Broadband Up/Downconverting Mixer with
Integrated Fractional-N PLL and VCO
ADRF6655
Rev. 0
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FEATURES
Broadband active mixer with integrated fractional-N PLL
RF input frequency range: 100 MHz to 2500 MHz
Internal LO frequency range: 1050 MHz to 2300 MHz
Flexible IF output interface
Input P1dB: 12 dBm
Input IP3: 29 dBm
Noise figure (SSB): 12 dB
Voltage conversion gain: 6 dB
Matched 200 Ω output impedance
SPI serial interface for PLL programming
40-lead 6 mm × 6 mm LFCSP
GENERAL DESCRIPTION
The ADRF6655 is a high dynamic range active mixer with
integrated PLL and VCO. The synthesizer uses a programmable
integer-N/fractional-N PLL to generate a local oscillator input
to the mixer. The PLL reference input is nominally 20 MHz. The
reference input can be divided by or multiplied by and then
applied to the PLL phase detector. The PLL can support input
reference frequencies from 10 MHz to 160 MHz. The phase
detector output controls a charge pump whose output is integrated
in an off-chip loop filter. The loop filter output is then applied to an
integrated VCO. The VCO output at 2 × fLO is then applied to a local
oscillator (LO) divider as well as to a programmable PLL divider.
The programmable divider is controlled by an Σ-Δ modulator
(SDM). The modulus of the SDM can be programmed between
1 and 2047.
The broadband, active mixer employs a bias adjustment to allow
for enhanced IP3 performance at the expense of increased supply
current. The mixer provides an input IP3 exceeding 25 dBm
with 12 dB single sideband NF under typical conditions. The IIP3
can be boosted to ~29 dBm with roughly 20 mA of additional
supplied current. The mixer provides a typical voltage conversion
gain of 6 dB with a 200 Ω differential IF output impedance. The
IF output can be externally matched to support upconversion over
a limited frequency range.
The ADRF6655 is fabricated using an advanced silicon-germanium
BiCMOS process. It is packaged in a 40-lead, exposed-paddle,
Pb-free, 6 mm × 6 mm LFCSP. Performance is specified over a
−40°C to +85°C temperature range.
FUNCTIONAL BLOCK DIAGRAM
MUX
RSET NC
LOSEL
LON
LOP
MUX
LOSEL
TEMP
SENSOR
GND
IP3SET
GND
VCCLO
BUFFER
BUFFER
OUTP
V
CCLO
+CHARGE PUM P
250µA,
500µA (DE FAULT),
750µA,
1000µA
PRESCALER
3.3V LDO VCO LDO2.5V LDO
LE
CLK SPI
INTERFACE
DATA
MUXOUT
REFIN
ADRF6655
34
GNDGND
35
19
OUTN
181716
DECL3
40
VTUNE
39
DECL2 VCC2
9105
DECL1
2
VCC1
1
8
6
GND 7
14
GND 15
13
12
38
GND 11
37
36
GND
31
NCNC
32
33
28
VCCMIX
27
INP
26
INN
25
GND
24
GND
23
VCCV2I
22
GND
GND
21
20
29
30
PHASE
FREQUENCY
DETECTOR
THIRD-ORDER
FRACTIONAL
INTERPOLATOR
FRACTION
REG MODULUS INTEGER
REG
N CO UNTER
21 TO 123
GND
4
CP
3
×2
÷2
÷4
DIVIDER
÷2 OR ÷3
VCO
CORE
0
8817-001
Figure 1.
ADRF6655
Rev. 0 | Page 2 of 44
TABLE OF CONTENTS
Features .............................................................................................. 1
General Description ......................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Timing Characteristics ................................................................ 5
Absolute Maximum Ratings ............................................................ 6
ESD Caution .................................................................................. 6
Pin Configuration and Function Despcriptions .......................... 7
Typical Performance Characteristics ............................................. 9
Downconversion ........................................................................... 9
Upconversion .............................................................................. 11
PLL Characteristic ...................................................................... 12
Complimentary Cumulative Distribution Function (CCDF):
Downconversion, LO = 1100 MHz, RF = 900 MHz .............. 14
Complimentary Cumulative Distribution Function (CCDF):
Downconversion, LO = 1700 MHz, RF = 1900 MHz ............ 15
Complimentary Cumulative Distribution Function (CCDF):
Upconversion Distribution ....................................................... 16
Circuit Description ......................................................................... 17
PLL and VCO Block ................................................................... 17
RF Mixer Block ........................................................................... 17
Digital Interfaces ........................................................................ 18
Analog Interfaces ............................................................................ 19
Supply Connections ................................................................... 19
Synthesizer Connections ........................................................... 19
Output Matching and Biasing................................................... 19
Input Matching ........................................................................... 20
IP3SET Linearization Feature ................................................... 21
CDAC Linearization Feature .................................................... 21
External LO Interface ................................................................ 21
Using an External VCO ............................................................. 22
ADRF6655 Control Software ........................................................ 23
PLL Loop Filter Design ............................................................. 23
Register Structure ........................................................................... 24
Device Programming ................................................................. 25
Initialization Sequence .............................................................. 25
Register 0—Integer Divide Control ......................................... 26
Register 1—Modulus Divide Control ...................................... 27
Register 2—Fractional Divide Control .................................... 27
Register 3—Σ-Δ Modulator Dither Control ........................... 28
Register 4—Charge Pump, PFD, and Reference
Path Control ................................................................................ 29
Register 5—LO Path and Mixer Control ................................. 31
Register 6—VCO Control and PLL Enables ........................... 32
Register 7—External VCO Control ......................................... 33
Characterization Setups ................................................................. 34
Evaluation Board Layout and Thermal Grounding ................... 38
Outline Dimensions ....................................................................... 41
Ordering Guide .......................................................................... 41
REVISION HISTORY
2/10—Revision 0: Initial Version
ADRF6655
Rev. 0 | Page 3 of 44
SPECIFICATIONS
VCC = 5 V; ambient temperature (TA) = 25°C; REFIN = 20 MHz, phase frequency detector (PFD) frequency = 20 MHz, IF output loaded
into 4-to-1 transformer matched to a 50 Ω system, unless otherwise noted.
Table 1.
Parameter Test Conditions/Comments Min Typ Max Unit
RF INPUT FREQUENCY RANGE 100 2500 MHz
IF OUTPUT FREQUENCY RANGE Can be matched externally for improved return loss at higher
frequencies (see the Output Matching and Biasing section)
LF 2200 MHz
INTERNAL LO FREQUENCY RANGE Divide-by-3 mode1 1050 1530 MHz
Divide-by-2 mode1 1530 2300 MHz
EXTERNAL LO FREQUENCY RANGE Divide-by-2 mode2 500 2300 MHz
MIXER
Input Return Loss INP, INN; relative to 50 Ω, from 350 MHz to 2200 MHz using
TC1-1-13M+ balun3
12 dB
Output Return Loss OUTP, OUTN; relative to 50 Ω out to 200 MHz using TC4-1W
output transformer option3
12 dB
IF Output Impedance OUTP, OUTN 200 Ω
Output Common Mode OUTP, OUTN; external pull-up balun or inductors required VPOS V
Voltage Conversion Gain IF output loaded into 200 Ω differential load 6 dB
Output Swing 2 V p-p
LO-to-IF Output Leakage Can be improved using external filtering −40 dBm
DYNAMIC PERFORMANCE IP3Set = 3.2 V
Upconversion 340 MHz RF input, 1200 MHz IF output using 1540 MHz
LO (see Figure 56 for output matching network)
Gain Flatness Over ±50 MHz bandwidth for 1200 MHz output center
frequency
0.25 dB p-p
Gain Temperature Coefficient Average values from −40°C to +85°C −10 mdB/°C
Output P1dB 11 dBm
Second-Order Output Intercept (IIP2) 5 dBm each tone 60 dBm
Third-Order Output Intercept (IIP3) −5 dBm each tone, IP3SET = 3.2 V 31 dBm
−5 dBm each tone, IP3SET = open 28 dBm
Output Noise Spectral Density IP3SET = 3.2 V, RF input terminated with 50 Ω −160 dBm/Hz
IP3SET = 3.2 V, RF input = −5 dBm, fLO = 1315 MHz with
fRF = 380 MHz applied, measured noise at fIF = 915 MHz
−155 dBm/Hz
Downconversion 1880 MHz RF input, 140 MHz IF output using 1740 MHz LO
Gain Flatness Over ±50 MHz bandwidth for 1880 MHz input center
frequency
0.25 dB p-p
Gain Temperature Coefficient Average values from −40°C to +85°C −10 mdB/°C
Input P1dB IP3SET = 3.2 V 14 dBm
IP3SET = open 12 dBm
Second-Order Input Intercept (IIP2) −5 dBm each tone 50 dBm
Third-Order Input Intercept (IIP3) −5 dBm each tone, IP3SET = 3.2 V 27 dBm
−5 dBm each tone, IP3SET = open 26 dBm
SSB Noise Figure (NF) IP3SET = 3.2 V 14 dB
IP3SET = open 12 dB
SSB Noise Figure Under Blocking
Conditions
−5 dBm RF input blocker applied at 995 MHz, fLO = 1200 MHz,
noise measured at 5 MHz offset from IF output blocker
IP3SET = 3.2 V 20.75 dB
IP3SET = open 20.25 dB
IF/2 Spurious −5 dBm RF input power −65 dBc
LO OUTPUT LOP, LON
Output Level 1 × LO into a 50 Ω load, LO buffer enabled −7 dBm
ADRF6655
Rev. 0 | Page 4 of 44
Parameter Test Conditions/Comments Min Typ Max Unit
SYNTHESIZER SPECIFICATIONS Synthesizer specifications referenced to 1 × LO4
Fundamental VCO Sensitivity VCO tuning sensitivity before divide-by-2 or divide-by-3 75 MHz/V
Spurs Measured at LO output
Reference/PFD Spurs fPFD/2 −95 dBc
f
PFD −83 dBc
2 × fPFD −85 dBc
4 × fPFD −88 dBc
Phase Noise PFD frequency = 20 MHz4
LO Frequency = 1330 MHz
@ 10 kHz offset −85 dBc/Hz
@ 100 kHz offset −114 dBc/Hz
@ 1 MHz offset −138 dBc/Hz
@ 10 MHz offset −154 dBc/Hz
Integrated Phase Noise 10 kHz to 40 MHz integration bandwidth 0.3 °rms
LO Frequency = 1840 MHz
@ 10 kHz offset −83 dBc/Hz
@ 100 kHz offset −111 dBc/Hz
@ 1 MHz offset −136 dBc/Hz
@ 10 MHz offset −152 dBc/Hz
Integrated Phase Noise 10 kHz to 40 MHz integration bandwidth 0.4 °rms
PFD Frequency 19.33 20 40 MHz
REFERENCE CHARACTERISTICS REFIN, MUXOUT
REFIN Input Frequency 10 20 160 MHz
REFIN Input Capacitance 4 pF
REFIN Input Current ±100 μA
REFIN Input Sensitivity AC-coupled 0.25 1 3.3 V p-p
MUXOUT Output Levels VOL (lock detect output selected) 0.25 V
V
OH (lock detect output selected) 2.7 V
CHARGE PUMP CP
Pump Current Charge pump current adjustable using Register 4 and/or
RSET (see Pin 5 description)
500 μA
Output Compliance Range 1 2.8 V
LOGIC INPUTS CLK, DATA, LE
VINH, Input High Voltage 1.4 3.3 V
VINL, Input Low Voltage 0 0.7 V
IINH/IINL, Input Current ±1 μA
CIN, Input Capacitance 3 pF
POWER SUPPLIES VCC1, VCC2, VCCLO
Voltage Range 4.75 5 5.25 V
Supply Current LO output buffer disabled
PLL only 115 mA
Normal TX mode, IP3SET = 3.2 V, fLO ≤1530 MHz (divide-by-3) 310 mA
Normal TX mode, IP3SET = 3.2 V, fLO > 1530 MHz (divide-by-2) 270 mA
Normal RX mode, IP3SET = open, fLO ≤ 1530 MHz (divide-by-3) 285 mA
Normal RX mode, IP3SET = open, fLO > 1530 MHz (divide-by-2) 245 mA
Power-down mode 15 mA
1 Internal LO path divider programmed via serial interface. See the section for additional information. LO Signal Chain
2 See the section. External LO Interface
3 Improved return loss can be achieved using external matching. See the section for more details. Circuit Description
4 Measured on standard evaluation board with 1.5 kHz loop filter (C13 = 47 nF, C14 = 0.1 μF, C15 = 4.7 μF, R9 = 270 Ω, R10 = 68 Ω).
ADRF6655
Rev. 0 | Page 5 of 44
TIMING CHARACTERISTICS
Table 2. Serial Interface Timing, VCC = 5 V ± 5%
Parameter Limit Unit Test Conditions/Comments
t1 20 ns minimum LE setup time
t2 10 ns minimum DATA to CLK setup time
t3 10 ns minimum DATA to CLK hold time
t4 25 ns minimum CLK high duration
t5 25 ns minimum CLK low duration
t6 10 ns minimum CLK to LE setup time
t7 20 ns minimum LE pulse width
CLK
DATA
LE
DB23 (MSB) DB22 DB2 DB1
(CONTROL BIT C2)(CONTROL BIT C3) DB0 (LSB)
(CONTROL BIT C1)
t2t3
t7
t6t1
t4t5
08817-002
Figure 2. Timing Diagram
ADRF6655
Rev. 0 | Page 6 of 44
ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter Rating
Supply Voltage, VCC 5.5 V
Digital I/O CLK, DATA, LE −0.3 V to +3.6 V
OUTP, OUTN VCC
LOP, LON 16 dBm
INN, INP 20 dBm
DECL3 Using External Bias Option 3.5 V
θJA (Exposed Paddle Soldered Down)1 35°C/W
Maximum Junction Temperature 150°C
Operating Temperature Range −40°C to +85°C
Storage Temperature Range −65°C to +150°C
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
ESD CAUTION
1 Per JDEC standard JESD 51-2. For information on optimizing thermal
impedance, see the Evaluation Board Layout and Thermal Grounding
section.
ADRF6655
Rev. 0 | Page 7 of 44
PIN CONFIGURATION AND FUNCTION DESPCRIPTIONS
VCO
LDO
3.3V
LDO
PD +
CHARGE
PUMP
SERIAL
PORT
PROGRAMMABLE
DIVIDER PRESCALER
MODULUS INTEGER
FRACTION
VCO
BAND
AND
CURRENT
CAL/SET
PFD
2.5V
LDO
÷2 OR ÷3
÷2 OR ÷4
×2
NC = NO CONNECT
1VCC1
2DECL1
3CP
4GND
5RSET
6REFIN
7GND
8MUXOUT
9DECL2
10VCC2
23 GND
24 GND
25 INN
26 INP
27 VCCMIX
28 GND
29 IP3SET
30 GND
22 VCCV2I
21 GND
11
GND
12
DATA
13
CLK
15
GND
17
VCCLO
16
NC
18
OUTN
19
OUTP
20
GND
14
LE
33 NC
34 VCCLO
35 GND
36 GND
37 LON
38 LOP
39 VTUNE
40 DECL3
32 NC
31 GND
ADRF6655
WIDEBAND
UP/DOWN
CONVERTER
MUX
MUX
ENABLE
VCO
CORE
6
6
THIRD-ORDER
SDM
08817-003
Figure 3. Pin Configuration
Table 4. Pin Function Descriptions
Pin No. Mnemonic Description
1 VCC1 Power Supply for Internal 3.3 V LDO. The power supply voltage range is 4.75 V to 5.25 V. Supply pin should
be decoupled with 100 pF and 0.1 μF capacitors located close to the pin.
2 DECL1
Decoupling Node for 3.3 V LDO. Pin should be decoupled with 100 pF, 0.1 μF, and 10 μF capacitors
located close to the pin.
3 CP Charge Pump Output Pin. Connect this pin to VTUNE through the loop filter.
4, 7, 11, 15,
20, 21, 23,
24, 28, 30,
31, 35, 36
GND Ground. Connect these pins to a low impedance ground plane.
ADRF6655
Rev. 0 | Page 8 of 44
Pin No. Mnemonic Description
5 RSET Charge Pump Current. The nominal charge pump current can be set to either 250 μA, 500 μA, 750 μA,
or 1 mA using DB10 and DB11 of Register 4 and by setting DB18 to 0 (internal reference current).
In this mode, no external RSET is required. If DB18 is set to 1, the four nominal charge pump currents
(INOMINAL) can be externally tweaked according to
[]
8.37
250
4.217 ,
×
=Ω BASECP
I
RSET
where ICP, BASE is the base charge pump current in μA.
For further details on the charge pump current,see the Register 4—Charge Pump, PFD, and Reference
Path Control section.
6 REFIN Reference Input. Nominal input level is 1 V p-p. Input range is 10 MHz to 160 MHz. This pin must be
ac-coupled.
8 MUXOUT
Multiplexer Output. This output allows either a digital lock detect, a voltage proportional to temperature,
or a buffered, frequency-scaled reference signal to be accessed externally. The output is selected by
programming the appropriate bits in Register 4.
9 DECL2
Decoupling Node for 2.5 V LDO. Pin should be decoupled with 100 pF, 0.1 μF, and 10 μF capacitors
located close to the pin.
10 VCC2 Power Supply for Internal 2.5 V LDO. The power supply voltage range is 4.75 V to 5.25 V. Supply pin
should be decoupled with 100 pF and 0.1 μF capacitors located close to the pin.
12 DATA Serial Data Input. The serial data input is loaded MSB first with the three LSBs being the control bits.
13 CLK Serial Clock Input. This serial clock input is used to clock in the serial data to the registers. The data
is latched into the 24-bit shift register on the CLK rising edge. Maximum clock frequency is 20 MHz.
14 LE Load Enable. When the LE input pin goes high, the data stored in the shift registers is loaded into one
of the six registers, the relevant latch being selected by the first three control bits of the 24-bit word.
16, 32, 33 NC No Connection.
17, 34 VCCLO Power Supply for LO Path. The power supply voltage range is 4.75 V to 5.25 V. Supply pin should be
decoupled with 100 pF and 0.1 μF capacitors located close to the pin.
18,19 OUTN, OUTP Mixer IF Outputs. These pins should be pulled to VCC with RF chokes.
22 VCCV2I Power Supply for Voltage to Current Input Stage. The power supply voltage range is 4.75 V to 5.25 V.
Supply pin should be decoupled with 100 pF and 0.1 μF capacitors located close to the pin.
25, 26 INN, INP Mixer RF Inputs. Differential RF Inputs. Internally matched to 50 Ω. This pin must be ac-coupled.
27 VCCMIX
Power Supply for Mixer. The power supply voltage range is 4.75 V to 5.25 V. Supply pin should be
decoupled with 100 pF and 0.1 μF capacitors located close to the pin.
29 IP3SET Connect Resistor to VCC to Adjust IP3.
37, 38 LON, LOP Local Oscillator Input/Output. The internally generated 1 × fLO is available on these pins. When internal
LO generation is disabled, an external 2 × fLO or 3 × fLO (depending on divider selection) can be applied
to these pins. This pin must be ac-coupled.
39 VTUNE VCO Control Voltage Input. This pin is driven by the output of the loop filter. Nominal input voltage
range on this pin is 1 V to 2.8 V.
40 DECL3 Decoupling Node for VCO LDO. Connect a 100 pF capacitor and a 10 μF capacitor between this pin
and ground.
EPAD (EP) The exposed paddle should be soldered to a low impedance ground plane.
ADRF6655
Rev. 0 | Page 9 of 44
TYPICAL PERFORMANCE CHARACTERISTICS
VS = 5 V, TA = 25°C, PFD = 20 MHz, REFIN = 20 MHz, IP3SET = 3.2 V, unless otherwise noted.
DOWNCONVERSION
Measured using typical downconversion circuit schematic with high-side LO and 140 MHz IF output, unless otherwise noted.
–5
–4
–3
–2
–1
0
1
2
3
4
5
GAIN (dB)
INPUT FREQUENC Y (MHz)
+25°C
–40°C
+85°C
900 1100130015001700190021002300
LOW-SIDE LO
HIG H-S I DE L O
08817-086
Figure 4. Conversion Gain vs. Input Frequency
10
12
14
16
18
20
NOI SE F I G URE (d B)
RF FREQ UE NC Y ( MHz)
+25°C
–40°C
+85°C
IP 3S ET = 3.2V
IP3SET = OPEN
900 1100 1300 1500 1700 1900 2100
08817-123
Figure 5. SSB Noise Figure vs. RF Frequency
10
12
14
16
18
20
22
24
26
28
30
–50 –45 –40 –35 –30 –25 –20 –15 –10 –5 0
NOI SE FIGURE ( dB)
CW BL OCKER L E V EL (dBm)
IP 3S E T = 3.2V
IP3SET = OPEN
08817-104
Figure 6. SSB Noise Figure vs. CW Blocker Level
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
INPUT IP3 (dBm)
INPUT FRE QUENCY ( MHz )
+25°C
–40°C
+85°C
IP 3S E T = 3 .2V
IP3SET = OPEN
900 1100 1300 1500 1700 1900 2100
08817-087
Figure 7. Input IP3 vs. Input Frequency
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
INPUT FREQUENCY (MHz)
900 1100 1300 1500 1700 1900 2100 2300 2500
+25°C
–40°C
+85°C
LOW-SIDE LO
HIG H- S IDE L O
INPUT IP2 (dBm)
0
8817-088
Figure 8. Input IP2 vs. Input Frequency
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
INPUT P1 dB (dBm)
INPUT FREQUENCY (MHz)
IP 3S E T = 3 .2V
IP3SET = OPEN +25°C
–40°C
+85°C
900 1100 1300 1500 1700 1900 2100
08817-089
Figure 9. Input P1dB vs. Input Frequency
ADRF6655
Rev. 0 | Page 10 of 44
–45
–40
–35
–30
–25
–20
–15
–10
–5
0
0 500 1000 1500 2000 2500 3000
FREQUENCY (MHz )
S11 (dB)
08817-122
Figure 10. RF Port Input Return Loss (S11) vs.
Frequency Measured through TC1-1-13M+
50 100 150 200 250 300 350 400 4500500
30
60
90
120
150
180
210
240
270
0
300
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
0
2.0
FRE QUENC Y ( MHz)
OUTPUT RES ISTANCE ( )
OUT P UT CAPACITANCE (pF )
08817-124
Figure 11. IF Port Output Impedance vs. Frequency
–100
–95
–90
–85
–80
–75
–70
–65
–60
–55
–50
–45
40
1050 1250 1450 1650 1850 2050 2250
LO-TO-RF INPUT LEAKAG E (dBm)
LO FREQUENCY (MHz)
+25°C
–40°C
+85°C
08817-090
Figure 12. LO-to-RF Input Port Leakage vs. LO Frequency
0
20
40
60
80
100
120
140
160
180
200
220
240
260
280
300
320
340
360
380
400
1050 1250 1450 1650 1850 2050 2250
SUPPLY CURRENT (mA)
LO FREQUENCY (M Hz )
+25°C
–40°C
+85°C
IP 3SE T = 3.2 V
IP3SET = OPEN
08817-091
Figure 13. Supply Current vs. LO Frequency
–20
–19
–18
–17
–16
–15
–14
–13
–12
–11
–10
–9
–8
–7
–6
–5
–4
–3
–2
–1
0
1050 1250 1450 1650 1850 2050 2250
LO OUTPUT P OWE R ( dBm)
LO FREQ UENCY (MHz)
+25°C
–40°C
+85°C
08817-092
Figure 14. LO Port Output Power vs. LO Frequency
–80
–75
–70
–65
–60
–55
–50
–45
–40
–35
–30
–25
20
1050 1150 1250 1350 1450 1550 1650 1750 1850 1950 2050 2150 2250
LO F REQUENCY (MHz)
LO -TO- IF OUT PUT L E AKAG E (dBm)
+25°C
–40°C
+85°C
08817-014
Figure 15. LO-to-IF Output Port Leakage vs. LO Frequency
ADRF6655
Rev. 0 | Page 11 of 44
UPCONVERSION
Measured using typical upconversion circuit schematic with high-side LO and 340 MHz RF input, unless otherwise noted.
O UT PUT FRE QUE NC Y ( M Hz )
–5
–4
–3
–2
–1
0
1
2
3
4
5
710 810 910 1010 1110 1210 1310 1410 1510 1610
GAIN (dB)
+25°C
–40°C
+85°C
0
8817-093
Figure 16. Conversion Gain vs. Output Frequency
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
1050 1150 1250 1350 1450 1550 1650 1750 1850 1950 2050 2150 2250
LO FRE QUENCY (M Hz )
fLO
– 2 ×
fRF
SPURIOUS RESPONSE ( dBc)
+25°C
–40°C
+85°C
08817-016
Figure 17. fLO − 2 × fRF Spurious Response vs.
LO Frequency (Relative to IF Output Power)
–80
–70
–60
–50
–40
–30
–20
–10
0
1050 1150 1250 1350 1450 1550 1650 1750 1850 1950 2050
LO FR EQUENCY (MHz )
+25°C
–40°C
+85°C
LO-TO-I F OUTPUT LE AKAG E (dBm)
08817-105
Figure 18. LO-to-IF Output Leakage vs. Frequency
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
710 810 910 1010 1110 1210 1310 1410 1510 1610
O UTP UT FRE QUENCY (MHz)
+25°C
–40°C
+85°C
IP 3S E T = 3 .2V
IP3SET = OPEN
OUTPUT IP3 (dBm)
0
8817-094
Figure 19. Output IP3 vs. Output Frequency
710 810 910 1010 1110 1210 1310 1410 1510 1610
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
OUTPUT FREQ UE NCY ( M Hz )
+25°C
–40°C
+85°C
IP 3S E T = 3.2V
IP3SET = OPEN
OUTPUT P1dB (dBm)
08817-095
Figure 20. Output P1dB vs. Output Frequency
–170
–160
–150
–140
–130
–120
–110
100
710 810 910 1010 1110 1210 1310 1410 1510 1610
NOI S E S P ECTRAL DENS ITY ( dBm/Hz )
OUTPUT F REQUENCY ( M Hz )
0
8817-121
Figure 21. Output Noise Spectral Density vs. Output Frequency
ADRF6655
Rev. 0 | Page 12 of 44
PLL CHARACTERISTIC
Measured using typical downconversion circuit schematic with high-side LO and 140 MHz IF output, loop filter = 1.5 kHz, unless
otherwise noted.
PHASE NO ISE (dBc/ Hz)
–170
–160
–150
–140
–130
–120
–110
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
1k 10k 100k 1M 10M 100M
OFFS E T FRE QUENCY ( kHz )
LO = 2275M Hz
LO = 1100M Hz
+25°C
–10°C
–40°C
+70°C
+85°C
08817-021
Figure 22. Typical Fractional-N Phase Noise Plot
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1050 1150 1250 1350 1450 1550 1650 1750 1850 1950 2050 2150 2250
LO FR EQUENCY (MHz )
INTEGR
A
TED P HAS E NOIS E C rms)
+25°C
–10°C
–40°C
+70°C
+85°C
08817-022
Figure 23.10 kHz to 40 MHz Integrated Phase Noise vs. LO Frequency
025
TIME (ms)
FREQUENCY DEVI
A
TION FROM 2.29GHz (Hz)
–2500
2500
–2000
2000
–1500
1500
–1000
1000
–500
500
2.290G
1
1: 10ms 2.289999883GHz
10
08817-120
Figure 24. Lock Time for 10 MHz Step with 1.5 kHz Loop Filter
–110
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
1050 1250 1450 1650 1850 2050 2250
LO REF E RENCE PF D SP URS (d Bc)
LO FREQ UENCY (MHz)
1 × PFD OFFSET
2 × PFD OFFSET
4 × PFD OFFSET
+25°C
–40°C
+85°C
08817-096
Figure 25. LO Reference/PFD Spurs vs. LO Frequency
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
1050 1150 1250 1350 1450 1550 1650 1750 1850 1950 2050 2150 2250
LO F REQUENCY (M Hz )
VTUNE ( V)
+25°C
–40°C
+85°C
HIG H- S IDE L O
LOW-SIDE LO
08817-025
Figure 26. Tuning Voltage vs. LO Frequency
1.3
1.4
1.5
1.6
1.7
1.8
1.9
–40 –30 –20 –10 0 10 20 30 40 50 60 70 80
VPT
A
T (V)
TEMPERAT URE ( °C)
LO = 1100M Hz , I P 3SET = 3.2V
LO = 2300MHz , IP3SE T = 3.2V
LO =2300M Hz , I P 3S ET = OPEN
0
8817-097
Figure 27. VPTAT MUXOUT Voltage vs. Temperature
ADRF6655
Rev. 0 | Page 13 of 44
–150
–145
–140
–135
–130
–125
–120
–115
–110
–105
–100
–95
–90
–85
–80
–75
–70
–65
60
PHASE NOISE (dBc/ Hz)
AVERAGE
AVERAGE + 3 × ST DEV
10kHz O FF SET
100kHz O F F S E T
1MHz OFFSET
1050 1150 1250 1350 14501550 1650 1750 1850 1950 2050 2150 2250
LO FREQUENCY (M Hz )
08817-039
Figure 28. −40°C Spot Phase Noise vs. LO Frequency
–150
–145
–140
–135
–130
–125
–120
–115
–110
–105
–100
–95
–90
–85
–80
–75
–70
–65
60
PHASE NOISE (dBc/Hz)
AVERAGE
AVERAGE + 3 × ST DEV
10kHz O FF S E T
100kHz O F F S E T
1MHz OFFSET
1050 1150 1250 1350 14501550 1650 1750 1850 1950 2050 2150 2250
LO FREQUENCY (M Hz )
08817-040
Figure 29. −10°C Spot Phase Noise vs. LO Frequency
–150
–145
–140
–135
–130
–125
–120
–115
–110
–105
–100
–95
–90
–85
–80
–75
–70
–65
60
PHASE NOISE (dBc/Hz)
AVERAGE
AVERAGE + 3 × ST DEV
10kHz O FF S E T
100kHz O F F S E T
1MHz OFFSET
1050 1150 1250 1350 14501550 1650 1750 1850 1950 2050 2150 2250
LO FREQUENCY (M Hz )
08817-041
Figure 30. 25°C Spot Phase Noise vs. LO Frequency
–150
–145
–140
–135
–130
–125
–120
–115
–110
–105
–100
–95
–90
–85
–80
–75
–70
–65
60
PHASE NOISE (dBc/Hz)
AVERAGE
AVERAG E + 3 × ST DEV
10kHz OFFSE T
100kHz O FF SET
1MHz OFFSE T
1050 1150 1250 1350 14501550 1650 1750 1850 1950 2050 2150 2250
LO FREQUENCY (M Hz )
08817-042
Figure 31. 70°C Spot Phase Noise vs. LO Frequency
–150
–145
–140
–135
–130
–125
–120
–115
–110
–105
–100
–95
–90
–85
–80
–75
–70
–65
60
PHASE NOISE (dBc/Hz)
AVERAGE
AVERAG E + 3 × S T DEV
10kHz O FF S E T
100kHz O FF SET
1MHz OFFSE T
1050 1150 1250 1350 1450 1550 1650 1750 1850 1950 2050 2150 2250
LO FREQUENCY (M Hz )
08817-043
Figure 32. 85°C Spot Phase Noise vs. LO Frequency
ADRF6655
Rev. 0 | Page 14 of 44
COMPLIMENTARY CUMULATIVE DISTRIBUTION FUNCTION (CCDF): DOWNCONVERSION, LO = 1100 MHz,
RF = 900 MHz
VS = 5 V, TA = 25°C, PFD = 20 MHz, REFIN = 20 MHz, IP3SET = open, as measured using typical downconversion circuit schematic with
high-side LO and 200 MHz IF output, unless otherwise noted.
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
–10 –8 –6 –4 –2 0 2 4 6 8 10 12 14 16 18 20
DISTRI BUTION PERCE NTAGE (%)
GAIN (dB), INPUT P1dB (dBm)
GAIN
+25°C
–40°C
+85°C
IP 3SE T = 3.2V
IP3SET = OPEN
INPUT P1dB
08817-106
Figure 33. Gain and Input P1dB CCDF
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
DISTRI BUTION PERCE NTAGE (%)
INPUT IP3 (dBm)
+25°C
–40°C
+85°C
IP 3S E T = 3.2V
IP3SET = OPEN
0
8817-107
Figure 34. Rx Input IP3 CCDF
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
–100 –95 –90 –85 –80 –75 –70 –65 –60 –55 –50
DISTRIBUTION PERCE N TAGE (%)
LO -TO-RF LEAKAG E (dBm)
+25°C
–40°C
+85°C
08817-098
Figure 35. Rx LO-to-RF Leakage CCDF
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
0 2 4 6 8 101214161820
DISTRIBUTI ON PERCEN TAGE (%)
NOISE F IG URE (dB)
+25°C
–40°C
+85°C
IP3 SE T = 3.2V
IP3SET = OPEN
08817-108
Figure 36. Noise Figure CCDF
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
DISTRI BUTION PERCE NTAGE (%)
+25°C
–40°C
+85°C
IP 3S E T = 3 .2V
IP3SET = OPEN
VPTAT (V)
0
8817-109
Figure 37. VPTAT MUXOUT Voltage
ADRF6655
Rev. 0 | Page 15 of 44
COMPLIMENTARY CUMULATIVE DISTRIBUTION FUNCTION (CCDF): DOWNCONVERSION, LO = 1700 MHz,
RF = 1900 MHz
VS = 5 V, TA = 25°C, PFD = 20 MHz, REFIN = 20 MHz, IP3SET = open, as measured using typical downconversion circuit schematic with
high-side LO and 200 MHz IF output, unless otherwise noted.
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
–5 –4 –3 –2 –1 0 1
GAIN, INPUT P1dB (dB, dBm)
DISTRIBUTION PERCE N TAGE (%)
+25°C
–40°C
+85°C
IP 3S ET = 3.2V
IP3SET = OPEN
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
GAIN INPUT P1dB
0
8817-033
Figure 38. Gain and Input P1dB
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
INPUT IP3 (dBm)
DISTRIBUTION PERCE N TAGE (%)
+25°C
–40°C
+85°C
IP 3S ET = 3.2V
IP3SET = OPEN
20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
08817-034
Figure 39. Rx Input IP3
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
DISTRIBUTION PERCE N TAGE (%)
–100 –90 –80 –70 –60 –50 –40 –30
+25°C
–40°C
+85°C
IP 3S E T = 3.2V
IP3SET = OPEN
LO-TO-RF LEAKAGE (dBm)
08817-099
Figure 40. Rx LO-to-RF Leakage
01234567891011121314151617181920
NOI SE F I G URE (dB)
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
DISTRIBUTION PERCE N TAGE (%)
+25°C
–40°C
+85°C
IP 3S E T = 3.2V
IP3SET = OPEN
08817-110
Figure 41. Rx Noise Figure CCDF
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
VPTAT (V)
DISTRIBUTION PERCE N TAGE (%)
+25°C
–40°C
+85°C
IP 3S ET = 3.2V
IP3SET = OPEN
0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3 2.5
08817-038
Figure 42. VPTAT MUXOUT Voltage
ADRF6655
Rev. 0 | Page 16 of 44
COMPLIMENTARY CUMULATIVE DISTRIBUTION FUNCTION (CCDF): UPCONVERSION DISTRIBUTION
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
–10 –8 6 –4 –2 0 2 4 6 8 10 12 14 16 18 20
DISTRIBUTI ON PERCE NTAGE (%)
GAIN
+25°C
–40°C
+85°C
IP3SET = 3.2V
IP3SET = OPEN
GAIN (dB), OUTPUT P1dB (dBm)
OUTPUT P1dB
08817-100
Figure 43. Gain and Output P1dB CCDF, LO = 1220 MHz, RF = 340 MHz
0
10
20
30
40
50
60
70
80
90
100
0 5 10 15 20 25 30 35 40 45 50 55 60
DISTIBUTION PERCE NTAGE (%)
OUT P UT I P 3 (dBm)
+25°C
–40°C
+85°C
IP 3SE T = 3.2 V
IP3SET = OPEN
0
8817-101
Figure 44. Output IP3 CCDF, LO = 1220 MHz, RF = 340 MHz
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
–100 –90 –80 –70 –60 –50 –40 –30 –20 –10
DIST RI BUT IO N PERCEN TAGE (%)
LO -TO- I F O UT PUT L EAKAG E (d Bm)
+25°C
–40°C
+85°C
IP3SET = 3. 2V
IP3SET = OPEN
08817-113
Figure 45. LO-to-IF Output Leakage CCDF, LO = 1220 MHz, RF = 340 MHz
0
10
20
30
40
50
60
70
80
90
100
108–6–4–2 0 20
DISTRI BUTION PERCEN TAGE (%)
+25°C
–40°C
+85°C
IP3 SET = 3 .2V
IP3 SET = O PEN
GAIN (dB), OUTPUT P1dB (dBm)
GAIN OUTPUT P1dB
2 4 6 8 10 12 14 16 18
08817-102
Figure 46. Gain and Output P1dB CCDF, LO = 1840 MHz, RF = 340 MHz
0
10
20
30
40
50
60
70
80
90
100
DISTRIBUTION PERCE N TAGE (%)
0 1020304050605 1525354555
+25°C
–40°C
+85°C
IP 3S E T = 3.2V
IP3SET = OPEN
OUTPUT IP3 ( dBm)
0
8817-103
Figure 47. Output IP3 CCDF, LO = 1840 MHz, RF = 340 MHz
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
–100 –90 –80 –70 –60 –50 –40 30 –20 –10 0
DISTRIBUTION PERCE N TAGE (%)
LO-TO-IF P ORT LEAKAG E ( dBm)
+25°C
–40°C
+85°C
IP 3S ET = 3.2V
IP3SET = OPEN
08817-114
Figure 48. LO-to-IF Output Leakage CCDF, LO = 1840 MHz, RF = 340 MHz
ADRF6655
Rev. 0 | Page 17 of 44
CIRCUIT DESCRIPTION
The ADRF6655 can be subdivided into a PLL and VCO block
and a mixer block. A detailed circuit description for each block
follows.
PLL AND VCO BLOCK
The PLL and VCO block, shown in Figure 49, is made up of a
reference input block, a phase and frequency detector (PFD), a
charge pump, a VCO, and a divide-by-N modulus block. An
off-chip loop filter completes the loop.
LOOP
FILTER
PRESCALER
ADRF6655 PLL BL OCK DI AGRAM
BAND
SELECT
TO MIXER
BLOCk
CP
CP
VTUNE
PFD
REFIN
FRAC MOD INT
PROGRAMMABLE
DIVIDER
THIRD-ORDER
INTERPOLATOR
×2
÷2
÷4
0
8817-051
Figure 49. PLL and VCO Block
The VCO is implemented with a single core that consists of 64
overlapping bands, as shown in Figure 50. The correct band is
selected automatically by the VCO band calibration circuit when
Register R0, Register R1, or Register R2 is programmed. The
VCO band selection takes roughly 4000 PFD cycles. During
calibration, an internal mux is used to disconnect the VCO input
voltage from the VTUNE pin and apply an internal reference
voltage for calibration. When calibration is complete, the VCO
input voltage is reconnected to the VTUNE pin and normal
PLL operation resumes.
1.4
1.6
1.8
2.0
2.2
2.4
0.51.01.52.02.5
V
TUNE
(V)
f
VCO
/2 (GHz)
08817-052
Figure 50. fVCO/2 vs. Tuning Voltage for All 64 Bands
The VCO operates at twice the LO frequency for improved
isolation. The nominal value of Kv is 75 MHz/V at the VCO
output. As the VCO band is changed from 0 to 63, the size of the
varactor is also changed, thus maintaining a roughly constant
Kv across the entire operating range.
RF MIXER BLOCK
VCC
LO
133133
VCO
ADRF6655 MIX ER BLO CK
÷2 OR ÷3
SIF CDAC V2I
OUTN
OUTP
RFIN
IP3SET
08817-053
Figure 51. Mixer Block
The mixer portion of the ADRF6655, shown in Figure 51, consists
of an LO signal chain, an RF voltage-to-current (V-to-I) converter,
and a mixer core. The LO chain receives a signal from either the
internal VCO or an external LO source. This LO signal then passes
through a frequency divider, which can be set to divide-by-2
or divide-by-3, depending on the desired LO frequency. The
differential RF inputs are converted into currents by the V-to-I
converter and fed into the mixer core. A pair of 133 Ω pull-up
resistors are used to present a ~250 Ω source impedance at the
IF output.
LO Signal Chain
The LO chain consists of a mux that selects between the internal
VCO and an external LO source. The LO signal can then be
divided by 2 or divided by 3, providing a wide range of LO
frequencies from 1050 MHz to 2300 MHz. A buffer then drives
this divided down signal to the mixer core. The LO signal can
also be observed via the LO I/O port when the internal VCO
is selected. When the external LO buffer is enabled, the supply
current and die temperature increase, resulting in a slight
degradation of RF performance. In normal operation mode,
the external LO buffer should be disabled to help minimize
power consumption and provide optimal RF performance.
ADRF6655
Rev. 0 | Page 18 of 44
V-to-I Converter
The differential RF input signal is applied to a pair of resistively
degenerated common-emitter stages, which converts the
differential input voltage to output currents. The input stage also
provides 50 Ω termination to the RF input port. The linearity
of this V-to-I stage can be optimized for a given frequency with
Pin IP3SET at the expense of power dissipation and noise figure.
An additional way of improving linearity without affecting
power dissipation or noise figure is provided by the CDAC
signal controlled by serial port interface (SPI).
Mixer Core
The mixer core, based on the Gilbert cell design of four cross-
connected transistors, takes the currents from the V-to-I stage
and mixes them with the LO signal. This mixer core can be used
as a downconvert mixer as is or as an upconvert mixer with an
off-chip matching network for a given frequency range.
DIGITAL INTERFACES
The ADRF6655 provides access to the many programmable
features available within the IC using a 3-wire SPI control
interface. The minimum delays and hold times are presented
in the timing diagram in Figure 2. The SPI interface provides
digital control of the internal PLL/VCO as well as several other
features related to the mixer core, on-chip referencing, and available
system monitoring functions. The MUXOUT pin provides access
to several output signals that can be selected via the SPI interface.
The available outputs are buffered, frequency-scaled versions of
the reference, a PLL lock-detect signal, and an internal voltage
that is proportional to the IC junction temperature. Details
regarding the register settings and initialization sequence are
included in the Register Structure section.
NC = NO CONNECT
VCC1
DECL1
CP
GND
RSET
RSET
V
SET
REFIN
EXTERNAL
REFERENCE
RF INPUT
MONITOR
OUTPUT
SPI
CONTROL
GND
MUXOUT
DECL2
VCC2
GND
DATA
CLK
GND
VCCLO
NC
OUTN
OUTP
GND
LE
NC
VCCLO
GND
GND
LON
LOP
VTUNE
DECL3
NC
GND
33
34
35
36
37
38
39
40
32
31
23
GND
24
GND
25
INN
26
INP
ADRF6655
27
VCCMIX
28
GND
29
IP3SET
CHARGE PUM P
LOOP FILTER +5V
30
GND
22
VCCV2I
21
GND
11
12
13
15
17
16
18
19
20
14
1
2
3
4
5
6
7
8
9
10
+5V
+5V
+5V
+5V
IF OUTPUT
MATCHING
BALUN AND BI AS IF OUTPUT
+5V
RF I NPUT
MATCHING
BALUN
08817-054
Figure 52. Basic Circuit Connections
ADRF6655
Rev. 0 | Page 19 of 44
ANALOG INTERFACES
The basic circuit connections for a typical ADRF6655 application
are presented in Figure 52.
SUPPLY CONNECTIONS
The ADRF6655 has several supply connections and on-board
regulated reference voltages that should be bypassed to ground
using low inductance bypass capacitors located in close proximity
to the supply and reference pins of the ADRF6655. Specifically
Pin 1, Pin 2, Pin 9, Pin 10, Pin 17, Pin 22, Pin 27, and Pin 40
should be bypassed to ground using individual bypass capacitors.
Pin 9 is the supply used for the on-board VCO, and for best
phase noise performance, several bypass capacitors ranging
from 100 pF to 10 μF may help to improve phase noise
performance. For additional details on bypassing the supply
nodes, refer to the evaluation board schematic in Figure 82.
SYNTHESIZER CONNECTIONS
The ADRF6655 includes an on-board VCO and PLL for LO
synthesis. An external reference must be applied for the PLL to
operate. The external reference should be ac-coupled and provide a
~1 V p-p nominal input level at Pin 6. The reference is compared
to an internally divided version of the VCO output frequency to
create a charge pump error current to control and lock the VCO. The
charge pump output current is filtered and converted to a VTUNE
control voltage through the external loop filter. ADIsimPLL™
can be a helpful tool when designing the external charge pump
loop filter. The typical Kv of the VCO, the charge pump output
current magnitude, and PFD frequency should all be considered
when designing the loop filter. The charge pump current magnitude
can be set internally or with an external RSET resistor connected
to Pin 5 and ground, along with the internal digital settings
applied to the PLL (see the Register 4—Charge Pump, PFD, and
Reference Path Control section for more details).
OUTPUT MATCHING AND BIASING
The ADRF6655 output stage consists of collector connected
output transistors with on-board pull-up resistors. The output
transistors and pull-up network presents a 200 Ω differential
output impedance in parallel with a small amount of shunt
capacitance. The measured RC equivalent impedance of Pin 18
and Pin 19 is ~250 Ω//1.5 pF. This impedance needs to be taken
into consideration when designing the external output matching
network. In addition to matching the presented output source
impedance to the intended load impedance, it is important to
provide pull-up choke connections to the supply pins to allow
for dc current to directly supply the mixer output transistors.
The reactance of the pull-up chokes may need to be considered
when designing the output matching network. For convenience,
several output matching/bias networks are presented in Figure 53
through Figure 58 for reference.
OUTN
OUTP
GND
ADRF6655
T3
850MHz OUT P UT I NTERFACE
+VCC
1.5pF
GJM
15nH
0302CS
12nH
0302CS
12nH
0302CS
TC4-14G2+
2.7pF
GJM
1nF IF OUT
18 19 20
08817-055
Figure 53. 850 MHz Output Matching Network Using the Center-Tap of the
TC4-14T+ Transformer for Biasing the Open Collector Outputs (Output
return loss measured to be better than 12 dB from 800 MHz to 925 MHz.)
OUTN
OUTP
GND
ADRF6655
T3
900MHz OUTPUT INT ERFACE
+VCC
1pF
GJM
68nH
0402CS
5.1nH
0402CS
47nH
0603CS
5.1nH
0402CS
+VCC
47nH
0603CS
TC1-1-13M+
1nF
150pF
1nF IF O UT
150pF
18 19 20
08817-056
Figure 54. 900 MHz Output Matching Network Using the TC1-1-13M+ 1:1
Impedance Ratio Balun and External Pull-Up Choke Inductors (Output return
loss measured to be better than 12 dB from 815 MHz to 1075 MHz.)
OUTN
OUTP
GND
A
DRF6655
T3
1200MHz OUTP UT I NTERFACE
+VCC
1.8pF
GJM
17nH
0302CS
2.1nH
0302CS
47nH
0603CS
2.1nH
+VCC
47nH
0603CS
TC1-1-13M+ IF OUT
1nF
150pF
1nF
150pF
18 19 20
0
8817-057
Figure 55. 1200 MHz Output Matching Network (Output return loss
measured to be better than 12 dB from 950 MHz to 1500 MHz.)
OUTN
OUTP
GND
DRF6655
T3
1300MHz OUTP UT I NTERF ACE
+VCC
1.2pF
GJM
10nH
0302CS
2.7nH
0402CS
47nH
0603CS
2.7nH
0402CS
+VCC
47nH
0603CS
TC1-1-13M+ IF OUT
1nF
150pF
1nF
150pF
18 19 20
08817-058
Figure 56. 1300 MHz Output Matching Network (Output return loss
measured to be better than 12 dB from 1075 MHz to 1525 MHz.)
ADRF6655
Rev. 0 | Page 20 of 44
OUTN
OUTP
GND
ADRF6655
T6
1600MHz OUT PUT I NTERF ACE
VCC
1.5pF
15nH
0
36nH
VCC
36nH
IF OUT
1nF
150pF
1nF
150pF
1nF
0
ANAREN
BD1722J50200A00
18 19 20
0
8817-059
Figure 57. 1600 MHz Output Matching Network (Output return loss
measured to be better than 12 dB from 1400 MHz to 1680 MHz.)
OUTN
OUTP
GND
ADRF6655
T3
2100MHz OUTP UT I NTERF ACE
VCC
VCC
27nH
0603CS
27nH
0603CS IF OUT
1nF
150pF
3pF
3pF 1nF
150pF
TC1-1-13M+
18 19 20
08817-060
Figure 58. 2100 MHz Output Matching Network (Output return loss
measured to be better than 12 dB from 2000 MHz to 2200 MHz.)
0
5
10
15
20
25
30
35
0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9
OUTPUT F REQUE NCY ( GHz)
OUTPUT IP3 AND OUTP UT P1d B (dBm)
900MHz MATCH
1200MHz M ATCH
1600MHz M ATCH OUTPUT P1dB
OUTPUT IP3
08817-061
Figure 59. Measured Output Linearity for 900 MHz, 1200 MHz, and 1600 MHz
Matching Networks (See Figure 54, Figure 55, and Figure 57 for Implementation)
0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9
OUT P UT FRE QUENCY ( GHz)
–10
–9
–8
–7
–6
–5
–4
–3
–2
–1
0
1
2
GAIN (dB)
900MHz M AT CH
1200MHz M ATCH
1600MHz M ATCH
08817-062
Figure 60. Measured Conversion Gain for 900 MHz, 1200 MHz, and 1600 MHz
Matching Networks (See Figure 54, Figure 55, and Figure 57 for Implementation)
INPUT MATCHING
The ADRF6655 uses a balanced 50 Ω input impedance to help
simplify external connections. For low loss interfacing, the driving
source should be transformed to present a balanced 50 Ω source
impedance. An appropriate 1:1 impedance ratio input balun should
be used when attempting to interface to an unbalanced 50 Ω
source. For input frequencies below ~1.5 GHz, the TC1-1-13M+
from Mini-Circuits or similar baluns should provide good return
loss and maximum power gain. For higher frequencies, baluns,
such as the TC1-1-43A+, are recommended for lowest insertion
loss. The ac coupling capacitors can be optimized with the balun to
provide optimum input match. A few examples are provided in
Figure 61 for a range of different IF output frequencies.
–35
–30
–25
–20
–15
–10
–5
0
0.5 1.0 1.5 2.0 2.5 3.0
FREQ UE NC Y (G Hz)
S11 (dB)
TC1-1- 4 3 A+ WI TH 10 pF AC COUP LING
TC1-1- 43A+ WI T H 3pF AC COUPLING
TC1- 1-43A+ W IT H 1.8p F AC COUP LI NG
08817-063
Figure 61. Measured RF Input Return Loss Using the TC1-1-43A+ 1:1 Balun
(Plotted for Several AC Coupling Capacitor Values)
It is also possible to use lumped element LC lattice networks to
transform an unbalanced source into a balanced source at the
mixer input pins. In either case, the mixer input pins should be
dc blocked using adequately sized series capacitors.
ADRF6655
Rev. 0 | Page 21 of 44
IP3SET LINEARIZATION FEATURE
The IP3SET pin (Pin 29) controls the overall current consumption
of the mixer core depending on the applied voltage. If left open,
the voltage on the IP3SET pin is ~2.3 V, and a typical input IP3 of
~25 dBm or higher can be expected across the operating frequency
range. As the IP3SET voltage is increased, the overall supply
current increases and the input IP3 can be improved from ~3 dB to
6 dB. For upconversion applications, an IP3SET voltage of ~3.2 V to
3.3 V results in very high output IP3 performance in excess of
30 dBm. Using an external resistor divider network connected
between VCC and GND, the IP3SET voltage can be derived.
Alternatively, the on-board 3.3 V LDO output (Pin 2) can be
used to derive the applied IP3SET voltage. However, it is
advisable to use good bypassing and a series inductor or ferrite
choke to ensure good high frequency isolation between Pin 1 and
Pin 29. If an auxiliary control DAC is available, the IP3SET pin can
be driven dynamically in applications where power levels are
changing over time, and it is desirable to conserve power at
lower input signal levels. Figure 62 and Figure 63 illustrate the
output linearity dependency on the IP3SET voltage. Note that
gain is independent of the IP3SET voltage.
20
21
22
23
24
25
26
27
28
29
30
31
32
33
2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7
IP3SET (V)
OUTPUT IP3 (dBm)
OUT PUT FREQUENCY = 1210M Hz
OUT PUT FREQUENCY = 1500M Hz
08817-111
Figure 62. Output IP3 vs. IP3SET Voltage for Output Frequency
OUT P UT FREQ UENCY (MHz)
GAIN (dB)
–10
–8
–6
–4
–2
0
2
4
6
8
10
12
14
16
18
20
2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7
OUTPUT FREQUENCY = 1210 MHz
OUTPUT FREQUENCY = 1500 MHz
OUTPUT P1dB
GAIN
08817-112
Figure 63. Output P1dB and Gain vs. IP3SET Voltage
CDAC LINEARIZATION FEATURE
In addition to the IP3SET broadband linearization solution, the
ADRF6655 also includes a special linearizer designed to provide
enhanced IP3 performance at higher input frequencies. At low
input frequencies, the CDAC setting offers very little influence
on input IP3, and a CDAC setting of 15 is usually recommended.
At high input frequencies, the CDAC setting can boost input
IP3 as much as 5 dB with essentially no increase in supplied
power. At a given input frequency, the ADRF6655 offers an
optimum CDAC setting to provide high input IP3 performance.
The recommended optimum CDAC setting vs. RF input frequency
is shown in Figure 64.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
1840 1940 2040 2140 2240 2340 2440
CDAC
RF FREQUENCY (MHz )
BEST CDAC AT 25° C
INTERCEPT
BEST CDAC AT 85° C
08817-066
Figure 64. Optimum CDAC Setting for Downconversion vs. RF Input Frequency
EXTERNAL LO INTERFACE
The ADRF6655 provides the option to use an external signal
source for the LO into the mixer. It is important to note that the
applied LO signal is divided by 2 or divided by 3 prior to the
actual mixer core within the ADRF6655. The divider is determined
by the register settings in LO path and mixer control register,
(see the Register 5—LO Path and Mixer Control section). The
LO input pins (Pin 37 and Pin 38) present a broadband balanced
50 Ω input interface similar to the input pins (Pin 25 and Pin 26).
The LOP and LON input pins should be dc blocked and driven
from a balanced 50 Ω source. When not in use, the LOP and
LON pins may be left unconnected.
ADRF6655
Rev. 0 | Page 22 of 44
ADRF6655
+5V
+5
V
EXT E RNAL VCO
VTUNE LI NE
NC
CHARGE PUM P
LOOP FILTER
EXTERNAL
REFERENCE
RSET
VCC1
DECL1
CP
GND
RSET
REFIN
GND
GND
GND
LON
LOP
VTUNE
DECL3
35
36
37
38
39
40
1
2
3
4
5
6
7
08817-067
USING AN EXTERNAL VCO
The ADRF6655 has the necessary provisions for interfacing an
external VCO. A high performance discrete VCO may be desirable
in applications that call for the very best phase noise performance.
The basic circuit connections for interfacing an external VCO
are included in Figure 65. It is important to select a VCO with a
frequency tuning voltage range that covers the available charge
pump output compliance range of 1 V to 2.8 V. The external VCO
waveform needs to pass through the on-chip divide-by-2/divide-
by-3 programmable dividers before reaching the mixer. As a result,
the VCO center frequency should be selected to be roughly 2×
or 3× the desired LO signal frequency. The available output power
for the selected VCO should be greater than −10 dBm to ensure
adequate signal levels into the mixer core. The charge pump loop
filter components should be designed to provide adequate phase
margin for the given KVCO tuning sensitivity of the selected VCO.
It is important to properly configure the digital registers for
external VCO operation. When using an external VCO, the
internal VCO should be disabled using DB17 in Register 6.
Other register programmable LDOs, including the VCO LDO
(DB18 in Register 6), should be enabled. For more information
on programming the ADRF6655, see the ADRF6655 Control
Software section.
Figure 65. External VCO Connections
ADRF6655
Rev. 0 | Page 23 of 44
ADRF6655 CONTROL SOFTWARE
The ADRF6655 can be controlled from most PCs that include
a parallel port output interface. A USB adapter board is also
available from Analog Devices, Inc., to allow for control from
PCs that do not have an accessible parallel port. The USB adapter
evaluation documentation and ordering information can be found
at www.analog.com by searching for EVAL-ADF4XXXZ-USB. The
basic user interfaces are depicted in Figure 66 and Figure 67.
After launching the software, the user is prompted to select a device
from the ADRF product family. Upon selecting the ADRF6655,
the main control interface should appear as shown in Figure 66.
The main control interface allows the user to configure the device
for various modes of operation. The internal synthesizer is
controlled by clicking on any of the numeric values listed in the
RF Section. Attempting to program the REF Input Frequency,
the PFD Frequency, the VCO Frequency [2×LO], or other
values in the RF section launches the Synthesizer Settings—
ADRF6655 Broadband Mixer control module depicted in
Figure 67. From the Synthesizer Settings control interface, the
user can enter the desired Local Oscillator Frequency (MHz),
Channel Step Resolution (kHz), and External Reference
Frequency (MHz). The user can also enable the LO output buffer
and divider options from this menu. After setting the desired
values, it is important to click Upload All Registers and
Windows for the new settings to take effect.
08817-069
Figure 66. ADRF6655 Software Control Interface
08817-070
Figure 67. ADRF6655 Synthesizer Settings User Interface
PLL LOOP FILTER DESIGN
Designing the external loop filter, which connects between the
charge pump output and VCO tuning control pin, is easy with
the help of ADIsimPLL. ADIsimPLL is a free software application
available from Analog Devices for designing PLL loop filters.
Several passive filter topologies are support in ADIsimPLL
along with the necessary component placements on the
evaluation board.
When designing a PLL loop filter, it is important to consider
settling time and phase noise requirements. Figure 68 provides
measured phase noise performance for a typical fast and slow
loop filter design. Note that the wider loop filter offers better
close-in phase noise but degraded phase noise at greater offset
frequencies. The narrow 1.5 kHz loop filter design provides the
best phase noise at 100 kHz and 1 MHz carrier offsets but with
the penalty of decreased frequency settling time and poorer
close-in performance.
–180
–160
–140
–120
–100
–80
–60
–40
–20
0
1k 10k 100k 1M 10M 100M
OFFSET FREQUENCY (Hz)
PHASE NOISE (dBc/Hz)
ADRF6655 1.5kHz L OOP F IL TER
67kHz L O O P F I LT ER
LO = 1100Hz
LO = 2275M Hz
08817-071
Figure 68. Phase Noise with Different Loop Filters
ADRF6655
Rev. 0 | Page 24 of 44
REGISTER STRUCTURE
DIVIDE
MODE
DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
0000000000000DMID6ID5ID4ID3ID2ID1ID0C3(0)C2(0)C1(0)
INT E GER DI V IDE RAT IO CONT ROL BITS
RESERVED
INTEGER DIVIDE CONTROL REGISTER (R0)
MODULUS DIVIDE CONTROL REGISTER (R1)
MODULUS DI V IDE VAL UE
DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
0 0 0 0 0 0 0 0 0 0 MD10 MD9 MD8 MD7 MD6 MD5 MD4 MD3 MD2 MD1 MD0 C3(0) C2(0) C1(1)
CONT ROL BITSRESERVED
FRACTIONAL DIVIDE CONTROL REGISTER (R2)
FRACT I O NAL DI VI DE VAL UE
DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
0 0 0 0 0 0 0 0 0 0 PD10 PD9 PD8 PD7 PD6 PD5 PD4 PD3 PD2 PD1 PD0 C3(0) C2(1) C1(0)
CONT ROL BITSRESERVED
Σ-Δ MODULATOR DITHER CONTROL REGISTER (R3)
DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
0 DITH1 DITH0 DEN C3(0) C2(1) C1(1)
CONT ROL BITS
DITHER
ENABLE
DV16 DV15 DV14 DV13 DV12 DV11 DV10 DV9 DV8 DV7 DV6 DV5 DV4 DV3 DV2 DV1 DV0
DITHER
MAGNITUDE DITHE R RE S TART V ALUE
DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
0 XVCO 0 0C3(1) C2(1) C1(1)
CONT ROL BITS
00000000000000000
EXTERNAL
VCO
ENABLE RESERVED
CHARGE PUMP, PFD, AND REFERENCE PATH CONTROL REGISTER (R4 )
CP
REF
PDF
PHASE
OFFSET
POLARITY
CP
CNTL
SRC
DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
RMS2 RMS1 RMS0 RS1 RS0 CPM CPBD CPB4 CPB3 CPB2 CPB1 CPB0 CPP1 CPP0 CPS CPC1 CPC0 PE1 PE0 PAB1 PAB0 C3(1) C2(0) C1(0)
OUPUT MUX
SOURCE INPUT REF
PATH
SOURCE PFD PHASE OFFSET
MULTIPLIER VALUE CP
CURRENT
MULTIPLIER
CHARGE
PUMP
CONTROL PFD EDGE
SENSITIVITY CO NTROL BITS
PFD ANTI-
BACKLASH
DELAY
LO PATH AND MIXER CONTROL REGISTER (R5)
RESERVED MIXER
BIAS
ENABLE PLL
ENABLE LO
DIV 2/ 3 LO
IN/OUT
CNTRL
LO OUTPUT
DRIVER
ENABLE
DB23DB22DB21DB20DB19DB18DB17DB16DB15DB14DB13DB12 DB7
MBE DB6 DB5 DB4 DB3DB11
CDAC3
DB10
CDAC2
DB9
CDAC1
DB8
CDAC0
PLEN LDIV LXL LDRV
CDAC DISTORTION
COMPENSATION
SETTING CONTROL BITS
00000000000 0
VCO CONTROL AND PLL ENABL ES REGISTER (R6)
DB2 DB1 DB0
C3(1) C2(0) C1(1)
CONTROL BIT S
DB2 DB1 DB0
C3(1) C2(1) C1(0)
CHARGE
PUMP
ENABLE
LDO
3.3V
ENABLE VCO
ENABLE VCO
SWITCH
CONTROL
VCO
BS
SRC
VCO
LDO
ENABLE V CO AMPLI TUDE SE T TI NGRESERVED VCO BAND S E LECT
DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3
DB23 CPEN L3EN VCOEN VCOSW VC5 VC4 VC3 VC2 VC1 VC0 VBSRC VBS5 VBS4 VBS3 VBS2 VBS1 VBS0
LVEN000
EXTERNAL VCO CONTROL REGISTER (R7)
RES
08817-068
Figure 69. Register Maps for ADRF6655 (The three control bits determine which register is programmed.)
ADRF6655
Rev. 0 | Page 25 of 44
DEVICE PROGRAMMING
The device is programmed through a 3-pin SPI port. The timing
requirements for the SPI port are described in Figure 2. There
are eight programmable registers, each with 24 bits, controlling
the operation of the device. The register functions can be broken
down as follows:
Register 0—integer divide control
Register 1—modulus divide control
Register 2—fractional divide control
Register 3—Σ-Δ modulator dither control
Register 4—charge pump, PFD, and reference path control
Register 5—LO path and mixer control
Register 6—VCO controls and PLL enables
Register 7—external VCO control
Note that the PLL has internal calibration that must run
whenever the device is programmed with a given frequency.
This calibration is automatically run whenever Register 0,
Register 1, or Register 2 is programmed. Software is available
from Analog Devices that allows easy programming from an
external PC. See the ADRF6655 Control Software section for
additional details.
INITIALIZATION SEQUENCE
To ensure proper power-up of the ADRF6655, it is important to
reset the PLL circuitry after the supply rail (VCC1, VCC2, VCCLO,
VCCV2I, and VCCMIX) has settled to 5 V ± 0.25 V. Resetting
the PLL ensures that the internal bias cells are properly configured
even under poor supply start-up conditions. To ensure that the
PLL is reset after power-up, the PLEN data bit (DB6) in Register
5 should be programmed to disable the PLL (PLEN = 0). After a
delay of >100 ms, Register 5 should be programmed to enable
the PLL (PLEN = 1). After this procedure, the registers should
be programmed as follows:
1. Register 7
2. Register 6
3. Register 4
4. Register 3
5. Register 2
6. Register 1
7. Delay >1 ms
8. Register 0
When programming the frequency of the ADRF6655, normally
only Register 2, Register 1, and Register 0 are programmed. When
programming these registers, a short delay of >500 μs should be
placed before programming the last register in the sequence
(Register 0). This ensures that the VCO band calibration initiated
by the first two register writes has sufficient time to complete
before the final band calibration (for Register 0) is initiated.
ADRF6655
Rev. 0 | Page 26 of 44
Divide Mode
REGISTER 0—INTEGER DIVIDE CONTROL
Divide mode determines whether fractional mode or integer
mode is used. In integer mode, the RF VCO output frequency
(fVCO) is calculated by
With R0[2:0] set to 000, the on-chip integer divide control register
is programmed as shown in Figure 70.
Integer Divide Ratio
fVCO = 2 × fPFD × (INT) (2)
The integer divide ratio is used to set the INT value in Equation 1.
The INT, FRAC, and MOD values make it possible to generate
output frequencies that are spaced by fractions of the PFD
frequency. The VCO frequency (FVCO) equation is
where INT is the integer divide ratio value (21 to 123 in integer
mode).
fVCO = 2 × fPFD × (INT + (FRAC/MOD)) (1)
where:
fVCO is the output frequency of the internal VCO.
fPFD is the frequency of operation of the phase-frequency
detector.
INT is the preset integer divide ratio value (24 to 119 in
fractional mode).
MOD is the preset fractional modulus (1 to 2047).
FRAC is the preset fractional divider ratio value (0 to MOD − 1).
DIVIDE
MODE
DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
0000000000000DMID6ID5ID4ID3ID2ID1ID0C3(0)C2(0)C1(0)
DM
0
1
ID6 ID5 ID4 ID3 ID2 ID1 ID0
0010101
0010110
0010111
0011000
... ... ... ... ... ... ...
... ... ... ... ... ... ...
0111000
... ... ... ... ... ... ...
... ... ... ... ... ... ...
1110111
1111000
1111001
1111010
1111011
...
...
119
120 (I NTEG ER MO DE ONLY)
INTEGER DIVIDE RATIO
21 (I NTEG E R MODE ONLY )
22 (I NTEG E R MODE ONLY )
23 (I NTEG E R MODE ONLY )
24
...
...
56
INTEGER
INT E GER DI V IDE RAT IO CONT ROL BITS
DIVIDE MODE
FRACTIONAL
121 (I NTEG ER MO DE ONLY)
122 (I NTEG ER MO DE ONLY)
123 (I NTEG ER MO DE ONLY)
RESERVED
08817-072
Figure 70. Integer Divide Control Register (R0)
ADRF6655
Rev. 0 | Page 27 of 44
REGISTER 1—MODULUS DIVIDE CONTROL
With R1[2:0] set to 001, the on-chip modulus divide control
register is programmed as shown in Figure 71.
The MOD value is the preset fractional modulus ranging from
1 to 2047.
REGISTER 2—FRACTIONAL DIVIDE CONTROL
With R2[2:0] set to 010, the on-chip fractional divide control
register is programmed as shown in Figure 72.
The FRAC value is the preset fractional modulus ranging from
0 to MOD − 1.
MODUL US DI V I DE RATIO
DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
0 0 0 0 0 0 0 0 0 0 MD10 MD9 MD8 MD7 MD6 MD5 MD4 MD3 MD2 MD1 MD0 C3(0) C2(0) C1(1)
MD10 MD9 MD8 MD7 MD6 MD5 MD4 MD3 MD2 MD1 MD0
0 0000000001
0 0000000010
... ... ... ... ... ... ... ... ... ... ...
... ... ... ... ... ... ... ... ... ... ...
0 0001100000
... ... ... ... ... ... ... ... ... ... ...
... ... ... ... ... ... ... ... ... ... ...
1 1111111111
MODULUS VALUE
...
...
2047
CONT ROL BITS
1
1536
2
...
...
RESERVED
08817-073
Figure 71. Modulus Divide Control Register (R1)
FD10FD9FD8FD7FD6FD5FD4FD3FD2FD1FD0
0 0000000000
0 0000000001
... ... ... ... ... ... ... ... ... ... ...
... ... ... ... ... ... ... ... ... ... ...
0 1100000000
... ... ... ... ... ... ... ... ... ... ...
... ... ... ... ... ... ... ... ... ... ...
FRACTIONAL VALUE MUST BE LE S S THAN MODUL US
FRACTIO NAL V AL UE
0
1
...
...
768
...
...
<MDR
FRACT IONAL DIVIDE V ALUERESERVED
DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
CON TRO L BITS
0000000000FD10FD9FD8FD7FD6FD5FD4FD3FD2FD1FD0C3(0)C2(1)C1(0)
08817-074
Figure 72. Fractional Divide Control Register (R2)
ADRF6655
Rev. 0 | Page 28 of 44
REGISTER 3—Σ-Δ MODULATOR DITHER CONTROL
With R3[2:0] set to 011, the on-chip, Σ-Δ modulator, dither
control register is programmed as shown in Figure 73.
The dither restart value can be programmed from 0 to 217 − 1,
though a value of 1 is typically recommended.
DITHER
ENABLE
DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
0 DITH1 DITH0 DEN DV16 DV15 DV14 DV13 DV12 DV11 DV10 DV9 DV8 DV7 DV6 DV5 DV4 DV3 DV2 DV1 DV0 C3(0) C2(1) C1(1)
DITH1 DITH0
00
01
10
11
DEN
0
1
DITHER
MAGNITUDE DITHER RES TART V ALUE CONT ROL BITS
DIT HER MAG NI T UDE
15
7
3
1 (RECO M M E NDE D)
DIT HE R ENABLE
DISABLE (RECOMM ENDE D)
ENABLE
DV16 DV15 DV14 DV13 DV12 DV11 DV10 DV9 DV8 DV7 DV6 DV5 DV4 DV3 DV2 DV1 DV0
00000000000000001
... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...
... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...
11111111111111111
0x00001
...
...
0x1FFFF
DITHER RESTART
VALUE
08817-075
Figure 73. Σ-Δ Modulator Dither Control Register (R3)
ADRF6655
Rev. 0 | Page 29 of 44
REGISTER 4—CHARGE PUMP, PFD, AND
REFERENCE PATH CONTROL
With R4[2:0] set to 100, the on-chip charge pump, PFD, and
reference path control register is programmed as shown in
Figure 74.
The charge pump current is controlled by the base charge
pump current (ICP, BASE) and the value of the charge pump
current multiplier (ICP, MULT).
The base charge pump current can be set using an internal or
external resistor (according to DB18 of Register 4). When using an
external resistor, the value of ICP, BASE can be varied according to
[]
8.37
250
4.217 ,
×
=Ω BASECP
I
RSET (3)
When using the internal resistor, the base charge pump current
is 250 μA. The actual charge pump current can be programmed
to be a multiple (1, 2, 3, or 4) of the charge pump base current.
The multiplying value (ICP, MULT) is equal to 1 plus the value of
Bit DB11 and Bit DB10 in Register 4.
The PFD phase offset multiplier (θPFD, OFS), which is set by Bit DB16
to Bit DB12 of Register 4, causes the PLL to lock with a nominally
fixed phase offset between the PFD reference signal and the
divided-down VCO signal. This phase offset is used to linearize
the PFD-to-CP transfer function and can improve fractional
spurs. The magnitude of the phase offset is determined by
MULTCP
OFSPFD
I,
,
5.22[deg]
θ
=ΔΦ
Finally, the phase offset can be either positive or negative
depending on the value of DB17 in Register 4.
The reference frequency applied to the PFD can be manipulated
using the internal reference path source. The external reference
frequency applied can be internally scaled in frequency by 2×, 1×,
0.5×, or 0.25×. This allows a broader range of reference frequency
selections while keeping the reference frequency applied to the
PFD within an acceptable range.
The ADRF6655 also provides a MUXOUT pin that can be
programmed to output a selection of several internal signals.
The default mode is to provide a lock-detect output to allow the
user to verify when the PLL has locked to the target frequency.
In addition, several other internal signals may be passed to the
MUXOUT pin, as described in Figure 74.
ADRF6655
Rev. 0 | Page 30 of 44
CP
REF
PDF
PHASE
OFFSET
POLARITY
CP
CNTL
SRC
DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
RMS2 RMS1 RMS0 RS1 RS0 CPM CPBD CPB4 CPB3 CPB2 CPB1 CPB0 CPP1 CPP0 CPS CPC1 CPC0 PE1 PE0 PAB1 PAB0 C3(1) C2(0) C1(0)
CPC1 CPC0
00
01
10
11
CPS
0
1
CPP1 CPP0
00
01
10
11
CPB4 CPB3 CPB2 CPB1 CPB0
00000
00001
00100
01010
... ... ... ... ...
11111
CPBD
0
1
CPM
0
1
RS1 RS0
00
01
10
11
RMS2 RMS1 RMS0
000
001
010
011
100
101
110
111
10 × 22.5°/ I
CP, M ULT
...
31 × 22.5°/ I
CP, M ULT
PFD P HAS E OF F S E T MULTIPL IER
0 × 22. 5 °/ I
CP, MULT
1 × 22. 5 °/ I
CP, MULT
4 × 22. 5 °/ I
CP, MULT
(RECO M M E NDE D)
BOT H ON
PUMP DOW N
PUMP UP
TRISTATE
OUPUT MUX
SOURCE INPUT REF
PATH
SOURCE PF D PHASE OFFSET
MULTIPLIER VALUE CP
CURRENT
MULTIPLIER
CHARGE
PUMP
CONTROL PFD EDGE
SENSITIVITY CO NTROL BITS
PFD ANTI-
BACKLASH
DELAY
PE0
0
1
REFE RENCE P AT H EDG E
SENSITIVITY
FALLING EDGE
RISING EDGE
PAB1 PAB0
00
01
10
11
PFD ANTI -BACKLASH
DELAY
0ns
0.5ns
0.75ns
0.9ns
CHARGE P UMP
CONTROL
0.5 × REFI N ( BUFF E RED)
CHARGE PUM P CONTROL S OURCE
CONT ROL BAS E D ON STATE OF DB7/DB8 (CP CONT ROL)
CO NTROL FR OM PFD
OUTPUT MUX SELECT
LO CK DE TECT
VPTAT
REFIN (BUF FERED)
PFD PHAS E O F F S ET PO LARI T Y
NEGATIVE
POSITIVE
CHARGE P UM P CURRENT
REFE RE NCE S OURCE
INTERNAL
EXTERNAL
0.25 × REFI N
CHARGE P UM P
CURRENT M ULTIPL IER
1
2
3
4
INPUT REF ERENCE
PATH SOURCE
2 × REFI N
REFIN
0.5 × RE FI N
2 × REF IN (BUFFE RE D)
TRISTATE
RESERVED (DO NOT USE)
RESERVED (DO NOT USE)
PE1
0
1
DIVIDER PATH EDGE
SENSITIVITY
FALLING EDGE (RECOMMENDED)
RISING EDGE
... ... ... ... ... ...
... ... ... ... ... ...
08817-076
Figure 74. Charge Pump, PFD, and Reference Path Control Register (R4)
ADRF6655
Rev. 0 | Page 31 of 44
REGISTER 5—LO PATH AND MIXER CONTROL
With R5[2:0] set to 101, the LO path and mixer control register
is programmed as shown in Figure 75.
The LO output driver can be enabled to allow the user to review
the performance of the internally applied LO through the LOP
and LON local oscillator input/output pins. The LO input/output
control allows the user to disconnect the internal LO signal and
apply an external LO signal to the LOP and LON local oscillator
input/output pins. A divide-by-2 or divide-by-3 prescaler can be
selected to divide the frequency of the externally or internally
applied oscillator signal before the mixer.
When using an external frequency, stable local oscillator signal
to commutate the mixer core, it is possible to shut down the PLL
circuitry through the PLL enable address (DB6) of Register 5.
The internal mixer can be disabled using the mixer bias enable
address (DB7) of Register 5.
Register 5 also provides access to the CDAC Distortion
Compensation Setting (DB11:DB8). CDAC control can allow
the user to optimize the internal linearization circuitry to enhance
IP3 performance for high frequency RF input signals.
CDAC3 CDAC2 CDAC1 CDAC0
0000
0001 MINIMUM
...
... ... ... ...
... ... ... ... ...
...
1111 MAXIMUM
CDAC DIST ORT ION
COMPENSATION
SETTLING
LDRV
0
1
LO OUTPUT DRIVER
ENABLE
DRIVE R OFF (RE COMME NDED)
DRIVE R ON
LXL
0
1
LO IN/OUT CONTROL
LO OUTPUT
LO INPUT
LDIV
0
1DIVIDE BY 3
DIVIDE BY 2
DIVIDE-BY - 2 O R DIV I DE -BY -3
PLEN
0
1DISABLE
ENABLE
PLL ENABL E
MBE
0
1DISABLE
ENABLE
MI XE R BIAS ENABLE
RESERVED MIXER
BIAS
ENABLE PLL
ENABLE LO
DIV 2/ 3 LO
IN/OUT
CNTRL
LO OUTPUT
DRIVER
ENABLE
DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB7
MBE DB6 DB5 DB4 DB3DB11
CDAC3
DB10
CDAC2
DB9
CDAC1
DB8
CDAC0
PLEN LDIV LXL LDRV
CDAC DISTORTION
COMPENSATION
SETTING CONT ROL BITS
00000000000 0 DB2 DB1 DB0
C3(1) C2(0) C1(1)
08817-077
Figure 75. LO Path and Mixer Control Register (R5)
ADRF6655
Rev. 0 | Page 32 of 44
REGISTER 6—VCO CONTROL AND PLL ENABLES
With R6[2:0] set to 110, the VCO control and PLL enables
register is programmed as shown in Figure 76.
The VCO tuning band is normally selected automatically by the
band calibration algorithm, although the user can directly select
the VCO band using Register 6.
The VCO BS SRC bit (DB9) determines whether the result of
the calibration algorithm is used to select the VCO band, or if
the band selected is based on the value in VCO band select
(DB8 to DB3).
The VCO amplitude can be controlled through Register 6. The
VCO amplitude setting can be controlled between 0 and 63.
The internal VCO can be disabled using Register 6. The internal
VCO LDO can be disabled if an external clean 2.9 V supply is
available to be applied to Pin 40. Additionally, the 3.3 V on-board
LDO can be disabled through Register 6 and an external 3.3 V
supply can be applied to Pin 2.
The internal charge pump can be disabled through Register 6.
Normally, the charge pump is enabled.
CHARGE
PUMP
ENABLE
LDO
3.3V
ENABLE VCO
ENABLE VCO
SWITCH
CONTROL
VCO
BS
SRC
VBSRC
0
1
VCOEN
VCO
LDO
ENABLE VCO AMPLITUDE SETTINGRESERVED VCO BAND SELECT
CHARGE PUM P E NABLE
VCO BAND CAL IBRAT ION
AND SW S OURCE CONTRO L
BAND CALI BRAT IO N
VCOSW
0
1
VCO SWI TCH CO NT ROL FROM S P I
REGULAR
BAND CALIBRAT I O N
SPI
VCO E NABL E
DISABLE
ENABLE
DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
CO NT R O L BIT S
DB23 CPEN L3EN VCOEN VCOSW VC5 VC4 VC3 VC2 VC1 VC0 VBSRC VBS5 VBS4 VBS3 VBS2 VBS1 VBS0 C3(1) C2(1) C1(0)
LVEN
0
1
LVEN VCO LDO E NABLE
DISABLE
ENABLE
0
1
L3EN LDO 3. 3V ENABLE
DISABLE
ENABLE
0
1
CPEN
DISABLE
ENABLE
0
1
000
0
24
...
...
VC3
0
1
...
...
1
VC2
0
0
...
...
1
VC4
0
1
...
...
0
VC5
0
0
...
...
1
VC1
0
0
...
...
1
VC0
0
0
47 (RECOMM ENDED)
111011
...
...
... ......... ... ...
...
163
VCO AM PLI TUDE
SETTING
0
32
...
VBS3
0
0
...
VBS2
0
0
...
VBS4
0
0
...
VBS5
0
1
...
VBS1
0
0
...
VBS0
0
0
63
111111
...
...
... ......... ... ...
VCO BAND
SELECT
FROM SPI
08817-078
Figure 76. VCO Control and Enables Register (R6)
ADRF6655
Rev. 0 | Page 33 of 44
REGISTER 7—EXTERNAL VCO CONTROL
With R6[2:0] set to 111, the external VCO control register is
programmed as shown in Figure 77.
The external VCO enable bit allows the use of an external VCO in
the PLL instead of the internal VCO. This can be advantageous in
cases where the internal VCO is not capable of providing the desired
frequency, or where the internal phase noise of the VCO is higher
than desired. By setting the external VCO enable bit (DB22) to 1,
and setting Bit DB15 to Bit DB10 of Register 6 to 0, the internal
VCO is disabled and the output of an external VCO can be fed into
the part differentially on Pin 38 and Pin 37 (LOP and LON).
Because the loop filter is already external, the output of the loop
filter simply needs to be connected to the external, tuning voltage
pin of the VCO. See the Using an External VCO section for more
information.
DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
0XVCO
EXTERNAL
VCO
ENABLE
RES
00 00000000000000000C3(1)C2(1)C1(1)
RESERVED CONTROL BITS
XVCO
0
1INT E RNAL VCO
EXT E RNAL VCO
EXT E RNAL VCO E NABLE
08817-079
Figure 77. External VCO Control Register (R7)
ADRF6655
Rev. 0 | Page 34 of 44
CHARACTERIZATION SETUPS
Figure 78 to Figure 80 show the general characterization bench
setups used extensively for the ADRF6655. The setup shown in
Figure 78 was used to do the bulk of the testing. An automated
Agilent VEE program was used to control the equipment over the
IEEE bus. This setup was used to measure gain, IP1dB, OP1dB,
IIP2, IIP3, OIP2, OIP3, LO-to-IF and LO-to-RF leakage, LO
amplitude, and supply current. The ADRF6655 was characterized
on an upconversion and downconversion evaluation board
configured for each conversion as described in the Input Matching
section and the Output Matching and Biasing section. For all
measurements of the ADRF6655, the loss of the RF input balun
was de-embedded.
To do phase noise and reference spurs measurements, see the
phase noise setup used in Figure 79. Phase noise measurements
were done on a downconversion board looking at the output at
different offsets.
Figure 80 shows the setup used to make the noise figure
measurements with no blocker present, and Figure 81 shows
the setup for making the noise figure measurements under
blocking conditions. Note that attention must be given to the
measurement setup. The RF blocker signal must be filtered
through a band-pass filter to prevent noise (which increases
when output power is increased) from contributing at the desired
RF frequency. At least 30 dB attenuation is needed at the desired
RF and image frequencies. For example, to generate a blocker
signal at the IF output of 205 MHz, the blocker signal generator
is set at 995 MHz, and the part is programmed to generate a LO
frequency of 1200 MHz that results in an output signal of 205 MHz.
This signal must be filtered out through a band reject filter on
the output so that the noise figure can be measured at 200 MHz,
which corresponds to the output frequency for LO = 1200 MHz
and RF input = 1000 MHz.
ADRF6655
Rev. 0 | Page 35 of 44
RHODE & SCHWARTZ SMT03
SIGNAL GENERATOR
AGILENT E3631A
POWER SUPPLY
AGILENT E4437 SIGNAL GENERATOR
AGILE NT PSG-A SIGNAL GE NERATO R
RHODE & SCHW ART Z F S EA30
MINI-CIRCUITS ZHL-42W
AMPLIFIER
(SUPP LI ED WI TH +15V DC F OR
OPERATION)
AGIL EN T 11636A
POWER DI V IDER
(USED AS
COMBINER)
REF, LO
RF
RF
3dB
RF SWITCH
MARTIX
2dB
ADRF6655
EVAL UATION BOARD
10dB 6dB6dB
IF
IF
AGILENT
34980A MUL TI FUNCTION
SWITCH
(W IT H 34950 AND
2× 34921 M ODULE S) 10-PIN
CONNECTION
(+5V VPOS,
DC MEASURE )
9-PI N D- S UB CONNECT IO N
(VCO AND PLL PROGRAM M ING)
RF
IEEE
IEEE
IEEE
IEEE
IEEE
IEEE
IEEE
IEEE
AGILENT 34401A DM M
(DC I M ODE, USED
FOR SUPP L Y CURRENT
MEASUREMENT)
IEEE
RF LO, REF
3dB
3dB
08817-116
Figure 78. General Characterization Setup
ADRF6655
Rev. 0 | Page 36 of 44
AGILENT E3631A
POW ER S UPPL Y
RF SWITCH
MATRIX
ADRF6655
EVAL UATION BOARD
IF
IF
AGILENT
34980A MULTIFUNCTI ON
SWITCH
(W I T H 34950 AND
2× 34921 M ODULE S ) 10-PIN
CONNECTION
(+5V VPOS,
DC MEASURE )
9-PI N D- S UB CONNECT ION
(VCO AND PLL P ROGRAM M ING)
IEEE
IEEE
IEEE
IEEE
IEEE
IEEE IEEE
AGILE NT 34401A DM M
(DC I MODE, USED
FOR SUPP L Y CURRENT
MEASUREMENT)
IEEE
RF LO, REF
AGI LE NT E5052 SIGNAL
SOURCE ANAL YZE R
RHODE & S CHW ARTZ
SMA100 S IGNAL
GENERATOR
RHODE & S CHWARTZ
SMA100 S IG N AL
GENERATOR
REFRF
AGILE NT E4 440A
SPECTRUM ANAL YZER
IEEE
08817-117
Figure 79. Phase Noise Setup
ADRF6655
Rev. 0 | Page 37 of 44
AGILE N T 8665B LOW
NOISE S IGNAL
GENERATOR
AGI L E NT 34401A DMM
(IN DC I MO DE FO R SUPPLY
CURRENT M EAS URE M E NT)
AGILE NT E 3631A P OW E R
SUPPLY
AGILENT N8974A NOISE
FIGURE ANALYZ E R
AGI LENT 346B NO ISE
SOURCE
10MHz
REFERENCE
IF OUT
REF IN
RF IN
AGILE N T 34980A
MULTIFUNCTION SWITCH
(W IT H 34950 AND 34921 M ODUL E S )
IEEE
IEEE
IEEE
IEEE
ADRF6655
EVAL UATION BOARD
6dB
6dB
IEEE
08817-118
Figure 80. Noise Figure Setup
ADRF6655
EVAL UATION BOARD
AGILENT 86 65B LOW
NOISE SIGNAL
GENERATOR
AG ILENT 34 6 B NOISE
SOURCE COMBINER RF IN
IF OUT
REF IN RHODE & SCHW ART Z
SMA100
SIG NAL G E NE RAT OR
AGILE NT N8974A
NOISE FIGURE
ANALYZER
08817-119
Figure 81. Noise Figure with Presence of Blocker Signal
ADRF6655
Rev. 0 | Page 38 of 44
EVALUATION BOARD LAYOUT AND THERMAL GROUNDING
An evaluation board is available for testing the ADRF6655. The standard evaluation is configured for downconversion applications. Table 5
provides the component values and suggestions for modifying component values for various modes of operation.
0
8817-125
40 39 38 37 36 35 34 33 32 31
11 12 13 14 15 16 17 18 19 20
1
2
3
4
5
6
7
8
9
10 21
22
23
24
25
26
27
28
29
30
NC
GND
NC
GND
LON
LOP
DECL3
VTUNE
GND
INP
GND
GND
VCCV2I
GND
GND
INN
VCCMIX
GND
IP3SET
OUTP
CLK
DATA
OUTN
VCCLO VCCLO
LE
GND
GND
GND
NC
VCC1
ADRF6655
V
CC 3P3V_LDO
CP
LO
VCC
VTUNE
VCC
VCC
IP3SET
VCC_RF
C5
1nF
C6
1nF
RF
VCC_BB
IFP
C14
0.1µF
C9
0.1µF
C11
0.1µF
C7
0.1µF
C15
4.7µF
C13
47nF
R10
68
R9
270
VCC
IFN
VCC
OUT
VCC
VCC_LO
REFIN
REFOUT
2.5V
VCC2
R58
OPEN
R47
0
L1
OPEN
L2
OPEN C36
OPEN
C35
OPEN
R44
OPEN
R43
0
R48
0
R25
0
R26
0
R24
0
R59
0
C29
0.1µF
0
T3, T6
T4, T 5
R27
OPEN
R60
OPEN
T7, T8
C10
100pF
C12
100pF
L3
OPEN
C8
100pF
R37
0
R38
0R65
0
R6
0
C40
OPEN
R12
OPEN
R5
OPEN
R2
OPEN
R63
0
R62
0
R1
0
R13
0
C1
100pF
C2
10µF
VCO_LDO
R72
0
C31
1nF
R16
0
R8
0
R7
0
C16
100pF
C17
0.1µF
C39
10µF
12345
6789
CLK
C32
330pF
C33
330pF
DATA
R52
1k
R50
1k
R51
1k
R35
100
R36
0
R3
10k
R17
0
R18
0
R30
100
C18
100pF
C34
330pF
R57
100
LE
VTUNE
VCC
C20
0.1µF
C23
0.1µF
C25
0.1µF
C27
0.1µF
C3
0.1µF
C21
100pF
C43
150pF
C42
150pF
R73, R74
C22
100pF
C24
100pF
C37
100pF
C38
100pF
VCC_RF VCC_BBVCC_LO
R32
0
R31
0
R29
0
C28
10µF
DECL1
CP
GND
RSET
REFIN
GND
MUXOUT
DECL2
VCC2
C19
0.1µF
R61
49.9
C41
10µF
Figure 82. Evaluation Board Schematic
ADRF6655
Rev. 0 | Page 39 of 44
The package for the ADRF6655 features an exposed paddle
on the underside that should be well soldered to a low thermal
and electrical impedance ground plane. This paddle is typically
soldered to an exposed opening in the solder mask on the
evaluation board. Figure 83 illustrates the dimensions used
in the layout of the ADRF6655 footprint on the ADRF6655
evaluation board (1 mil. = 0.0254 mm).
Notice the use of nine via holes on the exposed paddle. These
ground vias should be connected to all other ground layers on the
evaluation board to maximize heat dissipation from the device
package. Under these conditions, the thermal impedance of the
ADRF6655 was measured to be approximately 29°C/W in still air.
.168
.232
.177
.035
.050
.012
.025
.020
08817-085
Figure 83. Evaluation Board Layout Dimensions for the ADRF6655 Package
08817-083
Figure 84. Evaluation Board Top Layer
08817-084
Figure 85. Evaluation Board Bottom Layer
ADRF6655
Rev. 0 | Page 40 of 44
Table 5. Evaluation Board Configuration Options
Component Function Default Condition
VCC, GND, IP3SET, CP,
VCO_LDO, VCC_LO,
VCC_RF, VCC_BB, LE,
CLK, DATA
Power supply, ground, and other test points. Not applicable
R1, R6, R7, R8, R17,
R18, R24, R25, R26,
R29, R31, R32, R36
Power supply decoupling. Shorts or power supply decoupling resistors. R1, R6, R7, R8 = 0 Ω (0402),
R17, R18 = 0 Ω (0402),
R24, R25, R26 = 0 Ω (0402),
R29, R31, R32 = 0 Ω (0402),
R36 = 0 Ω (0402)
C1, C2, C7, C8, C9,
C10, C11, C12, C16,
C17, C18, C19, C20,
C21, C22, C23, C24,
C25, C27, C28, C29,
C39, C41, C42, C43
The capacitors provide the required decoupling of the supply-related pins. C1, C8, C10 = 100 pF (0402),
C2, C39, C41 = 10 μF (0603),
C7, C9, C11 = 0.1 μF (0402),
C12, C16, C18 = 100 pF (0402),
C21, C22, C24 = 100 pF (0402),
C17, C19, C20 = 0.1 μF (0402),
C23, C25, C27 = 0.1 μF (0402),
C28 = 10 μF (3216),
C29 = 0.1 μF (0402),
C42, C43 = 150 pF (0402)
C5, C6, T7, T8 External LO path. T7 and T8 provide different footprints for different LO
path transformer selections. C5 and C6 provide the necessary ac coupling.
C5, C6 = 1 nF (0402),
T7 = open (generic footprint),
T8 = TC1-1-13M+ (Mini-Circuits)
R61, C31, R16 REFIN input path. R61 provides a broadband 50 Ω termination followed
by C31, an ac coupling capacitor. R16 provides an external connectivity
to the MUXOUT feature described in Register 4.
R61 = 49.9 Ω (0402),
C31 = 1 nF (0402), R16 = 0 Ω (0402)
R2, R5, R9, R10, R13,
R37, R38, R62, R63,
R65, R72, C13, C14,
C15, C40
Loop Filter Component Options. A variety of loop filter topologies are
supported using component placements R9, R10, R13, R37, C13, C14,
C15, R65, and C40. R2 provides resistor programmability of the charge
pump current (see Register 4 description). R5, R38, R62, R63, and R72
provide connectivity options to numerous test points for engineering
evaluation purposes.
R2 = R5 = open, R9 = 270 Ω (0402),
R10 = 68 Ω (0402), R13 = 0 Ω (0402)
C13 = 47nF, C14 = 0.1μF,
C15 = 4.7μF (0805),
C40 = open (0402),
R37, R38, R62, R63, R65, R72 = 0 Ω (0402)
L1, L2, R43, R44,
R47, R48, R58, R59,
R73, R74, T3, T6,
C35, C36
IF output path. This is the default configuration of the evaluation board
for downconversion applications. R73 and R74 are populated for
appropriate balun interface. The default values support a TC4-1W+ 4-to-1
impedance ratio transformer with center tap bias connection through
R59. A differential IF output interface can be configured by populating C35
and C36 and omitting R47 and R48. When configuring for differential output
operation or when using an ac-coupled transformer, it is important to use L1
and L2 to provide dc bias to the IF output pins. For additional information,
see the Output Matching and Biasing section.
L1, L2 = open, R44, R58, = open,
R43, R47, R48 = 0 Ω (0402),
R59, R73, R74 = 0 Ω (0402),
T3 = TC4-1W+ (Mini-Circuits),
T6 = open, C35, C36 = open
C37, C38, T4, T5 RF input interface. T4 and T5 provide different footprints for different
RF path transformer selections. C37 and C38 provide the necessary ac
coupling. See the Input Matching section for additional information.
C37, C38 = 100 pF (0402),
T4 = TC1-1-13M+ (Mini-Circuits),
T5 = open
P1, R3, R30, R35,
R50, R51, R52,
R57, C32, C33, C34
Serial port interface. A 9-pin D-sub connector is provided for connecting to a
host PC or control hardware. RC filter networks are provided on CLK, DATA,
and LE lines to help clean up PC control signal wave shape. Test points are
provided for control interface debug. R3 provides a connection to the
MUXOUT for sensing lock detect through the P1 connector. See the Digital
Interfaces section for additional information.
P1 = 9-pin D-sub male,
R3 = 10 kΩ (0402),
R30, R35, R57 = 100 Ω (0402),
R50, R51, R52 = 1 kΩ (0402),
C32, C33, C34 = 330 pF (0402)
C3, R12, R27, R60, L3 IP3SET linearization feature. R27 and R60 provision for a resistive divider
network for providing nominal IP3SET voltage. Alternatively, the IP3SET
pin can be externally driven via the test point or directly connected to
the 3.3 V LDO (Pin 2, DECL1) using a 0 Ω resistor for R12 and a ferrite chip
inductor for L3. For additional information regarding this feature, see the
IP3SET Linearization Feature section.
C3 = 0.1 μF (0402), R12 = open,
R27, R60 = open, L3 = open
ADRF6655
Rev. 0 | Page 41 of 44
OUTLINE DIMENSIONS
1
40
10
11
31
30
21
20
4.25
4.10 SQ
3.95
TOP
VIEW
6.00
BSC SQ
PIN 1
INDICATOR 5.75
BSC SQ
12° MAX
0.30
0.23
0.18 0 .20 REF
SEATING
PLANE
1.00
0.85
0.80
0.05 M A X
0.02 NOM
COPLANARITY
0.08
0.80 M A X
0.65 TYP
4.50
REF
0.50
0.40
0.30
0.50
BSC
PIN 1
INDICATOR
0.60 M A X
0.60 M AX
0.25 M IN
EXPOSED
PAD
(BOTTOM VIEW)
COMP LIANT TO JEDE C STANDARDS MO - 220-VJJD-2
072108-A
FOR PROP ER CONNECTION O F
THE EXPOSED PAD, REFER TO
THE P IN CONFI GURATION AND
FUNCT ION DE S CRIPT IONS
SECT ION OF THIS DATA SHEE T.
Figure 86. 40-Lead Lead Frame Chip Scale Package [LFCSP_VQ]
6 mm × 6 mm Body, Very Thin Quad
(CP-40-1)
Dimensions shown in millimeters
ORDERING GUIDE
Model1 Temperature Package Description Package Option Quantity
ADRF6655ACPZ-R7 −40°C to +85°C 40-Lead Lead Frame Chip Scale Package [LFCSP_VQ] CP-40-1 750
ADRF6655-EVALZ Evaluation Board
1 Z = RoHS Compliant Part.
ADRF6655
Rev. 0 | Page 42 of 44
NOTES
ADRF6655
Rev. 0 | Page 43 of 44
NOTES
ADRF6655
Rev. 0 | Page 44 of 44
NOTES
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