temperature and
supply changes
1.0pF ≤ C0 ≤ 2.2pF
Cm ≤14.0fF
Rm ≤120Ω
PLL adjusted with
FREQ at nominal
temperature and supply
voltage
4, 10 ΔfXTO2 –2+2 ppm C
4.7 Amplitude XTAL after
start-up
Cm = 5fF, C0 = 1.8pF
Rm =15Ω
V(XTAL1, XTAL2)
peak-to-peak value 24, 25 VPPXTAL 700 mVpp C
V(XTAL1)
peak-to-peak value 24, 25 VPPXTAL 350 mVpp C
4.8 Real part of XTO
impedance at start-up
C0 ≤2.2pF, small signal
start impedance, this
value is important for
crystal oscillator startup
24, 25 ReXTO –2,000 –1,500 ΩB
4.9
Maximum series
resistance Rm of XTAL
after start-up
C0 ≤2.2pF
Cm ≤14fFΩ24, 25 Rm_max 15 120 ΩB
4.10 Nominal XTAL load
resonant frequency
fRF = 433.92MHz
fRF = 868.3MHz 24, 25 fXTAL
113.25311
13.41191
MHz
MHz
MHz
D
4.11 External CLK frequency
fRF = 433.92MHz
CLK division ratio = 3
CLK has nominal 50%
duty cycle
30 fCLK 4.418 MHz D
fRF = 868.3MHz
CLK division ratio = 3
CLK has nominal 50%
duty cycle
30 fCLK 4.471 MHz D
4.12 DC voltage after start-
up
VDC(XTAL1, XTAL2)
XTO running
(IDLE mode, RX mode
and TX mode)
24, 25 VDCXTO –150 –30 mV C
12. Electrical Characteristics: General (Continued)
This device is manufactured with an industrial (not automotive) grade process and process controls. Although this device may meet
certain automotive grade criteria in performance, Atmel can not recommend that this device be used in any automotive application.
All parameters refer to GND and are valid for Tamb = 25°C, VVS1 = VVS2 = 3.0V (1-battery application), VVS2 = 6.0V (2-battery application)
and VVS2 = VVAUX = 5.0V (Base-station Application). Typical values are given at fRF = 433.92 MHz unless otherwise specified. Details
about current consumption, timing and digital pin properties can be found in the specific sections of the “Electrical Characteristics”.
No. Parameters Test Conditions Pin(1) Symbol Min. Typ. Max. Unit Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note: 1. Pin numbers in brackets mean they were measured with RF_IN matched to 50Ω according to Figure 3-1 on page 11
with component values according to Table 3-2 on page 11 and RF_OUT matched to 50Ω according to Figure 3-10 on page
18 with component values according to Table 3-7 on page 19.
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5Synthesizer
5.1 Spurious TX mode
At ±fCLK, CLK enabled
fRF = 433.92MHz
fRF = 868.3MHz
SPTX –68
–70
dBC C
At ±fXTO
fRF = 433.92MHz
fRF = 868.3MHz
SPTX –66
–60
dBC C
5.2 Spurious RX mode
At ±fCLK, CLK enabled
fRF = 433.92MHz
fRF = 868.3MHz
SPRX
< –75
< –75 dBC C
At ±fXTO
fRF = 433.92MHz
fRF = 868.3MHz
SPRX –75
–68
dBC C
5.3 In loop phase noise
TX mode
Measured at 20kHz
distance to carrier
fRF = 433.92MHz
fRF = 868.3MHz
LTX20k –80
–75
dBC/Hz A
5.4 Phase noise at 1M
RX mode
fRF = 433.92MHz
fRF = 868.3MHz LRX1M
–120
–113 dBC/Hz C
5.5 Phase noise at 1M
TX mode
fRF = 433.92MHz
fRF = 868.3MHz LTX1M
–111
–107 dBC/Hz C
5.6 Phase noise at 10M
RX mode Noise floor PLL LRX10M –135 dBC/Hz C
5.7 Loop bandwidth PLL
TX mode
Frequency where the
absolute value loop
gain is equal to 1
fLoop_PLL 70 kHz B
5.8 Frequency deviation
TX mode
fRF = 433.92MHz
fRF = 868.3MHz fDEV_TX
±16.17
±16.37 kHz D
5.9 Frequency resolution fRF = 433.92MHz
fRF = 868.3MHz 4, 10 ΔfStep_PLL
808.9
818.6 Hz D
5.10 FSK modulation rate
This correspond to
20Kbit/s Manchester
coding and 40Kbit/s
NRZ coding
fData_FSK 120 kHz B
12. Electrical Characteristics: General (Continued)
This device is manufactured with an industrial (not automotive) grade process and process controls. Although this device may meet
certain automotive grade criteria in performance, Atmel can not recommend that this device be used in any automotive application.
All parameters refer to GND and are valid for Tamb = 25°C, VVS1 = VVS2 = 3.0V (1-battery application), VVS2 = 6.0V (2-battery application)
and VVS2 = VVAUX = 5.0V (Base-station Application). Typical values are given at fRF = 433.92 MHz unless otherwise specified. Details
about current consumption, timing and digital pin properties can be found in the specific sections of the “Electrical Characteristics”.
No. Parameters Test Conditions Pin(1) Symbol Min. Typ. Max. Unit Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note: 1. Pin numbers in brackets mean they were measured with RF_IN matched to 50Ω according to Figure 3-1 on page 11
with component values according to Table 3-2 on page 11 and RF_OUT matched to 50Ω according to Figure 3-10 on page
18 with component values according to Table 3-7 on page 19.
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6RX/TX Switch
6.1 Impedance RX mode
RX mode, pin 38 with
short connection to
GND, fRF = 0Hz (DC)
39 ZSwitch_RX 23000 ΩA
fRF = 433.92MHz
fRF = 868.3MHz 39 ZSwitch_RX
(10.3 – j153)
(8.9 – j73) ΩC
6.2 Impedance TX mode
TX mode, pin 38 with
short connection to
GND, fRF = 0Hz (DC)
39 ZSwitch_TX 5ΩA
fRF = 433.92MHz
fRF = 868.3MHz 39 ZSwitch_RX
(4.5 + j4.3)
(5 + j9) ΩC
7Microcontroller Interface
7.1
Voltage range for
microcontroller
interface
IVSINT < 10µA if CLK is
disabled and all
interface pins are in
stable condition and
unloaded
27, 28,
29, 30,
31, 32,
33, 34,
35
2.4 5.25 V A
7.2 CLK output rise and fall
time
fCLK < 4.5MHz
CL = 10pF
CL = Load capacitance
on pin CLK
2.4V ≤VVSINT ≤5.25V
20% to 80% VVSINT
30
trise
tfall
20
20
30
30
ns
ns B
7.4
Current consumption of
the microcontroller
interface
CLK enabled
VVSOUT enabled
CLK disabled
VVSOUT enabled
VVSOUT disabled
CL = Load capacitance
on pin CLK
(All interface pins,
except pin CLK, are in
stable condition and
unloaded)
27 IVSINT
< 10µA
< 10µA
7.5 Internal equivalent
capacitance
Used for current
calculation 30, 27 CCLK 8pF B
12. Electrical Characteristics: General (Continued)
This device is manufactured with an industrial (not automotive) grade process and process controls. Although this device may meet
certain automotive grade criteria in performance, Atmel can not recommend that this device be used in any automotive application.
All parameters refer to GND and are valid for Tamb = 25°C, VVS1 = VVS2 = 3.0V (1-battery application), VVS2 = 6.0V (2-battery application)
and VVS2 = VVAUX = 5.0V (Base-station Application). Typical values are given at fRF = 433.92 MHz unless otherwise specified. Details
about current consumption, timing and digital pin properties can be found in the specific sections of the “Electrical Characteristics”.
No. Parameters Test Conditions Pin(1) Symbol Min. Typ. Max. Unit Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note: 1. Pin numbers in brackets mean they were measured with RF_IN matched to 50Ω according to Figure 3-1 on page 11
with component values according to Table 3-2 on page 11 and RF_OUT matched to 50Ω according to Figure 3-10 on page
18 with component values according to Table 3-7 on page 19.
IVSINT
CCLK CL
+()VVSINT fXTO
××
3
----------------------------------------------------------------------------=
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8Power Supply General Definitions and AUX Mode
8.1
Current consumption of
an external device
connected to pin
VSOUT
IEXT
IEXT = IVSOUT – IVSINT
IEXT = IVSOUT
8.2 AUX mode
8.3 Power supply output
voltage
AUX mode
VVAUX ≥ 4V
IVSOUT ≤13.5mA
(3.25V regulator mode,
V_REG2, see
Figure 5-1 on page 25)
22 VVSOUT 2.7 3.5 V A
8.4 Current in AUX mode
on pin VAUX
IVSOUT = 0
VVAUX = 6V
VVAUX = 4V to 7V
19 IAUX_VAUX 380 500
500
µA
µA
B
8.5 Supply current
AUX mode
CLK enabled
VVSOUT enabled
CLK disabled
VVSOUT enabled
19, 22,
27 IS_AUX
IS_AUX = IAUX_VAUX + IVSINT + IEXT
IS_AUX = IAUX_VAUX + IEXT
8.6 Supported voltage
range VAUX 19 VVAUX 4 6 7 V
12. Electrical Characteristics: General (Continued)
This device is manufactured with an industrial (not automotive) grade process and process controls. Although this device may meet
certain automotive grade criteria in performance, Atmel can not recommend that this device be used in any automotive application.
All parameters refer to GND and are valid for Tamb = 25°C, VVS1 = VVS2 = 3.0V (1-battery application), VVS2 = 6.0V (2-battery application)
and VVS2 = VVAUX = 5.0V (Base-station Application). Typical values are given at fRF = 433.92 MHz unless otherwise specified. Details
about current consumption, timing and digital pin properties can be found in the specific sections of the “Electrical Characteristics”.
No. Parameters Test Conditions Pin(1) Symbol Min. Typ. Max. Unit Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note: 1. Pin numbers in brackets mean they were measured with RF_IN matched to 50Ω according to Figure 3-1 on page 11
with component values according to Table 3-2 on page 11 and RF_OUT matched to 50Ω according to Figure 3-10 on page
18 with component values according to Table 3-7 on page 19.
VSINT
VSOUT
I
VSOUT
I
EXT
I
VSINT
VSINT
VSOUT
I
VSINT
I
EXT
= I
VSOUT
VAUX
IAUX_VAUX
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13. Electrical Characteristics: 1 Li Battery Application (3V)
All parameters refer to GND and are valid for Tamb = 25°C, VVS1 = VVS2 = 3.0V. Application according to Figure 2-1 on page 7.
fRF = 433.92MHz/868.3MHz unless otherwise specified
No. Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Type*
91 Li Battery Application (3V)
9.1
Supported voltage
range (every mode
except high power TX
mode)
1 Li battery application
(3V)
PWR_H = GND
17, 18 VVS1, VVS2 2.4 3.6 V A
9.2
Supported voltage
range (high power TX
mode)
1 Li battery application
(3V)
PWR_H = AVCC
17, 18 VVS1, VVS2 2.7 3.6 V A
9.3 Power supply output
voltage
1 Li battery application
(3V)
VVS1 =V
VS2 ≥2.6V
VAUX open(1)
IVSOUT ≤13.5mA
(no voltage regulator to
stabilize VVSOUT)
VVS1 = VVS2 ≥ 2.425V
VAUX open(1)
IVSOUT ≤1.5mA
(no voltage regulator to
stabilize VVSOUT)
22 VVSOUT 2.4 VVS1 V B
9.4
Supply voltage for
microcontroller
interface
27 VVSINT 2.4 5.25 V A
9.5 Threshold hysteresis VThres_2 – VThres_1 22 ΔVThres 60 80 100 mV B
9.6
Reset threshold
voltage at pin VSOUT
(N_RESET)
22 VThres_1 2.18 2.3 2.42 V A
9.7
Reset threshold
voltage at pin VSOUT
(Low_Batt)
22 VThres_2 2.26 2.38 2.5 V A
9.8 Supply current
OFF mode
VVS1 = VVS2 ≤3.6V
VVSINT = 0V
17, 18,
22, 27 IS_OFF 2350 nA A
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note: 1. The voltage of VAUX may rise up to 2V. The current IVAUX may not exceed 100µA.
I
IDLE_VS1,2
or
I
RX_VS1,2
or
I
Startup_PLL_VS1,2
or
I
TX_VS1,2
VS1
VS2
71Atmel ATA5428 [DATASHEET]
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9.9 Current in IDLE mode
on pin VS1 and VS2
VVS1 = VVS2 ≤3V
IVSOUT = 0
CLK enabled
VVSOUT enabled
CLK disabled
VVSOUT enabled
VVSOUT disabled
17, 18 IIDLE_VS1, 2
312
260
225
430
370
320
µA
µA
µA
A
B
B
9.10 Supply current
IDLE mode
17, 18,
22, 27 IS_IDLE IS_IDLE = IIDLE_VS1, 2 + IVSINT + IEXT
9.11 Current in RX mode on
pin VS1and VS2
VVS1 = VVS2 ≤3V
IVSOUT = 0 17, 18 IRX_VS1, 2 10.5 14 mA A
9.12 Supply current
RX mode
CLK enabled
VVSOUT enabled
17, 18,
22, 27 IS_RX IS_RX = IRX_VS1, 2 + IVSINT + IEXT
9.13
Current during
TStartup_PLL on pin VS1
and VS2
VVS1 = VVS2 ≤3V
IVSOUT = 0 17, 18 IStartup_PLL_VS1, 2 8.8 11.5 mA C
9.14
Current in
RX polling mode on pin
VS1 and VS2
9.15 Supply current
RX polling mode
CLK enabled
VVSOUT enabled
CLK disabled
VVSOUT enabled
VVSOUT disabled
17, 18,
22, 27 IS_Poll
IS_Poll = IP + IVSINT + IEXT
IS_Poll = IP + IEXT
IS_Poll = IP
9.16 Current in TX mode on
pin VS1 and VS2
VVS1 = VVS2 ≤3V
IVSOUT = 0
Pout = 5dBm/10dBm
433.92MHz/5dBm
433.92MHz/10dBm
868.3MHz/5dBm
868.3MHz/10dBm
17, 18 ITX_VS1_VS2
10.4
15.8
10.5
15.8
11.2
17.3
13.5
20.6
13.5
20.5
14.5
22.5
mA B
9.17 Supply current
TX mode
CLK enabled
VVSOUT enabled
CLK disabled
VVSOUT enabled
17, 18,
22, 27 IS_TX
IS_TX = ITX_VS1, 2 + IVSINT + IEXT
IS_TX = ITX_VS1, 2 + IEXT
13. Electrical Characteristics: 1 Li Battery Application (3V) (Continued)
All parameters refer to GND and are valid for Tamb = 25°C, VVS1 = VVS2 = 3.0V. Application according to Figure 2-1 on page 7.
fRF = 433.92MHz/868.3MHz unless otherwise specified
No. Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note: 1. The voltage of VAUX may rise up to 2V. The current IVAUX may not exceed 100µA.
IP
IIDLE_VS1,2 TSLEEP IStartup_PLL_VS1,2 TStartup_PLL IRX_VS1,2 TStartup_Sig_Proc TBitcheck
+()×+×+×
TSleep TStartup_PLL TStartup_Sig_Proc TBitcheck
++ +
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------=
72Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
14. Electrical Characteristics: 2 Li Battery Application (6V)
All parameters refer to GND and are valid for Tamb = 25°C, VVS2 = 6.0V. Application according to Figure 2-3 on page 9
fRF = 433.92MHz/868.3MHz unless otherwise specified
No. Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Type*
10 2 Li Battery Application (6V)
10.1 Supported voltage
range
2 Li battery
application (6V) 17 VVS2 4.4 6.6 V A
10.2 Power supply output
voltage
2 Li battery
application (6V)
VVS2 ≥ 4.4V
VAUX open(1)
IVSOUT ≤13.5mA
(3.3V regulator mode,
V_REG1, see Figure
5-1 on page 25)
22 VVSOUT 3.0 3.5 V A
10.3
Supply voltage for
microcontroller
interface
27 VVSINT 2.4 5.25 V A
10.4 Threshold hysteresis VThres_2 – VThres_1 22 ΔVThres 60 80 100 mV B
10.5
Reset threshold
voltage at pin VSOUT
(N_RESET)
22 VThres_1 2.18 2.3 2.42 V A
10.6
Reset threshold
voltage at pin VSOUT
(Low_Batt)
22 VThres_2 2.26 2.38 2.5 V A
10.7 Supply current
OFF mode
VVS2 ≤6.6V
VVSINT = 0V
17,
22, 27 IS_OFF 10 350 nA A
10.8 Current in IDLE mode
on pin VS2
VVS2 ≤6V
IVSOUT = 0
CLK enabled
VVSOUT enabled
CLK disabled
VVSOUT enabled
VVSOUT disabled
17 IIDLE_VS2
410
348
309
560
490
430
µA
µA
µA
A
B
B
10.9 Supply current IDLE
mode
17,
22, 27 IS_IDLE IS_IDLE = IIDLE_VS2 + IVSINT + IEXT
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note: 1. The voltage of VAUX may rise up to 2V. The current IVAUX may not exceed 100µA.
VS2
I
IDLE_VS2
or
I
RX_VS2
or
I
Startup_PLL_VS2
or
I
TX_VS2
73Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
10.10 Current in RX mode
on pin VS2 IVSOUT = 0 17 IRX_VS2 10.8 14.5 mA B
10.11 Supply current
RX mode
CLK enabled
VVSOUT enabled
17,
22, 27 IS_RX IS_RX = IRX_VS2 + IVSINT + IEXT
10.12 Current during
TStartup_PLL on pin VS2 IVSOUT = 0 17 IStartup_PLL_VS2 9.1 12 mA C
10.13
Current in
RX polling mode on
pin VS2
10.14 Supply current
RX polling mode
CLK enabled
VVSOUT enabled
CLK disabled
VVSOUT enabled
VVSOUT disabled
17,
22, 27 IS_Poll
IS_Poll = IP + IVSINT + IEXT
IS_Poll = IP + IEXT
IS_Poll = IP
10.15 Current in TX mode
on pin VS2
IVSOUT = 0
Pout = 5dBm/10dBm
433.92MHz/5dBm
433.92MHz/10dBm
868.3MHz/5dBm
868.3MHz/10dBm
17, 19 ITX_VS2
10.9
16.3
11.6
17.8
14.0
21.0
15.0
23.0
mA B
10.16 Supply current
TX mode
CLK enabled
VVSOUT enabled
CLK disabled
VVSOUT enabled
17,
22, 27 IS_TX
IS_TX = ITX_VS2 + IVSINT + IEXT
IS_TX = ITX_VS2 + IEXT
14. Electrical Characteristics: 2 Li Battery Application (6V) (Continued)
All parameters refer to GND and are valid for Tamb = 25°C, VVS2 = 6.0V. Application according to Figure 2-3 on page 9
fRF = 433.92MHz/868.3MHz unless otherwise specified
No. Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note: 1. The voltage of VAUX may rise up to 2V. The current IVAUX may not exceed 100µA.
IP
IIDLE_VS2 TSLEEP IStartup_PLL_VS2 TStartup_PLL IRX_VS2 TStartup_Sig_Proc TBitcheck
+()×+×+×
TSleep TStartup_PLL TStartup_Sig_Proc TBitcheck
++ +
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------=
74Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
15. Electrical Characteristics: Base-station Application (5V)
All parameters refer to GND and are valid for Tamb = 25°C, VVS2 = 5.0V. Application according to Figure 2.2 on page 8
fRF = 433.92MHz/868.3MHz unless otherwise specified.
No. Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Type*
11 Base-station Application (5V)
11.1 Supported voltage
range
Base-station
application (5V)
17, 19,
27 VVS2, VAUX 4.75 5.25 V A
11.2 Power supply output
voltage
Base-station
application (5V)
VVS2 = VVAUX
IVSOUT ≤13.5mA
(3.25V regulator mode,
V_REG2, see Figure 5-
1 on page 25)
22 VVSOUT 3.0 3.5 V A
11.3
Supply voltage for
microcontroller-
interface
27 VVSINT 2.4 5.25 V A
11.4 Threshold hysteresis VThres_2 – VThres_1 22 ΔVThres 60 80 100 mV B
11.5
Reset threshold
voltage at pin VSOUT
(N_RESET)
22 VThres_1 2.18 2.3 2.42 V A
11.6
Reset threshold
voltage at pin VSOUT
(Low_Batt)
22 VThres_2 2.26 2.38 2.5 V A
11.7 Current in IDLE mode
on pin VS2 and VAUX
IVSOUT = 0
CLK enabled
VVSOUT enabled
CLK disabled
VVSOUT enabled
VVSOUT disabled
17, 19 IIDLE_VS2_VAUX
444
380
310
580
500
400
µA B
11.8 Supply current in IDLE
mode
17, 19,
22, 27 IS_IDLE IS_IDLE = IIDLE_VS2_VAUX + IVSINT + IEXT
11.9 Current in RX mode on
pin VS2 and VAUX IVSOUT = 0 17, 19 IRX_VS2_VAUX 10.8 14.5 mA B
11.10 Supply current in RX
mode
CLK enabled VVSOUT
enabled
17, 19,
22, 27 IS_RX IS_RX = IRX_VS2_VAUX + IVSINT + IEXT
11.11
Current during
TStartup_PLL on pin VS2
and VAUX
IVSOUT = 0 17, 19 IStartup_PLL_VS2,VA
UX
9.1 12 mA C
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
VAUX
VS2
I
IDLE_VS2,VAUX
or I
RX_VS2,VAUX
or I
Startup_PLL_VS2,VAUX
or I
TX_VS2,VAUX
75Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
11.12
Current in RX_Polling_Mode on pin VS2 and VAUX
11.13 Supply current in RX
polling mode
CLK enabled
VVSOUT enabled
CLK disabled
VVSOUT enabled
VVSOUT disabled
17, 19,
22, 27 IS_Poll
IS_Poll = IP + IVSINT + IEXT
IS_Poll = IP + IEXT
IS_Poll = IP
11.14 Current in TX mode on
pin VS2 and VAUX
IVSOUT = 0
Pout = 5dBm/10dBm
433.92MHz/5dBm
433.92MHz/10dBm
868.3MHz/10dBm
868.3MHz/10dBm
17, 19 ITX_VS2_VAUX
10.9
16.3
11.6
17.8
14.0
21.0
15.0
23.0
mA B
11.15 Supply current in
TX mode
CLK enabled
VVSOUT enabled
CLK disabled
VVSOUT enabled
17, 19,
22, 27 IS_TX
IS_TX = ITX_VS2_VAUX + IVSINT + IEXT
IS_TX = ITX_VS2_VAUX + IEXT
15. Electrical Characteristics: Base-station Application (5V) (Continued)
All parameters refer to GND and are valid for Tamb = 25°C, VVS2 = 5.0V. Application according to Figure 2.2 on page 8
fRF = 433.92MHz/868.3MHz unless otherwise specified.
No. Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
IP
IIDLE_VS2,VAUX TSLEEP IStartup_PLL_VS2,VAUX TStartup_PLL IRX_VS2,VAUX TStartup_Sig_Proc TBitcheck
+()×+×+×
TSleep TStartup_PLL TStartup_Sig_Proc TBitcheck
++ +
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------=
76Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
16. Digital Timing Characteristics
All parameters refer to GND and are valid for Tamb =25°C. V
VS1 =V
S2 = 3.0V (1 Li battery application (3V)), VVS2 = 6.0V (2 Li battery
application (6V)) and VVS2 =5.0V (Base-station Application(5V)) unless otherwise specified.
No. Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Type*
12 Basic Clock Cycle of the Digital Circuitry
12.1 Basic clock cycle TDCLK 16/fXTO 16/fXTO µs A
12.2 Extended basic clock
cycle
XLIM = 0
BR_Range_0
BR_Range_1
BR_Range_2
BR_Range_3
XLIM = 1
BR_Range_0
BR_Range_1
BR_Range_2
BR_Range_3
TXDCLK
8
4
2
1
× TDCLK
16
8
4
2
× TDCLK
8
4
2
1
× TDCLK
16
8
4
2
× TDCLK
µs A
13 RX Mode/RX Polling Mode
13.1 Sleep time
Sleep and XSleep are
defined in control
register 4
TSleep
Sleep ×
XSleep ×
1024 ×
TDCLK
Sleep ×
XSleep ×
1024 ×
TDCLK
ms A
13.2 Start-up PLL RX mode from IDLE mode TStartup_PLL
798.5 ×
TDCLK
798.5 ×
TDCLK
µs A
13.3 Start-up signal
processing
BR_Range_0
BR_Range_1
BR_Range_2
BR_Range_3
TStartup_Sig_Pro
c
882
498
306
210
× TDCLK
882
498
306
210
× TDCLK
A
13.4 Time for bit check
Average time during
polling. No RF signal
applied.
fSignal = 1/(2 × tee)
Signal data rate
Manchester
(Lim_min and Lim_max
up to ±50% of tee, see
Figure 9-4 on page 49)
Bit-check time for a
valid input signal fSignal
NBit-check = 0
NBit-check = 3
NBit-check = 6
NBit-check = 9
TBit_check
3/fSignal
6/fSignal
9/fSignal
1/fSignal
3.5/fSignal
6.5/fSignal
9.5/fSignal
ms C
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
77Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
13.5 Bit-rate range
BR_Range =
BR_Range0
BR_Range1
BR_Range2
BR_Range3
BR_Range
1.0
2.0
4.0
8.0
2.5
5.0
10.0
20.0
Kbit/s A
13.6
Minimum time period
between edges at pin
SDO_TMDO in RX
transparent mode
XLIM = 0
BR_Range_0
BR_Range_1
BR_Range_2
BR_Range_3
XLIM = 1
BR_Range_0
BR_Range_1
BR_Range_2
BR_Range_3
31 TDATA_min
10 ×
TXDCLK
µs A
13.7
Edge-to-edge time
period of the data
signal for full sensitivity
in RX mode
BR_Range_0
BR_Range_1
BR_Range_2
BR_Range_3
TDATA
200
100
50
25
500
250
125
62.5
µs B
14 TX Mode
14.1 Start-up time From IDLE mode TStartup
331.5
× TDCLK
331.5
× TDCLK
µs A
15 Configuration of the Transceiver with 4-wire Serial Interface
15.1 CS set-up time to rising
edge of SCK 33, 35 TCS_setup
1.5 ×
TDCLK
µs A
15.2 SCK cycle time 33 TCycle 2µs A
15.3 SDI_TMDI set-up time
to rising edge of SCK 32, 33 TSetup 250 ns C
15.4
SDI_TMDI hold time
from rising edge of
SCK
32, 33 THold 250 ns C
15.5
SDO_TMDO enable
time from rising edge of
CS
31, 35 TOut_enable 250 ns C
15.6
SDO_TMDO output
delay from falling edge
of SCK
CL = 10 pF 31, 35 TOut_delay 250 ns C
15.7
SDO_TMDO disable
time from falling edge
of CS
31, 33 TOut_disable 250 ns C
15.8 CS disable time period 35 TCS_disable
1.5 ×
TDCLK
µs A
16. Digital Timing Characteristics (Continued)
All parameters refer to GND and are valid for Tamb =25°C. V
VS1 =V
S2 = 3.0V (1 Li battery application (3V)), VVS2 = 6.0V (2 Li battery
application (6V)) and VVS2 =5.0V (Base-station Application(5V)) unless otherwise specified.
No. Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
78Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
15.9 Time period SCK low to
CS high 33, 35 TSCK_setup1 250 ns C
15.10 Time period SCK low to
CS low 33, 35 TSCK_setup2 250 ns C
15.11 Time period CS low to
SCK high 33, 35 TSCK_hold 250 ns C
16 Start Time Push Button Tn and PWR_ON
Timing of Wake-up via PWR_ON or Tn
16.1
PWR_ON high to
positive edge on pin
IRQ (see Figure 7-4 on
page 40)
From OFF mode to
IDLE mode,
applications according
to Figure 2-1 on page 7,
Figure 2.2 on page 8
and
Figure 2-3 on page 9
XTAL:
Cm < 14fF (typ. 5fF)
C0 < 2.2pF (typ. 1.8pF)
Rm ≤ 120Ω (typ. 15Ω)
1 Li battery application
(3V)
C1 = C2 = 68nF
C3 = C4 = 68nF
C5 = 10nF
2 Li battery application
(6V)
C1 = C4 = 68nF
C2 = C3 = 2.2µF
C5 = 10nF
Base-station Application
(5V)
C1 = C3 = C4 = 68nF
C2 = C12 = 2.2µF
C5 = 10nF
29, 40 TPWR_ON_IRQ_
1
0.3
0.45
0.45
0.8
1.3
1.3
ms
ms
ms
B
16. Digital Timing Characteristics (Continued)
All parameters refer to GND and are valid for Tamb =25°C. V
VS1 =V
S2 = 3.0V (1 Li battery application (3V)), VVS2 = 6.0V (2 Li battery
application (6V)) and VVS2 =5.0V (Base-station Application(5V)) unless otherwise specified.
No. Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
79Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
16.2
PWR_ON high to
positive edge on pin
IRQ (see Figure 7-4 on
page 40)
Every mode except
OFF mode 29, 40 TPWR_ON_IRQ_
2
2 ×
TDCLK
µs A
16.3
Tn low to positive edge
on pin IRQ (see Figure
7-2 on page 38)
From OFF mode to
IDLE mode,
applications according
to Figure 2-1 on page 7,
Figure 2.2 on page 8
and Figure 2-3 on page
9
XTAL:
Cm < 14 fF (typ 5 fF)
C0 < 2.2 pF (typ 1.8 pF)
Rm ≤120Ω (typ 15Ω)
1 Li battery application
(3V)
C1 = C2 = 68 nF
C3 = C4 = 68 nF
C5 = 10 nF
2 Li battery application
(6V)
C1 = C4 = 68 nF
C2 = C3 = 2.2 µF
C5 = 10 nF
Base-station Application
(5V)
C1 = C3 = C4 = 68 nF
C2 = C12 = 2.2 µF
C5 = 10 nF
29, 41,
42, 43,
44, 45
TTn_IRQ
0.3
0.45
0.45
0.8
1.3
1.3
ms
ms
ms
B
16.4 Push button debounce
time
Every mode except
OFF mode
29, 41,
42, 43,
44, 45
TDebounce
8195
× TDCLK
8195
× TDCLK
µs A
16. Digital Timing Characteristics (Continued)
All parameters refer to GND and are valid for Tamb =25°C. V
VS1 =V
S2 = 3.0V (1 Li battery application (3V)), VVS2 = 6.0V (2 Li battery
application (6V)) and VVS2 =5.0V (Base-station Application(5V)) unless otherwise specified.
No. Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
80Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
17. Digital Port Characteristics
All parameters refer to GND and are valid for Tamb = –40°C to +85 °C, VVS1 = VS2 = 2.4V to 3.6V (1 Li battery application (3V)) and
VVS2 = 4.4V to 6.6V (2 Li battery application (6V)) and VVS2 = 4.75V to 5.25V (Base-station Application (5V)). Typical values at
VVS1 =V
VS2 = 3V and Tamb = 25°C unless otherwise specified.
No. Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Type*
17 Digital Ports
17.1
CS input
Low level input voltage VVSINT = 2.4V to 5.25V 35 VIl
0.2 ×
VVSINT
V A
High level input voltage VVSINT = 2.4V to 5.25V 35 VIh
0.8 ×
VVSINT
VVSINT V A
17.2
SCK input
Low level input voltage VVSINT = 2.4V to 5.25V 33 VIl
0.2 ×
VVSINT
V A
High level input voltage VVSINT = 2.4V to 5.25V 33 VIh
0.8 ×
VVSINT
VVSINT V A
17.3
SDI_TMDI input
Low level input voltage VVSINT = 2.4V to 5.25V 32 VIl
0.2 ×
VVSINT
V A
High level input voltage VVSINT = 2.4V to 5.25V 32 VIh
0.8 ×
VVSINT
VVSINT V A
17.4 TEST1 input
TEST1 input must
always be directly
connected to GND
20 0 0 V
17.5 TEST2 input
TEST2 input must
always be direct
connected to GND
23 0 0 V
17.6
PWR_ON input
Low level input voltage
Internal pull-down with
series connection of
40kΩ ±20% resistor
and diode
40 VIl 0.4 V A
High level input
voltage(1)
Internal pull-down with
series connection of
40kΩ ±20% resistor
and diode
40 VIh
0.8
× VVS2
V A
17.7
Tn input
Low level input voltage
Internal pull-up resistor
of 50kΩ ±20%
41, 42,
43, 44,
45
VIl
0.2
× VVS2
V A
High level input
voltage(1)
Internal pull-up resistor
of 50kΩ ±20%
41, 42,
43, 44,
45
VIh
× VVS2 –
0.5V V A
17.8
433_N868 input
Low level input voltage 6 VIl 0.25 V A
Input current low 6 IIl –5µA A
High level input voltage 6 VIh 1.7 AVCC V A
Input current high 6 IIh 1µA A
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note: 1. If a logic high level is applied to this pin, a minimum serial impedance of 100Ω must be ensured for proper operation over
full temperature range.
81Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
17.9
PWR_H input
Low level input voltage 9 VIl 0.25 V A
Input current low 9 IIl –5µA A
High level input voltage 9 VIh 1.7 AVCC V A
Input current high 9 IIh 1µA A
17.10
SDO_TMDO output
Saturation voltage low
VVSINT = 2.4V to 5.25V
ISDO_TMDO = 250µA 31 Vol 0.15 0.4 V B
Saturation voltage high VVSINT = 2.4V to 5.25V
ISDO_TMDO = –250µA 31 Voh
VVSINT –
0.4
VVSINT –
0.15 V B
17.11
IRQ output
Saturation voltage low
VVSINT = 2.4V to 5.25V
IIRQ = 250µA 29 Vol 0.15 0.4 V B
Saturation voltage high VVSINT = 2.4V to 5.25V
IIRQ = –250µA 29 Voh
VVSINT –
0.4
VVSINT –
0.15 V B
17.12
CLK output
Saturation voltage low
VVSINT = 2.4V to 5.25V
ICLK = 100µA
internal series resistor
of 1kΩ for spurious
emission reduction in
PLL
30 Vol 0.15 0.4 V B
Saturation voltage high
VVSINT = 2.4V to 5.25V
ICLK = –100µA
internal series resistor
of 1kΩ for spurious
emission reduction in
PLL
30 Voh
VVSINT –
0.4
VVSINT –
0.15 V B
17.13
N_RESET output
Saturation voltage low
VVSINT = 2.4V to 5.25V
IN_RESET = 250µA 28 Vol 0.15 0.4 V B
Saturation voltage high VVSINT = 2.4V to 5.25V
IN_RESET = –250µA 28 Voh
VVSINT –
0.4
VVSINT –
0.15 V B
17.14
RX_ACTIVE output
Saturation voltage low
VVSINT = 2.4V to 5.25V
IRX_ACTIVE = 25µA 46 Vol 0.25 0.4 V B
Saturation voltage high VVSINT = 2.4V to 5.25V
IRX_ACTIVE = –1500µA 46 Voh
VAVCC –
0.5
VAVCC –
0.15 V B
17.15 DEM_OUT output
Saturation voltage low
Open drain output
IDEM_OUT = 250µA 34 Vol 0.15 0.4 V B
17. Digital Port Characteristics (Continued)
All parameters refer to GND and are valid for Tamb = –40°C to +85 °C, VVS1 = VS2 = 2.4V to 3.6V (1 Li battery application (3V)) and
VVS2 = 4.4V to 6.6V (2 Li battery application (6V)) and VVS2 = 4.75V to 5.25V (Base-station Application (5V)). Typical values at
VVS1 =V
VS2 = 3V and Tamb = 25°C unless otherwise specified.
No. Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Type*
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note: 1. If a logic high level is applied to this pin, a minimum serial impedance of 100Ω must be ensured for proper operation over
full temperature range.
82Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
19. Package Information
18. Ordering Information
Extended Type Number Package Remarks Delivery
ATA5428-PLQW QFN48 7 mm × 7 mm Taped and reeled + Dry pack
ATA5428-PLSW QFN48 7 mm × 7 mm Tubes + Dry pack
Note: W = RoHS compliant
0.4±0.1
7
5.5
5.1
0.5 nom.
48
12
1
4837
1324
25
36
12
1
specifications
according to DIN
technical drawings
Issue: 1; 14.01.03
Drawing-No.: 6.543-5089.02-4
Package: QFN 48 - 7 x 7
Exposed pad 5.1 x 5.1
Dimensions in mm
Not indicated tolerances ± 0.05
0.23
0.05-0.05
1 max.
+0
83Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
20. Revision History
Please note that the following page numbers referred to in this section refer to the specific revision mentioned, not to this
document.
Revision No. History
4841E-WIRE-03/12 • Put datasheet in a new template
• Deleted all the cancelled Parts (ATA5423, ATA5425, ATA5429)
4841D-WIRE-10/07 • Put datasheet in a new template
4841C-WIRE-05/06
• Put datasheet in a new template
• kBaud replaced through Kbit/s
• Baud replaced through bit
• Table 9-6 “Interrupt Handling” on page 65 changed
84Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
21. Table of Contents
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
0.1 Typical Remote Control Unit Application with 1 Li Battery (3V) . . . . . . . . . . .7
0.2 Low-IF Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
0.3 Input Matching at RF_IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
0.4 Frequency Accuracy of the Crystals . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
0.5 RX Supply Current versus Temperature and Supply Voltage . . . . . . . . . . .12
0.6 Blocking, Selectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
0.7 In-band Disturbers, Data Filter, Quasi-peak Detector, Data Slicer . . . . . . . .14
0.8 DEM_OUT Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
0.9 RSSI Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
0.10 Frequency Synthesizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
0.11 Output Power and TX Supply Current versus Supply Voltage
and Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
0.12 RX/TX Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
0.13 Matching Network in TX Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
1. XTO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
1.1 Pin CLK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
1.2 Basic Clock Cycle of the Digital Circuitry . . . . . . . . . . . . . . . . . . . . . . . . .24
1.3 OFF Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
1.4 IDLE Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
1.5 Reset Timing and Reset Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
1.6 2 Li Battery Application (6V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
2. Digital Control Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
2.1 Register Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
2.2 Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
2.3 Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
2.4 Pin Tn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
2.5 Pin VAUX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
3. Transceiver Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
3.1 Command: Read TX/RX Data Buffer . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
3.2 Command: Read Control/Status Register . . . . . . . . . . . . . . . . . . . . . . . . .43
3.3 Command: Write Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
3.4 Command: OFF Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
3.5 Command: Delete IRQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
3.6 Command Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
3.7 4-wire Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
4. Operation Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
4.1 RX Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
4.2 TX Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
4.3 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
5. Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58
6. Thermal Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58
7. Electrical Characteristics: General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
8. Electrical Characteristics: 1 Li Battery Application (3V) . . . . . . . . . . . . . . . .70
85Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
9. Electrical Characteristics: 2 Li Battery Application (6V) . . . . . . . . . . . . . . . .72
10. Electrical Characteristics: Base-station Application (5V) . . . . . . . . . . . . . . .74
11. Digital Timing Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76
12. Digital Port Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80
13. Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82
14. Package Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82
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