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Optimum Technology Matching® Applied
GaAs HBT
InGaP HBT
GaAs MESFET
SiGe BiCMOS
Si BiCMOS
SiGe HBT
GaAs pHEMT
Si CMOS
Si BJT
GaN HEMT
Functional Block Diagram
RF MICRO DEVICES®, RFMD®, Optimum Technology Matching®, Enabling Wireless Connectivity™, PowerStar®, POLARIS™ TOTAL RADIO™ and UltimateBlue™ are trademarks of RFMD, LLC. BLUETOOTH is a trade-
mark owned by Bluetooth SIG, Inc., U.S.A. and licensed for use by RFMD. All other trade names, trademarks and registered trademarks are the property of their respective owners. ©2006, RF Micro Devices, Inc.
Product Description
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
RF MEMS
LO
divider
LO
divider
Frac-N
sequence
generator
N divider
Phase /
freq
detector
Charge
pump
Ref
divider
VCO
Synth
Mixers
Mux
RF2051
HIGH PERFORMANCE WIDEBAND RF PLL/VCO WITH
INTEGRATED RF MIXERS
The RF2051 is a low power, high performance, wideband RF frequency conversion
chip with integrated local oscillator (LO) generation and a pair of RF mixers. The RF
synthesizer includes an integrated fractional-N phase locked loop with voltage con-
trolled oscillators (VCOs) and dividers to produce a low-phase noise LO signal with a
very fine frequency resolution. The buffered LO output drives the built-in RF mixers
which convert the signal into the required frequency band. The mixer bias current
can be programmed dependent on the required performance and available supply
current. The LO generation blocks have been designed to continuously cover the
frequency range from 300MHz to 2400MHz. The RF mixers are very broad band
and operate from 30MHz to 2500MHz at the input and output, enabling both up
and down conversion. An external crystal of between 10MHz and 52MHz or an
external reference source of between 10MHz and 104 MHz can be used with the
RF2051 to accommodate a variety of reference frequency options.
All on-chip registers are controlled through a simple three-wire serial interface. The
RF2051 is designed for 2.7V to 3.6V operation for compatibility with portable, bat-
tery powered devices. It is available in a plastic 32-pin, 5mmx5mm QFN package.
Features
30MHz to 2.5GHz Frequency
Range
Fractional-N Synthesizer
Very Fine Frequency Resolution
1.5Hz for 26MHz Reference
Low Phase Noise VCO
On-Chip Crystal-Sustaining
Circuit With Programmable
Loading Capacitors
Two High-Linearity RF Mixers
Integrated LO Buffers
Mixer Input IP3 +18dBm
Mixer Bias Adjustable for Low
Power Operation
Full Duplex Mode
2.7V to 3.6V Power Supply
Low Current Consumption
55mA to 75mA at 3V
3-Wire Serial Interface
Applications
CATV Head-Ends
Digital TV Up/Down Converters
Digital TV Repeaters
Multi-Dwelling Units
Cellular Repeaters
Frequency Band Shifters
UHF/VHF Radios
Diversity Receivers
Software Defined Radios
Satellite Communications
Super-Heterodyne Radios
DS120308
Package: QFN, 32-Pin, 5mmx5mm
RF2051High
Performa nce
Wideband RF
PLL/VCO w ith
Integrated RF
Mixers
2 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Detailed Functional Block Diagram
Pin Out
Serial Data Interface,
Control and Biasing
Analog
Regulator
Digital
Regulator
Mux
LO Divider 1
/1, /2, or /4
LO Divider 2
/1, /2, or /4
LO Buffer 1
LO Buffer 2
Mixer 1
Mixer 2
VCO 1
VCO 2
VCO 3 Voltage Controlled Oscillators
Reference Divider
/1 to /7
Reference Oscillator
Circuitry and
Crystal Tuning
-+
Vref
N Divider
Phase /
Freq
Detector
Frac-N
Sequence
Generator
Charge
Pump
Synthesizer
Vtune
ANA_VDD DIG_VDD
ANA_DEC
LFILT1
LFILT2
LFILT3
INDN
INDP
REXT
XTALIPP
XTALIPN
ENX
ENBL
MODE
RESETB
SDATA
SCLK
RFOP1N
RFOP1P
RFIP1N
RFIP1P
RFIP2P
RFIP2N
RFOP2P
RFOP2N
SERIAL
BUS
CONTROL
ANA_VDD
OP1
4:1
ANA_VDD
OP2
4:1
1:1
IP2
1:1
IP1
1
3
2
6
5
4
7
ENBL
INDP
INDN
REXT
ANA_DEC
LFILT1
LFILT2
8LFILT3
2527 2630 29 2831
NC
NC
RFOP2N
RFOP2P
RESETB
ENX
SCLK
32
SDATA
24
22
23
19
20
21
18
RFIP2P
RFIP2N
ANA_VDD
NC
NC
DIG_VDD
RFOP1P
17 RFOP1N
91110 141312 15
MODE
XTALIPP
XTALIPN
GND
RFIP1P
RFIP1N
NC
16
NC
EP
3 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Note 1: The signal should be connected to this pin such that DC current cannot flow into or out of the chip, either by using AC
coupling capacitors or by use of a transformer (see evaluation board schematic).
Note 2: DC current needs to flow from ANA_VDD into this pin, either through an RF inductor, or transformer (see evaluation
board schematic).
Note 3: Alternatively an external reference can be AC-coupled to pin 11 XTALIPN, and pin 10 XTALIPP decoupled to ground. This
may make PCB routing simpler.
Pin Function Description
1ENBL
Ensure that the ENBL high voltage level is not greater than VDD. An RC low-pass filter could be used to reduce
digital noise.
2INDP
VCO 3 differential inductor. Normally a micro-strip inductor is used to set the VCO 3 frequency range 1200MHz
to 1600MHz.
3INDN
VCO 3 differential inductor. Normally a micro-strip inductor is used to set the VCO 3 frequency range 1200MHz
to 1600MHz.
4REXT
External bandgap bias resistor. Connect a 51k resistor from this pin to ground to set the bandgap reference
bias current. This could be a sensitive low frequency noise injection point.
5ANA_DEC
Analog supply decoupling capacitor. Connect to analog supply and decouple as close to the pin as possible.
6LFILT1
Phase detector output. Low-frequency noise-sensitive node.
7LFILT2
Loop filter op-amp output. Low-frequency noise-sensitive node.
8LFILT3
VCO control input. Low-frequency noise-sensitive node.
9MODE
Mode select pin. An RC low-pass filter can be used to reduce digital noise.
10 XTALIPP Reference crystal / reference oscillator input. Should be AC-coupled if an external reference is used. See note 3.
11 XTALIPN Reference crystal / reference oscillator input. Should be AC-coupled to ground if an external reference is used.
See note 3.
12 GND Connect to ground.
13 RFIP1P Differential input 1. See note 1.
14 RFIP1N Differential input 1. See note 1.
15 NC
16 NC
17 RFOP1N Differential output 1. See note 2.
18 RFOP1P Differential output 1. See note 2.
19 DIG_VDD Digital supply. Should be decoupled as close to the pin as possible.
20 NC
21 NC
22 ANA_VDD Analog supply. Should be decoupled as close to the pin as possible.
23 RFIP2N Differential input 2. See note 1.
24 RFIP2P Differential input 2. See note 1.
25 NC
26 NC
27 RFOP2N Differential output 2. See note 2.
28 RFOP2P Differential output 2. See note 2.
29 RESETB Chip reset (active low). Connect to DIG_VDD if external reset is not required.
30 ENX Serial interface select (active low). An RC low-pass filter could be used to reduce digital noise.
31 SCLK Serial interface clock. An RC low-pass filter could be used to reduce digital noise.
32 SDATA Serial interface data. An RC low-pass filter could be used to reduce digital noise.
EP Exposed pad Connect to ground. This is the ground reference for the circuit. All decoupling should be connected here through
low impedance paths.
4 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Absolute Maximum Ratings
Parameter Rating Unit
Supply Voltage (VDD) -0.5 to +3.6 V
Input Voltage (VIN), any Pin -0.3 to VDD+0.3 V
RF/IF Mixer Input Power +15 dBm
Operating Temperature Range -40 to +85 °C
Storage Temperature Range -65 to +150 °C
Parameter Specification Unit Condition
Min. Typ. Max.
ESD Requirements
Human Body Model
General 2000 V
RF Pins 1000 V
Machine Model
General 200 V
RF Pins 100 V
Operating Conditions
Supply Voltage (VDD) 2.7 3.0 3.6 V
Temperature (TOP) -40 +85 °C
Logic Inputs/Outputs VDD=Supply to DIG_VDD pin
Input Low Voltage -0.3 +0.5 V
Input High Voltage 1.5 VDD V
Input Low Current -10 +10 uA Input=0V
Input High Current -10 +10 uA Input=VDD
Output Low Voltage 0 0.2*VDD V
Output High Voltage 0.8*VDD VDD V
Load Resistance 10 k
Load Capacitance 20 pF
Static
Programmable Supply Current
(IDD)
Low Current Setting 55 mA Only one mixer operating.
High Linearity Setting 75 mA Only one mixer operating.
Standby 3 mA Reference oscillator and bandgap only.
Power Down Current 140 AENBL=0 and REF_STBY=0
Mixer 1/2 Mixer output driving 4:1 balun.
Gain -2 dB Not including balun losses.
Noise Figure
Low Current Setting 9.5 dB
High Linearity Setting 12 dB
Caution! ESD sensitive device.
Exceeding any one or a combination of the Absolute Maximum Rating conditions may
cause permanent damage to the device. Extended application of Absolute Maximum
Rating conditions to the device may reduce device reliability. Specified typical perfor-
mance or functional operation of the device under Absolute Maximum Rating condi-
tions is not implied.
RoHS status based on EUDirective2002/95/EC (at time of this document revision).
The information in this publication is believed to be accurate and reliable. However, no
responsibility is assumed by RF Micro Devices, Inc. ("RFMD") for its use, nor for any
infringement of patents, or other rights of third parties, resulting from its use. No
license is granted by implication or otherwise under any patent or patent rights of
RFMD. RFMD reserves the right to change component circuitry, recommended appli-
cation circuitry and specifications at any time without prior notice.
5 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Parameter Specification Unit Condition
Min. Typ. Max.
Mixer 1/2, cont.
IIP3
Low Current Setting +10 dBm
High Linearity Setting +18 dBm
Pin1dB
Low Current Setting +2 dBm
High Linearity Setting +12 dBm
RF and IF Port Frequency Range 30 2500 MHz
Mixer Input Return Loss 10 dB 100 differential
Voltage Controlled Oscillator
Open Loop Phase Noise at 1MHz
Offset
2GHz LO Frequency -130 dBc/Hz
1GHz LO Frequency -135 dBc/Hz
500MHz LO Frequency -140 dBc/Hz
Reference Oscillator
Xtal Frequency 10 52 MHz
External Reference Frequency 10 104 MHz
Reference Divider Ratio 1 7
External Reference Input Level 500 800 1500 mVP-P AC-coupled
Local Oscillator
Synthesizer Output Frequency 300 2400 MHz Dependant on VCO 3 external inductor. After
LO dividers.
Phase Detector Frequency 52 MHz
Closed Loop Phase-Noise at
10 kHz Offset
26MHz phase detector frequency
2GHz LO Frequency -90 dBc/Hz
1GHz LO Frequency -95 dBc/Hz
500MHz LO Frequency -102 dBc/Hz
6 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Typical Performance Characteristics: Synthesizer and VCO - VDD=3V, T
A=25°C, as measured on RF2051 evaluation board,
for application schematic see page 36. Phase Detector Frequency=26MHz, Loop Bandwidth=60 kHz.
VCO3 With Passive Loop Filter
-160
-140
-120
-100
-80
-60
1 10 100 1000 10000
Offset Frequency (kHz)
Phase Noise (dBc/Hz)
1200MHz
600MHz
300MHz
VCO2 With Passive Loop Filter
-160
-140
-120
-100
-80
-60
1 10 100 1000 10000
Offset Frequency (kHz)
Phase Noise (dBc/Hz)
1600MHz
800MHz
400MHz
VCO1 With Passive Loop Filter
-160
-140
-120
-100
-80
-60
1 10 100 1000 10000
Offset Frequency (kHz)
Phase Noise (dBc/Hz)
2000MHz
1000MHz
500MHz
VCO2 With Active Loop Filter
-160
-140
-120
-100
-80
-60
1 10 100 1000 10000
Offset Frequency (kHz)
Phase Noise (dBc/Hz)
1600MHz
800MHz
400MHz
VCO3 With Active Loop Filter
-160
-140
-120
-100
-80
-60
1 10 100 1000 10000
Offset Frequency (kHz)
Phase Noise (dBc/Hz)
1200MHz
600MHz
300MHz
VCO1 With Active Loop Filter
-160
-140
-120
-100
-80
-60
1 10 100 1000 10000
Offset Frequency (kHz)
Phase Noise (dBc/Hz)
2000MHz
1000MHz
500MHz
7 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Typical Performance Characteristics: Synthesizer and VCO - VDD=3V, T
A=25°C unless stated, as measured on RF2051
evaluation board, for application schematic see page 36.
VCO2 Open Loop Phase Noise
-160
-140
-120
-100
-80
-60
-40
-20
1 10 100 1000 10000
Offset Frequency (kHz)
Phase Noise (dBc/Hz)
2000MHz
1800MHz
1600MHz
VCO3 Open Loop Phase Noise
-160
-140
-120
-100
-80
-60
-40
-20
1 10 100 1000 10000
Offset Frequency (kHz)
Phase Noise (dBc/Hz)
1600MHz
1400MHz
1200MHz
VCO1 Open Loop Phase Noise
-160
-140
-120
-100
-80
-60
-40
-20
1 10 100 1000 10000
Offset Frequency (kHz)
Phase Noise (dBc/Hz)
2400MHz
2200MHz
2000MHz
VCO1 FVCO versus VT
for the same coarse tune setting
2045
2050
2055
2060
2065
2070
2075
2080
2085
2090
2095
0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8
VT (V)
FVCO (MHz)
-40
80
VCO2 Tuning Gain versus Frequency
0
5
10
15
20
25
30
35
40
1500 1600 1700 1800 1900 2000 2100
FVCO (MHz)
Tuning Gain (MHz/V)
VCO1 Tuning Gain versus Frequency
0
5
10
15
20
25
30
35
40
45
50
1900 2000 2100 2200 2300 2400 2500
FVCO (MHz)
Tuning Gain (MHz/V)
8 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Typical Performance Characteristics: RF Mixers - VDD=3V, T
A=25°C unless stated, as measured on RF2051 evaluation
board, for application schematic see page 36.
RF2051 Typical Operating Current in mA in Full Duplex Mode (both mixers enabled)
MIX1_IDD MIX2_IDD
001 010 011 100 101
001 70 75 80 85 90
010 75 81 86 91 95
011 81 86 91 96 101
100 86 91 97 101 106
101 92 97 102 107 112
Mixer 1 Conversion Gain, IF Output=100MHz
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
250 500 750 1000 1250 1500 1750
RF Input Frequency (MHz)
Conversion Gain (dB)
-40°C
+27°C
+85°C
Operating Current, One Mixer Enabled versus
Temperature and Supply Voltage
50
55
60
65
70
75
80
001 010 011 100 101
Mixer Bias Current Setting (MIX_IDD)
Supply Current (mA)
-40°C, +2.7V
-40°C, +3.0V
-40°C, +3.6V
+27°C, +2.7V
+27°C, +3.0V
+27°C, +3.6V
+85°C, +2.7V
+85°C, +3.0V
+85°C, +3.6V
Gain versus Temperature and Supply Voltage
(excluding losses in PCB and Baluns)
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
-40-20 0 20406080100
Temperature (°C)
Gain (dB)
2.7V
3.0V
3.6V
9 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Typical Performance Characteristics: RF Mixers - VDD=3V, T
A=25°C unless stated, as measured on RF2051 evaluation
board, for application schematic see page 36.
Mixer 1 Noise Figure versus Bias Current
IF Output=100MHz
5
6
7
8
9
10
11
12
13
14
15
250 500 750 1000 1250 1500 1750
RF Input Frequency (MHz)
Noise Figure (dB)
MIX1_IDD = 001
MIX1_IDD = 010
MIX1_IDD = 011
MIX1_IDD = 100
MIX1_IDD = 101
Mixer 1 Input Power for 1dB Compression
versus Temperature and Bias Current Setting
IF Output=100MHz
-2
0
2
4
6
8
10
12
14
250 500 750 1000 1250 1500 1750
RF Input Frequency (MHz)
Pin 1dB (dBm)
-40 Deg C, 001
+27 Deg C, 001
+85 Deg C, 001
-40 Deg C, 011
+27 Deg C, 011
+85 Deg C, 011
-40 Deg C, 101
+27 Deg C, 101
+85 Deg C, 101
Mixer 1 Input IP3 versus Bias Current Setting
0
5
10
15
20
25
30
001 010 011 100 101
Bias Current Setting (MIX1 IDD)
Input IP3 (dBm)
500MHz RF to 100MHz IF
900MHz RF to 100MHz IF
2000MHz RF to 500MHz IF
Mixer 1 Noise Figure versus Temperature
IF Output=100MHz and MIX1_IDD=100
5
6
7
8
9
10
11
12
13
14
15
250 500 750 1000 1250 1500 1750
RF Input Frequency (MHz)
Noise Figure (dB)
-40°C
+27°C
+85°C
IIP3 versus Temperature and Supply Voltage
(Max Linearity)
18.8
19.0
19.2
19.4
19.6
19.8
20.0
20.2
20.4
20.6
-40 -20 0 20 40 60 80 100
Temperature (°C)
IIP3 (dBm)
2.7V
3.0V
3.6V
NF versus Temperature and Supply Voltage
(Low Noise Mode MIX1_IDD=001))
8.0
8.5
9.0
9.5
10.0
10.5
11.0
-40 -20 0 20 40 60 80 100
Temperature (°C)
NF (dB)
2.7V
3.0V
3.6V
10 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Typical Performance Characteristics: RF Mixers - VDD=3V, T
A=25°C unless stated, as measured on RF2051 evaluation
board, for application schematic see page 36.
Mixer Typical LO Leakage at IF Output
IF Output=100MHz
-70
-60
-50
-40
-30
-20
-10
0
0 500 1000 1500 2000 2500
RF Input Frequency (MHz)
LO Leakage (dBm)
-40°C, Path 1
-40°C, Path 2
+27°C, Path 1
+27°C, Path 2
+85°C, Path 1
+85°C, Path 2
Mixer 1 Typical RF and LO Leakage at IF Output
-70
-60
-50
-40
-30
-20
-10
0
250 500 750 1000 1250 1500 1750
RF Input Frequency (MHz)
Level at Mixer 1 Output (dBm)
IF Output at 100MHz
RF Leakage
LO Leakage (High Side)
Full Duplex Mode Typical Isolation Between
Mixers
50
60
70
80
90
100
0 500 1000 1500 2000 2500
RF Frequency (MHz)
Isolation (dB)
Mixer 2 Typical IF and LO Leakage at RF Input
-80
-70
-60
-50
-40
-30
-20
-10
0
250 500 750 1000 1250 1500 1750
RF Input Frequency (MHz)
Level at Mixer 2 Input (dBm)
100MHz IF Leakage to RF Port
LO Leakage (High Side) to RF
Mixer 1 Typical IF and LO Leakage at RF Input
-80
-70
-60
-50
-40
-30
-20
-10
0
250 500 750 1000 1250 1500 1750
RF Input Frequency (MHz)
Level at Mixer 1 Input (dBm)
100MHz IF Leakage to RF Port
LO Leakage (High Side) to RF
Mixer 2 Typical RF and LO Leakage at IF Output
-70
-60
-50
-40
-30
-20
-10
0
250 500 750 1000 1250 1500 1750
RF Input Frequency (MHz)
Level at Mixer 2 Output (dBm)
IF Output at 100MHz
RF Leakage
LO Leakage (High Side)
11 of 40
RF2051
DS120308
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Detailed Description
The RF2051 is a wideband RF frequency converter chip which includes a fractional-N phase-locked loop, a crystal oscillator cir-
cuit, a low noise VCO core, a LO signal multiplexer, two buffer circuits and two RF mixers. Synthesizer programming, device con-
figuration and control are achieved through a mixture of hardware and software controls. All on-chip registers are programmed
through a simple three-wire serial interface.
VCO
The VCO core in the RF2051 consists of three VCOs which, in conjunction with the integrated 2/4 LO divider, cover the LO
range from 300MHz to 2400MHz.
VCO 1, 2, and 3 are selected using the PLL1x0:P1_VCOSEL and PLL2x0:P2_VCOSEL control words. Each VCO has 128 overlap-
ping bands to achieve an acceptable VCO gain (20MHz/V nom) and hence a good phase noise performance across the whole
tuning range. The chip automatically selects the correct VCO band ("VCO coarse tuning") to generate the desired LO frequency
based on the values programmed into the PLL1 and PLL2 registers banks. For information on how to program the desired LO
frequency into the PLL1 and PLL2 banks refer to page 12.
The automatic VCO band selection is triggered every time the ENBL pin is taken high. Once the band has been selected the PLL
will lock onto the correct frequency. During the band selection process fixed capacitance elements are progressively connected
to the VCO resonant circuit until the VCO is oscillating at approximately the correct frequency. The output of this band selection
is made available in the RB1:CT_CAL read-back register. A value of 127 or 0 in this register indicates that the selection was
unsuccessful, this is usually due to the wrong VCO being selected so the user is trying to program a frequency that is outside of
the VCO operating range. A value between 1 and 126 indicates a successful calibration, the actual value being dependent on
the desired frequency as well as process variation for a particular device. The band selection takes approximately 1500 cycles
of the phase detector clock (about 50us with a 26MHz clock). The band select process will center the VCO tuning voltage at
about 1.2V, compensating for manufacturing tolerances and process variation as well as environmental factors including tem-
perature. For applications where the synthesizer is always on and the LO frequency is fixed, the synthesizer will maintain lock
over a +/-60°C temperature range. However it is recommended to re-initiate an automatic band selection for every 30 degrees
change in temperature in order to maintain optimal synthesizer performance. This assumes an active loop filter. If start-up
time is a critical parameter, and the user is always programming the same frequency for the PLL, the calibration result may be
read back from the RB1:CT_CAL register, and written to the PLL1x2:P1_CT_DEF or PLL2x2:P2_CT_DEF registers (depending on
desired PLL register bank). The calibration function must then be disabled by setting the PLL1x0:P1_CT_EN and/or
PLL2x0:P2_CT_EN control words to 0. For further information please refer to the RF205x Calibration User Guide.
When operating using VCO1 for frequencies above 2.2GHz, it is recommended to change the coarse tuning voltage setting,
PLL1x5:P1_CT_V and PLL2x5:P2_CT_V, from the default value of 16 down to 12.
The LO divide ratio is set by the PLL1x0:P1_LODIV and PLL2x0:P2_LODIV control words.
The LO is routed to mixer1, mixer2, or both depending on the state of the MODE pin and the value of CFG1:FULLD.
The current in the VCO core can be programmed using the PLL1x3:P1_VCOI or PLL2x3:P2_VCOI control words. This allows opti-
mization of VCO performance for a particular frequency. For applications where the required LO frequency is above 2GHz it is
recommended that the LO buffer current be increased by setting CFG5:LO1_I and CFG5:LO2_I to 1100 (hex value C).
VCO Tank Inductor VCO Frequency Range DIV 2 DIV 4
1Internal 1800MHz to 2400MHz 900 MHz to 1200 MHz 450MHz to 600MHz
2Internal 1500MHz to 2100MHz 750MHz to 1050MHz 375MHz to 525MHz
3External 1200MHz to 1600MHz* 600MHz to 800MHz 300MHz to 400MHz
*The frequency of VCO3 is set by external inductors and can be varied by the user.
12 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
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Fractional-N PLL
The IC contains a charge-pump based fractional-N phase locked loop (PLL) for controlling the three VCOs. The PLL includes
automatic calibration systems to counteract the effects of process and environmental variations, ensuring repeatable lock-
time and noise performance. The PLL is intended to use a reference frequency signal of 10MHz to 104MHz. A reference
divider (divide by 1 to divide by 7) is supplied and should be programmed to limit the frequency at the phase detector to a max-
imum of 52MHz. The reference divider bypass is controlled by bit CLK DIV_BYP, set low to enable the reference divider and set
high for divider bypass (divide by 1). The remaining three bits CLK DIV<15:13> set the reference divider value, divide by 2
(010) to 7 (111) when the reference divider is enabled.
Two PLL programming banks are provided, the first bank is preceded by the label PLL1 and the second bank is preceded by the
label PLL2. For the RF2051 these banks are used to program mixer 1 and mixer 2 respectively, and are selected automatically
as the mixer is selected (using the MODE pin).
The PLL will lock the VCO to the frequency FVCO according to:
FVCO =NEFF*FOSC/R
where NEFF is the programmed fractional N divider value, FOSC is the reference input frequency, and R is the programmed R
divider value (1 to 7).
The N divider is a fractional divider, containing a dual-modulus prescaler and a digitally spur-compensated fractional sequence
generator to allow fine frequency steps. The N divider is programmed using the N and NUM bits as follows:
First determine the desired, effective N divider value, NEFF:
NEFF=FVCO*R/FOSC
N(9:0) should be set to the integer part of NEFF
. NUM should be set to the fractional part of NEFF multiplied by 224 =16777216.
Example: VCO1 operating at 2220MHz, 23.92MHz reference frequency, the desired effective divider value is:
NEFF=FVCO *R / FOSC=2220 *1 / 23.92=92.80936454849.
The N value is set to 92, equal to the integer part of NEFF, and the NUM value is set to the fractional portion of NEFF multiplied
by 224:
NUM=0.80936454849 * 224 =13,578,884.
Converting N and NUM into binary results in the following:
N = 0 0101 1100
NUM=1100 1111 0011 0010 1000 0100
So the registers would be programmed:
P1_N (or P2_N)=0 0101 1100
P1_NUM_MSB (or P2_NUM_MSB) = 1100 1111 0011 0010
P1_NUM_LSB (or P2_NUM_LSB)=1000 0100
The maximum NEFF is 511, and the minimum NEFF is 15, when in fractional mode. The minimum step size is FOSC/R*224. Thus
for a 23.92MHz reference, the frequency step size would be 1.4Hz. The minimum reference frequency that could be used to
program a frequency of 2400MHz (using VCO1) is 2400/511, 4.697MHz (approx).
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Phase Detector and Charge Pump
The chip provides a current output to drive an external loop filter. An on-chip operational amplifier can be used to design an
active loop filter or a passive design can be implemented. The maximum charge pump output current is set by the value con-
tained in the P1_CP_DEF/P2_CP_DEF field and CP_LO_I.
In the default state (P1_CP_DEF/P2_CP_DEF=31 and CP_LO_I=0) the charge pump current (ICPset) is 120uA. If CP_LO_I is
set to 1 this current is reduced to 30uA.
The charge pump current can be altered by changing the value of P1_CP_DEF/P2_CP_DEF. The charge pump current is
defined as:
ICP= ICPset*CP_DEF / 31
If automatic loop bandwidth correction is enabled the charge pump current is set by the calibration algorithm based upon the
VCO gain. For more information on the VCO gain calibration, which is disabled by default, please refer to the RF205x Calibra-
tion User Guide.
The phase detector will operate with a maximum input frequency of 52MHz.
Note that for high phase detector frequencies, the divider ratio decreases. For N<28 the FLL_FACT register needs to be
changed to 00 from the default value of 01. This is to ensure correct VCO band selection.
Loop Filter
The PLL may be designed to use an active or a passive loop filter as required. The internal configuration of the chip is shown
below. If the CFG1:LF_ACT bit is asserted high, the op-amp will be enabled. If the CFG1:LF_ACT bit is asserted low, the internal
op-amp is disabled and a high impedance is presented to the LFILT1 pin. The RF205x Programming Tool software can assist
with loop filter designs. Because the op-amp is used in an inverting configuration in active mode, when the passive loop filter
mode is selected the phase-detector polarity should be inverted. For active mode, CFG1:PDP=1, for passive mode,
CFG1:PDP=0.
The charge pump output voltage compliance range is typically +0.7V to +1.5V. For applications using a passive loop filter VCO
coarse tuning must be performed regularly enough to ensure that the VCO tuning voltage falls within this compliance range at
all temperatures. The active loop filter maintains the charge pump output voltage in the center of the compliance range, and
the op-amp provides a wider VCO tuning voltage range, typical 0V to +2.4V.
+
-
LFILT1 LFILT2 LFILT3
To VCO Tuning
LF_ACT=TRUE
+1.1V
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Crystal Oscillator
The PLL may be used with an external reference source, or its own crystal oscillator. If an external source (such as a TCXO) is
being used it should be AC-coupled into one of the XO inputs, and the other input should be AC-coupled to ground.
A crystal oscillator typically takes many milliseconds to settle, and so for applications requiring rapid pulsed operation of the
PLL (such as a TDMA system, or Rx/Tx half-duplex system) it is necessary to keep the XO running between bursts. However,
when the PLL is used less frequently, it is desirable to turn off the XO to minimize current draw. The REFSTBY register is pro-
vided to allow for either mode of operation. If REFSTBY is programmed high, the XO will continue to run even when ENBL is
asserted low. Thus the XO will be stable and a clock is immediately available when ENBL is asserted high, allowing the chip to
assume normal operation. On cold start, or if REFSTBY is programmed low, the XO will need a warm-up period before it can pro-
vide a stable clock. The length of this warm-up period will be dependant on the crystal characteristics.
The crystal oscillator circuit contains internal loading capacitors. No external loading capacitors are required, dependant on
the crystal loading specification. The internal loading capacitors are a combination of fixed capacitance, and an array of
switched capacitors. The switched capacitors can be used to tune the crystal oscillator onto the required center frequency and
minimize frequency error. The PCB stray capacitance and oscillator input and output capacitance will also contribute to the
crystal’s total load capacitance. The register settings in the CFG4 register for the switched capacitors are as follows:
• Coarse Tune XO_CT (4 bits) 15*0.55 pF, default 0100
• Fine Step XO_CR_S (1 bit) 1*0.25pF, default 0
The on chip fixed capacitance is approximately 4.2pF.
Wideband Mixer
The RF2051 includes two wideband, double-balanced Gilbert cell mixers. They support RF/IF frequencies of 30MHz to
2500MHz using the internal VCO to provide the LO frequency of 300MHz to 2400MHz. Each mixer has an input port and an
output port that can be used for either IF or RF, i.e. for up conversion or down conversion. The mixer current can be pro-
grammed to between 15mA and 35mA depending on linearity requirements, using the MIX1_IDD<3:0> word for mixer 1 and
the MIX2_IDD<3:0> word for mixer 2, both of which are in the CFG2 register. The majority of the mixer current is sourced
through the output pins via either a centre-tapped balun or an RF choke in the external matching circuitry to the supply.
The RF mixer input and output ports are differential and require simple matching circuits optimized to the specific application
frequencies. A conversion gain of approximately -3dB to 0dB is achieved with 100 differential input impedance, and the out-
puts driving 200 differential load impedance. Increasing the mixer output load increases the conversion gain.
The mixer has a broadband common gate input. The input impedance is dominated by the resistance set by the mixer 1/gm
term, which is inversely proportional to the mixer current setting. The resistance will be approximately 85 at the default mixer
current setting (100). There is also some shunt capacitance at the mixer input, and the inductance of the bond wires to con-
sider at higher frequencies.
The mixer output is high impedance, consisting of a resistance of approximately 2k in parallel with some capacitance. The
mixer output does not need to be matched as such, just to see a resistive load. A higher resistance load will give higher output
voltage and gain. A shunt inductor can be used to resonate with the mixer output capacitance at the frequency of interest. This
inductor may not be required at lower frequencies where the impedance of the output capacitance is less significant. At higher
output frequencies the inductance of the bond wires becomes more significant.
For more information about the mixer port impedances and matching, please refer to the RF205x Family Application Note on
Matching Circuits and Baluns.
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The mixer layout and pin placement has been optimized for high mixer-to-mixer isolation of typically 60dB. The mixers can be
set up to operate in half-duplex mode (1 mixer active) or full duplex mode (both mixers active). The mode selection is done via
hardware control of the MODE pin and by setting the FULLD bit in the CFG1 register as shown in the table below. When in full-
duplex mode, one can either use PLL register bank 1 or 2, the LO signal is routed to both mixers.
Mode Pin FULLD Bit Active PLL Register Bank Active Mixer
Low 0 1 1
High 0 2 2
Low 1 1 Both
High 1 2 Both
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General Programming Information
Serial Interface
All on-chip registers in the RF2051 are programmed using a 3-wire serial bus which supports both write and read operations.
Synthesizer programming, device configuration and control are achieved through a mixture of hardware and software controls.
Certain functions and operations require the use of hardware controls via the ENBL, MODE, and RESETB pins in addition to
programming via the serial bus.
Serial Data Timing Characteristics
Parameter Description Time
t1 Reset delay >5ns
t2 Programming setup time >5ns
t3 Programming hold time >5ns
t4 ENX setup time >5ns
t5 ENX hold time >5ns
t6 Data setup time >5ns
t7 Data hold time >5ns
t8 ENBL setup time >0ns
t9 ENBL hold time >0ns
MCU
ENX
SCLK
SDATA
ENBL
RESETB
MODE
3-wire bus
Hardware
Controls
RF2051
RESETB
ENX
SCLK
SDATA
ENBL
X
Reset
chip
Initial programming of device Programming
updates
Serial bus
X XX X X X X
t1
t2
t3
t4
t5
t8t6 t7 t9
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Write
Initially ENX is high and SDATA is high impedance. The write operation begins with the controller starting SCLK. On the first fall-
ing edge of SCLK the baseband asserts ENX low. The second rising edge of SCLK is reserved to allow the SDI to initialize, and
the third rising edge is used to define whether the operation will be a write or a read operation. In write mode the baseband will
drive SDATA for the entire telegram. RF2051 will read the data bit on the rising edge of SCLK.
The next 7 data bits are the register address, MSB first. This is followed by the payload of 16 data bits for a total write mode
transfer of 24 bits. Data is latched into RF2051 on the last rising edge of SCLK (after ENX is asserted high).
For more information, please refer to the timing diagram on page 16.
The maximum clock speed for a register write is 19.2MHz. A register write therefore takes approximately 1.3us. The data is
latched on the rising edge of the clock. The datagram consists of a single start bit followed by a ‘0’ (to indicate a write opera-
tion). This is then followed by a seven bit address and a sixteen bit data word.
Note that since the serial bus does not require the presence of the crystal clock, it is necessary to insert an additional rising
clock edge before the ENX line is set low to ensure the address/data are read correctly.
Read
Initially ENX is high and SDATA is high impedance. The read operation begins with the controller starting SCLK. The controller is
in control of the SDATA line during the address write operation. On the first falling edge of SCLK the baseband asserts ENX low.
The second rising edge of SCLK is reserved to allow the SDI to initialize, and the third rising edge is used to define whether the
operation will be a write or a read operation. In read mode the baseband will drive SDATA for the address portion of the tele-
gram, and then control will be handed over to RF2051 for the data portion. RF2051 will read the data bits of the address on
the rising edge of SCLK. After the address has been written, control of the SDATA line is handed over to RF2051. One and a half
clocks are reserved for turn-around, and then the data bits are presented by RF2051. The data is set up on the rising edge of
SCLK, and the controller latches the data on the falling edge of SCLK. At the end of the data transmission, RF2051 will release
control of the SDATA line, and the controller asserts ENX high. The SDATA port on RF2051 transitions from high impedance to
low impedance on the first rising edge of the data portion of the transaction (for example, 3 rising edges after the last address
bit has been read), so the controller chip should be presenting a high impedance by that time.
For more information, please refer to the timing diagram on page 16.
The maximum clock speed for a register read is 19.2MHz. A register read therefore takes approximately 1.4us. The address is
latched on the rising edge of the clock and the data output on the falling edge. The datagram consists of a single start bit fol-
A4 A3 A2 A1 A0 D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
ENX
SCLK
SDATA XA6A5
A4 A3 A2 A1 A0 D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
ENX
SCLK
SDATA XA6A5
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lowed by a ‘1’ (to indicate a read operation), followed by a seven bit address. A 1.5 bit delay is introduced before the sixteen bit
data word representing the register content is presented to the receiver.
Note that since the serial bus does not require the presence of the crystal clock, it is necessary to insert an additional rising
clock edge before the ENX line is set low to ensure the address is read correctly.
Hardware Control
Three hardware control pins are provided: ENBL, MODE, and RESETB.
ENBL Pin
The ENBL pin has two functions: to enable the analog circuits in the chip and to trigger the VCO band selection as described in
the VCO section on page 11.
As outlined in the VCO section the chip has a built-in automatic VCO band selection to tune the selected VCO to the desired fre-
quency. The band selection is initiated when the ENBL pin is taken high. Every time the frequency of the synthesizer is re-pro-
grammed, the ENBL has to be inserted high to initiate the automatic VCO band selection (VCO coarse tune).
RESETB Pin
The RESETB pin is a hardware reset control that will reset all digital circuits to their start-up state when asserted low. The
device includes a power-on-reset function, so this pin should not normally be required, in which case it should be connected to
the positive supply.
MODE Pin
The MODE pin controls which mixer(s) and PLL programming register bank is active. See the PLL and Mixer description sec-
tions for details.
ENBL Pin REFSTBY Bit XO and Bias Block Analogue Block Digital Block
Low 0 Off Off On
Low 1 On Off On
High0 OnOnOn
High1 OnOnOn
Parameter Description Time
t1 MODE setup time >5ns
t2 MODE hold time >5ns
ENBL
MODE
t1
t2
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Programming the RF2051
The figure below shows an overview of the device programming.
Note: The set-up processes 1 to 2, 2 to 3, and 3 to 4 are explained further below.
Additional information on device use and programming can be found on the RF205X family page of the RFMD web site
(http://www.rfmd.com/rf205x). The following documents may be particularly helpful:
• RF205x Frequency Synthesizer User Guide
• RF205x Calibration User Guide
Device off
Set-up device
operation
Set operating
frequencies
Set calibration
mode
ENABLE device
Apply power
1
2
3
4
Reset device
Apply power to the device.
Ensure the device is set into a known and correct
state.
To use the device it will be necessary to program the
registers with the desired contents to achieve the
required operating characteristics.
See following sections for details.
When programming is complete the device can be
enabled.
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Start-up
When starting up and following device reset then REFSTBY=0, REFSTBY should be asserted high approximately 500s before
ENBL is taken high. This is to allow the XO to settle and will depend on XO characteristics. The various calibration routines will
also take some time depending on whether they are enabled or not. Coarse tuning calibration takes about 50s and VCO tun-
ing gain compensation takes about 100s. Additionally, time for the PLL to settle will be required. All of these timings will be
dependant upon application specific factors such as loop filter bandwidth, reference clock frequency, XO characteristics and
so on. The fastest turn-on and lock time will be obtained by leaving REFSTBY asserted high, disabling all calibration routines,
and setting the PLL loop bandwidth as wide as possible.
The device can be reset into its initial state (default settings) at any time by performing a hard reset. This is achieved by setting
the RESETB pin low for at least 100ns.
Setting Up Device Operation
The device offers a number of operating modes which need to be set up in the device before it will work as intended. This is
achieved as follows.
Three registers need to be written, taking 3.9us at the maximum clock speed. If the device is used with an active filter in sim-
plex operation it will not be necessary to program CFG1 reducing the programming time to 2.6us.
Set-up device
operation
Disable active
loop filter?
Default
Yes LF_ACT
Set to 0
Program
MIX1_IDD and
MIX2_IDD
Set-up complete
Program XO_CT,
XO_CR_S and
CLK_DIV
Internal
capacitors
used to set
Xtal load
Mixer
linearity
1
2
Full duplex
operation?
Default
Yes FULLD
Set to 1
When setting up the device it is necessary to decide if
an active or passive loop filter will be used in the
phase locked loop. The LF_ACT bit is located in the
CFG1 register and is active by default. Set the phase
detector polarity bit in CFG1since the active filter
inverts the loop filter voltage.
The user must then activate the full duplex mode of
operation if fast frequency switching is required or it is
necessary to have both mixers operating
simultaneously. This bit is also located in the CFG1
register and is inactive by default.
The mixer linearity setting is then selected. The default
value is 4 with 1 being the lowest setting and 5 the
highest. The MIX1_IDD and MIX2_IDD bits are located
in the CFG2 register.
The internal crystal loading capacitors are also
programmed to present the correct load to the crystal.
The capacitance internal to the chip can be varied
from 8-16pF in 0.25pF steps (default=10pF). The
reference divider must also be set to determine the
phase detector frequency (default=1). These bits are
located in the CFG4 register.
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Setting Up VCO Coarse Tuning and Loop Filter Calibration
If the user wishes to disable the VCO coarse tune calibration or enable the loop filter calibration then the following program-
ming operation will need to take place.
Two registers need to be written taking 2.6us at maximum clock speed if the course tuning is deactivated or the loop filter cal-
ibration activated. Since it is necessary to program these registers when setting the operating frequency (see next section) this
operation usually carries no overhead.
The coarse tune calibration takes approximately 50us when using a 26MHz reference clock (it will take proportionally longer if
a slower clock is used, and vice versa).
Disable VCO
coarse tune?
Default
Yes P1_CT_EN,
P2_CT_EN
Set to 00
Set calibration
mode
Operating mode set
Enable loop filter
cal?
Default
Yes Loop filter
calibration
2
3
When setting up the device it is necessary to decide
whether to deactivate the devices' internal VCO
calibration or provide the calibration information
directly. These bits are located in the PLL1x0 and
PLL2x0 registers and are active by default.
It is also necessary to decide whether to activate the
loop filter calibration mode, only necessary when
operating the device over very wide band of
frequencies. These bits are also located in the PLL1x0
and PLL2x0 registers. The default setting assumes an
active loop filter is used.
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Setting The Operating Frequency
Setting the operating frequency of the device requires a number of registers to be programmed.
A total of four registers must be programmed to set the device operating frequency for each path within the device. This will
take 5.2us for each path at maximum clock speed.
To change the frequency of the VCO it will be necessary to repeat these operations. However, if the frequency shift is small it
may not be necessary to reprogram the VCOSEL and LODIV bits reducing the register writes to three per path.
For an example on how to determine the integer and fractional parts of the synthesizer PLL division ratio please refer to the
detailed description of the PLL on page 12.
Set operating
frequencies
Program
P1_VCOSEL,
P2_VCOSEL,
P1_LODIV and
P2_LODIV
Program
P1_N, P2_N
Program
P1_NUM_MSB,
P2_NUM_MSB
Program
P1_NUM_LSB,
P2_NUM_LSB,
P1_CT_DEF,
P2_CT_DEF
Frequency
programmed
3
4
When programming the operating frequency it is
necessary to select the appropriate VCO and LODIV
values. The P1_VCOSEL and P1_LODIV bits are
located in the PLL1x0 register and the corresponding
P2 bits in the PLL2x0 register.
If the LO frequency is above 2GHz the LO path current
(CFG5) should be set to 0xC
The integer part of the PLL division ratio is
programmed into the PLL1x3 and PLL2x3 registers
according to the required synthesizer path.
The MSB of the fractional part of the synthesizer PLL
divider value is programmed into the PLL1x1 and
PLL2x1 registers.
The LSB of the fractional part of the synthesizer PLL
divider value is programmed into the PLL1x2 and
PLL2x2 registers together with the CT_CAL bits if fast
frequency switching is required.
(Depending on required frequency resolution and
coarse tune settings this may not be required.)
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Programming Registers
Register Map Diagram
Reg.
Name R/W Add Data
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
CFG1 R/W 00 LD_EN LD_LEV TVCO PDP LF_ACT CPL CT_POL Res EXT_VCO FULLD CP_LO_I
CFG2 R/W 01 MIX1_IDD MIX1_VB MIX2_IDD MIX2_VB Res KV_RNG NBR_CT_AVG NBR_KV_AVG
CFG3 R/W 02 TKV1 TKV2 Res FLL_FACT CT_CPOLREFSTBY
CFG4 R/W 03 CLK_DIV_BYPASS XO_CT XO_I2 XO_I1 XO_CR_S TCT
CFG5 R/W 04 LO1_I LO2_I T_PH_ALGN
CFG6 R/W 05 SU_WAIT Res
PLL1x0 R/W 08 P1_VCOSEL P1_CT_E
N
P1_KV_E
N
P1_LODI
V
Res P1_CP_DEF
PLL1x1 R/W 09 P1_NUM_MSB
PLL1x2 R/W 0A P1_NUM_LSB P1_CT_DEF Res
PLL1x3 R/W 0B P1_N Res P1_VCOI
PLL1x4 R/W 0C P1_DN P1_CT_GAIN P1_KV_GAIN Res
PLL1x5 R/W 0D P1_N_PHS_ADJ Res P1_CT_V
PLL2x0 R/W 10 P2_VCOSEL P2_CT_E
N
P2_KV__E
N
P2_LODI
V
Res P2_CP_DEF
PLL2x1 R/W 11 P2_NUM_MSB
PLL2x2 R/W 12 P2_NUM_LSB P2_CT_DEF Res
PLL2x3 R/W 13 P2_N Res P2_VCOI
PLL2x4 R/W 14 P2_DN P2_CT_GAIN P2_KV_GAIN Res
PLL2x5 R/W 15 P2_N_PHS_ADJ Res P2_CT_V
GPO R/W 18 Res P1_GPO
1
Res P1_
GPO
3
P1_
GPO
4
Res P2_GP
O1
Res P2_GPO
3
P2_
GPO
4
Res
CHIPREV R 19 PARTNO REVNO
RB1 R 1C LOCK CT_CAL CP_CAL Res
RB2 R 1D V0_CAL V1_CAL
RB3 R 1E RSM_STATE Res
TEST R 1F TEN TMUX CPU CPD FNZ LDO
_BY
P
TSEL Res DACTEST Res
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CFG1 (OOh) - Operational Configuration Parameters
CFG2 (O1h) - Mixer Bias and PLL Calibration
# Bit Name Default Function
15 LD_EN 1 9 Enable lock detector circuitry
14 LD_LEV 0 Modify lock range for lock detector
13 TVCO(4:0) 0 VCO warm-up time=TVCO/(FREF=256)
12 0
11 0 1
10 0
90
8 PDP 1 Phase detector polarity: 0=positive, 1=negative
7 LF_ACT 1 C Active loop filter enable, 1=Active 0=Passive
6 CPL(1:0) 1 Charge pump leakage current: 00=no leakage, 01=low leakage, 10=mid leakage, 11=high
leakage
50
4 CT_POL 0 Polarity of VCO coarse-tune word: 0=positive, 1=negative
300
2 EXT_VCO 0 0=Normal operation 1 =external VCO (VCO3 disabled, KV_CAL and CT_CAL must be dis-
abled)
1 FULLD 0 0=Half duplex, mixer is enabled according to MODE pin, 1=Full duplex, both mixers enabled
0 CP_LO_I 0 0=High charge pump current, 1=low charge pump current
# Bit Name Default Function
15 MIX1_IDD 1 8 Mixer 1 current setting: 000=0mA to 111=35mA in 5mA steps
14 0
13 0
12 MIX1_VB 0 Mixer 1 voltage bias.
11 1 C
10 MIX2_IDD 1 Mixer 2 current setting: 000=0mA to 111=35mA in 5mA steps
90
80
7 MIX2_VB 0 5 Mixer 2 voltage bias
61
50
4 KV_RNG 1 Sets accuracy of voltage measurement during KV calibration: 0=8bits, 1=9bits
3 NBR_CT_AVG 1 8 Number of averages during CT cal
20
1 NBR_KV_AVG 0 Number of averages during KV cal
00
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support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
CFG3 (O2h) - PLL Calibration
CFG4 (O3h) - Crystal Oscillator and Reference Divider
# Bit Name Default Function
15 TKV1 0 0 Settling time for first measurement in LO KV compensation
14 0
13 0
12 0
11 TKV2 0 4 Settling time for second measurement in LO KV compensation
10 1
90
80
700
60
50
40
3 FLL_FACT 0 4 Default setting 01. Needs to be set to 00 for N<28. This case can arise when higher phase
detector frequencies are used.
21
1CT_CPOL 0
0 REFSTBY 0 Reference oscillator standby mode 0=XO is off in standby mode, 1=XO is on in standby mode
# Bit Name Default Function
15 CLK_DIV 0 1 Reference divider, divide by 2 (010) to 7 (111) when reference divider is enabled
14 0
13 0
12 CLK_DIV_BYPASS 1 Reference divider enabled=0, divider bypass (divide by 1)=1
11 XO_CT 1 8 Crystal oscillator coarse tune (approximately 0.5pF steps from 8pF to 16pF)
10 0
90
80
7 XO_I2 0 0 Crystal oscillator current setting
6 XO_I1 0
5 XO_CR_S 0 Crystal oscillator additional fixed capacitance (approximately 0.25pF)
4 TCT 0 Duration of coarse tune acquisition
31F
21
11
01
26 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
CFG5 (O4h) - LO Bias
CFG6 (O5h) - Start-up Timer
# Bit Name Default Function
15 LO1_I 0 0 Local oscillator Path1 current setting
14 0
13 0
12 0
11 LO2_I 0 0 Local oscillator Path2 current setting
10 0
90
80
7 T_PH_ALGN 0 0 Phase alignment timer
60
50
40
304
21
10
00
# Bit Name Default Function
15 SU_WAIT 0 0 Crystal oscillator settling timer.
14 0
13 0
12 0
11 0 1
10 0
90
81
700
60
50
40
300
20
10
00
27 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
PLL1x0 (08h) - VCO, LO Divider and Calibration Select
PLL1x1 (09h) - MSB of Fractional Divider Ratio
# Bit Name Default Function
15 P1_VCOSEL 0 7 Path 1 VCO band select: 00=VCO1, 01=VCO2, 10=VCO3, 11=Reserved
14 1
13 P1_CT_EN 1 Path 1 VCO coarse tune: 00=disabled, 11=enabled
12 1
11 P1_KV_EN 0 1 Path 1 VCO tuning gain calibration: 00=disabled, 11=enabled
10 0
9 P1_LODIV 0 Path 1 local oscillator divider: 00=divide by 1, 01=divide by 2, 10=divide by 4, 11=reserved
81
701
60
5 P1_CP_DEF 0 Charge pump current setting
If P1_KV_EN=11 this value sets charge pump current during KV compensation only
41
31F
21
11
01
# Bit Name Default Function
15 P1_NUM_MSB 0 6 Path 1 VCO divider numerator value, most significant 16 bits
14 1
13 1
12 0
11 0 2
10 0
91
80
707
61
51
41
306
21
11
00
28 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
PLL1x2 (0Ah) - LSB of Fractional Divider Ratio and CT Default
PLL1x3 (0Bh) - Integer Divider Ratio and VCO Current
# Bit Name Default Function
15 P1_NUM_LSB 0 2 Path 1 VCO divider numerator value, least significant 8 bits
14 0
13 1
12 0
11 0 7
10 1
91
81
7 P1_CT_DEF 0 7 Path 1 VCO coarse tuning value, used when P1_CT_EN=00
61
51
41
31E
21
11
00
# Bit Name Default Function
15 P1_N 0 2 Path 1 VCO divider integer value
14 0
13 1
12 0
11 0 3
10 0
91
81
700
60
50
40
302
2 P1_VCOI 0 Path 1 VCO bias setting: 000=minimum value, 111= maximum value
11
00
29 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
PLL1x4 (0Ch) - Calibration Settings
PLL1x5 (0Dh) - More Calibration Settings
# Bit Name Default Function
15 P1_DN 0 1 Path 1 frequency step size used in VCO tuning gain calibration
14 0
13 0
12 1
11 0 7
10 1
91
81
71E
6 P1_CT_GAIN 1 Path 1 coarse tuning calibration gain
51
40
3 P1_KV_GAIN 0 4 Path 1 VCO tuning gain calibration gain
21
10
00
# Bit Name Default Function
15 P1_N_PHS_ADJ 0 0 Path 1 frequency step size used in VCO tuning gain calibration
14 0
13 0
12 0
11 0 0
10 0
90
80
701
60
50
4 P1_CT_V 1 Path 1 course tuning voltage setting when performing course tuning calibration. Default
value is 16. Change to 12 when using VCO1 for frequencies above 2.2GHz.
300
20
10
00
30 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
PLL2x0 (10h) - VCO, LO Divider and Calibration Select
PLL2x1 (11h) - MSB of Fractional Divider Ratio
# Bit Name Default Function
15 P2_VCOSEL 0 7 Path 2 VCO band select: 00=VCO1, 01=VCO2, 10=VC03, 11=Reserved
14 1
13 P2_CT_EN 1 Path 2 VCO coarse tune: 00=disabled, 11= enabled
12 1
11 P2_KV_EN 0 1 Path 2 VCO tuning gain calibration: 00=disabled, 11=enabled
10 0
9 P2_LODIV 0 Path 2 local oscillator divider: 00=divide by 1, 01=divide by 2, 10=divide by 4, 11=reserved
81
71
6
5 P2_CP_DEF 0 Charge pump current setting.
If P2_KV_EN=11 this value sets charge pump current during KV compensation only
41
31F
21
11
01
# Bit Name Default Function
15 P2_NUM_MSB 0 6 Path 2 VCO divider numerator value, most significant 16 bits
14 1
13 1
12 0
11 0 2
10 0
91
80
707
61
51
41
306
21
11
00
31 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
PLL2x2 (12h) - LSB of Fractional Divider Ratio and CT Default
PLL2x3 (13h) - Integer Divider Ratio and VCO Current
# Bit Name Default Function
15 P2_NUM_LSB 0 2 Path 2 VCO divider numerator value, least significant 8 bits.
14 0
13 1
12 0
11 0 7
10 1
91
81
7 P2_CT_DEF 0 7 Path 2 VCO coarse tuning value, used when P2_CT_EN=00
61
51
41
31E
21
11
00
# Bit Name Default Function
15 P2_N 0 2 Path 2 VCO divider integer value
14 0
13 1
12 0
11 0 3
10 0
91
81
700
60
50
40
302
2 P2_VCOI 0 Path 1 VCO bias setting: 000=minimum value, 111= maximum value
11
00
32 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
PLL2x4 (14h) - Calibration Settings
PLL2x5 (15h) - More Calibration Settings
# Bit Name Default Function
15 P2_DN 0 1 Path 2 frequency step size used in VCO tuning gain calibration
14 0
13 0
12 1
11 0 7
10 1
91
81
71E
6 P2_CT_GAIN 1 Path 2 coarse tuning calibration gain
51
40
3 P2_KV_GAIN 0 4 Path 2 VCO tuning gain calibration gain
21
10
00
# Bit Name Default Function
15 P2_N_PHS_ADJ 0 0 Path 2 synthesizer phase adjustment
14 0
13 0
12 0
11 0 0
10 0
90
80
701
60
50
4 P2_CT_V 1 Path 2 course tuning voltage setting when performing course tuning calibration. Default
value is 16. Change to 12 when using VCO1 for frequencies above 2.2GHz.
300
20
10
00
33 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
GPO (18h) - Internal Control Output Settings
CHIPREV (19h) - Chip Revision Information
# Bit Name Default Function
15 0 0
14 P1_GPO1 0 Setting of GPO1 when path 1 is active, used internally only
13 0
12 P1_GPO3 0 Setting of GPO3 when path 1 is active, used internally only
11 P1_GPO4 0 0 Setting of GPO4 when path 1 is active, used internally only
10 0
90
80
700
6 P2_GPO1 0 Setting of GPO1 when path 2 is active, used internally only
50
4 P2_GPO3 0 Setting of GPO3 when path 2 is active, used internally only
3 P2_GPO4 0 0 Setting of GPO4 when path 2 is active, used internally only
20
10
00
# Bit Name Default Function
15PARTNO 00RFMD Part number for device
14 0
13 0
12 0
11 0 0
10 0
90
80
7 REVNO X X Part revision number
6X
5X
4X
3XX
2X
1X
0X
34 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
RB1 (1Ch) - PLL Lock and Calibration Results Read-back
RB2 (1Dh) - Calibration Results Read-Back
# Bit Name Default Function
15 LOCK X X PLL lock detector, 0=PLL locked, 1=PLL unlocked
14 CT_CAL X CT setting (either result of course tune calibration, or CT_DEF, depending on state of CT_EN).
Also depends on the MODE of the device
13 X
12 X
11 X X
10 X
9X
8X
7 CP_CAL X X CP setting (either result of KV cal, or CP_DEF, depending on state of KV_EN).
Also depends on the MODE of the device
6X
5X
4X
3XX
2X
10
00
# Bit Name Default Function
15 VO_CAL X X The VCO voltage measured at the start of a VCO gain calibration
14 X
13 X
12 X
11 X X
10 X
9X
8X
7 V1_CAL X X The VCO voltage measured at the end of a VCO gain calibration
6X
5X
4X
3XX
2X
1X
0X
35 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
RB3 (1Eh) - PLL state Read-Back
TEST (1Fh) - Test Modes
# Bit Name Default Function
15 RSM_STATE X X State of the radio state machine
14 X
13 X
12 X
11 X X
10 X
90
80
700
60
50
40
300
20
10
00
# Bit Name Default Function
15TEN 00Enables test mode
14 TMUX 0 Sets test multiplexer state
13 0
12 0
11 CPU 0 0 Set charge pump to pump up, 0=normal operation 1=pump down
10 CPD 0 Set charge pump to pump down, 0=normal operation 1=pump down
9 FNZ 0 0=normal operation, 1=fractional divider modulator disabled
8 LDO_BYP 0 On chip low drop out regulator bypassed
7TSEL 0 0
60
50
4 DACTEST 0 DAC test
300
20
10
00
36 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Evaluation Board
The following diagrams show the schematic and PCB layout of the RF2051 evaluation board.The standard evaluation board
has been configured for wideband operation. Application notes have been produced showing how the device is matched and
on balun implementations for narrowband applications. The evaluation board is provided as part of a design kit (DK2051),
along with the necessary cables and programming software tool to enable full evaluation of the RF2051.
Evaluation Board Schematic
R3
12 k
C9
470 pF
C8
22 pF
R20
0 R
R19
DNI
R2
820 R
C10
330 pF
R6
820 R
C17
330 pF
Loop Filter
1
3
2
6
5
4
7
8
2527 2630 29 283132
24
22
23
19
20
21
18
17
91110 141312 15 16
R1
51 k
77 strip
77 strip
C5
33 pF
C34
10 nF
VDDA
C35
33 pF
ENBL
R5
DNI
CP_OP
LFILT2
R4
DNI
VTUNE
C36
33 pF
MODE
C16
DNI
GND
GND
3
2
26 MHz XTAL
4
C22
DNI
C7
DNI
J6
REF
T4
C29
100 pF
TC-1-13M
C30
100 pF
C33
DNI
R17
0 R 50 strip J4
RF IP1
C3
33 pF
C19
10 nF
VDDD
C2
33 pF
C18
10 nF
VDDA
L2
DNI
R11
DNI T3
VDDA
C28
100 pF
C26
100 pF
C27
100 pF
C32
DNI
R16
0 R 50 strip J3
RF OP
1
TC1-1-13M
C23
100 pF
T2
C24
100 pF
C31
DNI
R15
0 R 50 strip J2
RF IP2
L1
DNI
R8
DNI T1
TC4-19+
VDDA
C20
100 pF
C21
100 pF
C25
DNI
R14
0 R 50 strip J1
RF OP2
C6
100 pF
C1
33 pF
C13
33 pF
C14
33 pF
C15
33 pF
SDATA SCLK ENX
RESETB
R21
100 k
CB2
CB4
CTS#
12
11
10
9
8
7
6
5
4
3
2
1
DSR#
UIO
13
14
15
16
17
18
19
20
21
22
23
24
CB0
CB1
VCC
RST#
VDD
CB3
PU1
PU2
VCC
USB
SLD
Socket for USB
Interface
13 14
15 16
17 18
19 20
21 22
23 24
HDR_2X12
1211
109
87
65
43
21
VDD
VDD
SCLK
ENX
RESETB
VDDA
ENBL
SDATA
VTUNE
CP_OP
VDDD
MODE
C12
10 uF
C11
10 uF
LFILT1
LFILT2
LFILT3
LFILT1
LFILT3
Component
Designator
60 kHz Active Loop Fil t er
(As Fitted on Evaluation Board)
60 kHz Passive Loop Filter
(Alternative Confi guration)
R3 12 k12 k
C9 470 pF 560 pF
C8 22 pF 39 pF
R19 DNI 3.9 k
R20 0 DNI
R2 820 0
C10 330 pF 0
R6 820 DNI
C17 330 pF 120 pF
Loop Filter Component Values
39 of 40
RF2051
DS120308
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Package Drawing
QFN, 32-Pin, 5mmx5mm
Support and Applications Information
Application notes and support material can be downloaded from the product web page: www.rfmd.com/rf205x.
Ordering Information
Part Number Package Quantity
RF2051 32-Pin QFN 25pcs sample bag
RF2051SB 32-Pin QFN 5pcs sample bag
RF2051SR 32-Pin QFN 100pcs reel
RF2051TR7 32-Pin QFN 750pcs reel
RF2051TR13 32-Pin QFN 2500pcs reel
DK2051 Complete Design Kit 1 box
0.08 C
0.1 C
-C-
0.85±0.10
Detail ‘D’
Rotated CW
Shaded area indicates pin 1.
Dimensions in mm.
0.00
0.05
SEATING
PLANE
-A-
-B-
5.00
5.000
3.70±0.10 0.1 C
MA B
1
0.25 Typ.
0.1 C
MA B
0.23±0.05
32x
10.1 C 0.85±0.10
SEE DETAIL ‘D’
See Detail ‘D’
0.35±0.05
32x
0.50 Typ.
