34
750 MHz to 1150 MHz Quadrature Demodulator with Fractional-N PLL and VCO Data Sheet ADRF6801 Rev. A Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 ©2011–2018 Analog Devices, Inc. All rights reserved. Technical Support www.analog.com FEATURES IQ demodulator with integrated fractional-N PLL LO frequency range: 750 MHz to 1150 MHz Input P1dB: 12.5 dBm Input IP3: 25 dBm Noise figure (DSB): 14.3 dB Voltage conversion gain: 5.1 dB Quadrature demodulation accuracy Phase accuracy: 0.3° Amplitude accuracy: 0.05 dB Baseband demodulation: 275 MHz, 3 dB bandwidth SPI serial interface for PLL programming 40-lead, 6 mm × 6 mm LFCSP APPLICATIONS QAM/QPSK RF/IF demodulators Cellular W-CDMA/CDMA/CDMA2000 Microwave point-to-(multi)point radios Broadband wireless and WiMAX GENERAL DESCRIPTION The ADRF6801 is a high dynamic range IQ demodulator with integrated PLL and VCO. The fractional-N PLL/synthesizer generates a frequency in the range of 3.0 GHz to 4.6 GHz. A divide-by-4 quadrature divider divides the output frequency of the VCO down to the required local oscillator (LO) frequency to drive the mixers in quadrature. Additionally, an output buffer can be enabled that generates an fVCO/2 signal for external use. The PLL reference input is supported 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 IQ demodulator mixes the differential RF input with the complex LO derived from the quadrature divider. The differential I and Q output paths have excellent quadrature accuracy and can handle baseband signaling or complex IF up to 120 MHz. The ADRF6801 is fabricated using an advanced silicon-germanium BiCMOS process. It is available in a 40-lead, exposed-paddle, RoHS-compliant, 6 mm × 6 mm LFCSP package. Performance is specified over the −40°C to +85°C temperature range. FUNCTIONAL BLOCK DIAGRAM MUX RSET GND LON LOP MUX TEMP SENSOR GND VCCBB GND VCCLO BUFFER BUFFER QBBN VCCLO + CHARGE PUMP 250μA, 500μA (DEFAULT), 750μA, 1000μA PRESCALER ÷2 VCO LDO 2.5V LDO LE CLK SPI INTERFACE DATA MUXOUT REFIN ADRF6801 34 GND LOSEL 35 19 QBBP 18 17 16 DECL1 40 VTUNE 39 DECL2 VCC2 9 10 5 DECL3 2 VCC1 1 8 6 GND 7 14 GND 15 13 12 38 GND 11 37 36 GND 31 IBBN IBBP 32 33 28 VCCRF 27 RFIN 26 GNDRF 25 GND 24 GND 23 VCCBB 22 GND GND 21 20 29 30 PHASE FREQUENCY DETECTOR THIRD-ORDER FRACTIONAL INTERPOLATOR FRACTION REG MODULUS INTEGER REG N COUNTER GND 4 CPOUT 3 ×2 ÷2 ÷4 DIVIDER ÷1 OR ÷2 VCO CORE 09576-001 BUFFER CTRL QUAD ÷2 3.3V LDO Figure 1.

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Page 1: 750 MHz to 1150 MHz Quadrature Demodulator with Fractional ... · 750 MHz to 1150 MHz Quadrature Demodulator with Fractional-N PLL and VCO Data Sheet ADRF6801 Rev. A Document Feedback

750 MHz to 1150 MHz Quadrature Demodulator with Fractional-N PLL and VCO

Data Sheet ADRF6801

Rev. A Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 ©2011–2018 Analog Devices, Inc. All rights reserved. Technical Support www.analog.com

FEATURES IQ demodulator with integrated fractional-N PLL LO frequency range: 750 MHz to 1150 MHz Input P1dB: 12.5 dBm Input IP3: 25 dBm Noise figure (DSB): 14.3 dB Voltage conversion gain: 5.1 dB Quadrature demodulation accuracy

Phase accuracy: 0.3° Amplitude accuracy: 0.05 dB

Baseband demodulation: 275 MHz, 3 dB bandwidth SPI serial interface for PLL programming 40-lead, 6 mm × 6 mm LFCSP

APPLICATIONS QAM/QPSK RF/IF demodulators Cellular W-CDMA/CDMA/CDMA2000 Microwave point-to-(multi)point radios Broadband wireless and WiMAX

GENERAL DESCRIPTION The ADRF6801 is a high dynamic range IQ demodulator with integrated PLL and VCO. The fractional-N PLL/synthesizer generates a frequency in the range of 3.0 GHz to 4.6 GHz. A divide-by-4 quadrature divider divides the output frequency of the VCO down to the required local oscillator (LO) frequency to drive the mixers in quadrature. Additionally, an output buffer can be enabled that generates an fVCO/2 signal for external use.

The PLL reference input is supported 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 IQ demodulator mixes the differential RF input with the complex LO derived from the quadrature divider. The differential I and Q output paths have excellent quadrature accuracy and can handle baseband signaling or complex IF up to 120 MHz.

The ADRF6801 is fabricated using an advanced silicon-germanium BiCMOS process. It is available in a 40-lead, exposed-paddle, RoHS-compliant, 6 mm × 6 mm LFCSP package. Performance is specified over the −40°C to +85°C temperature range.

FUNCTIONAL BLOCK DIAGRAM

MUX

RSETGND

LON

LOP

MUX

TEMPSENSOR

GNDVCCBBGND

VCCLO

BUFFER

BUFFER

QBBN

VCCLO

–+ CHARGE PUMP

250µA,500µA (DEFAULT),750µA,1000µA

PRESCALER÷2

VCO LDO2.5V LDO

LECLK SPI

INTERFACE

DATA

MUXOUT

REFIN

ADRF680134

GND LOSEL35

19

QBBP18

17

16

DECL140

VTUNE39

DECL2VCC2910 5

DECL32

VCC11

8

6

GND 7

14

GND 15

13

12

38

GND 11

37

36GND

31IBBNIBBP

3233

28

VCCRF27

RFIN26

GNDRF25

GND24

GND23

VCCBB22

GND

GND

21

20

29

30

PHASEFREQUENCYDETECTOR

THIRD-ORDERFRACTIONAL

INTERPOLATOR

FRACTIONREG MODULUS INTEGER

REG

N COUNTER

GND4

CPOUT3

×2

÷2

÷4

DIVIDER÷1OR÷2

VCOCORE

0957

6-00

1

BUFFERCTRL

QUAD÷2

3.3V LDO

Figure 1.

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ADRF6801 Data Sheet

Rev. A | Page 2 of 34

TABLE OF CONTENTS Features .............................................................................................. 1 Applications ....................................................................................... 1 General Description ......................................................................... 1 Functional Block Diagram .............................................................. 1 Revision History ............................................................................... 2 Specifications ..................................................................................... 3

Timing Characteristics ................................................................ 5 Absolute Maximum Ratings ............................................................ 6 Pin Configuration and Function Descriptions ............................. 7 Typical Performance Characteristics ............................................. 9

Synthesizer/PLL .......................................................................... 12 Complementary Cumulative Distribution Functions (CCDF) ....................................................................................................... 13

Circuit Description ......................................................................... 14 LO Quadrature Drive ................................................................. 14 V-to-I Converter ......................................................................... 14 Mixers........................................................................................... 14 Emitter Follower Buffers ........................................................... 14 Bias Circuitry .............................................................................. 14

Register Structure ....................................................................... 14 Applications Information .............................................................. 21

Basic Connections ...................................................................... 21 Supply Connections ................................................................... 21 Synthesizer Connections ........................................................... 21 I/Q Output Connections ........................................................... 22 RF Input Connections ............................................................... 22 Charge Pump/VTUNE Connections ...................................... 22 LO Select Interface ..................................................................... 22 External LO Interface ................................................................ 22 Setting the Frequency of the PLL ............................................. 22 Register Programming ............................................................... 22 EVM Measurements .................................................................. 23

Evaluation Board Layout and Thermal Grounding ................... 24 ADRF6801 Software .................................................................. 28

Characterization Setups ................................................................. 30 Outline Dimensions ....................................................................... 34

Ordering Guide .......................................................................... 34

REVISION HISTORY 6/2018—Rev. 0 to Rev. A Change to Register Structure Section .......................................... 14 Changes to Register Programming Section ................................ 22 1/2011—Revision 0: Initial Version

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Data Sheet ADRF6801

Rev. A | Page 3 of 34

SPECIFICATIONS VS = 5 V; ambient temperature (TA) = 25°C; fREF = 26 MHz, fLO = 900 MHz, fBB = 4.5 MHz, RLOAD = 450 Ω differential, all register and PLL settings use the recommended values shown in the Register Structure section, unless otherwise noted.

Table 1. Parameter Test Conditions/Comments Min Typ Max Unit RF INPUT AT 900 MHz RFIN pins

Internal LO Frequency Range With VCO amplitude = 63 (R6 [DB15 to DB10]) 750 1125 MHz With VCO amplitude = 24 (R6 [DB15 to DB10]) 750 1150 MHz Input Return Loss Measured at 900 MHz <−20 dB Input P1dB 12.5 dBm Second-Order Input Intercept (IIP2) −5 dBm each tone >65 dBm Third-Order Input Intercept (IIP3) −5 dBm each tone 25 dBm Noise Figure Double sideband from RF to either I or Q output 14.3 dB With a −10 dBm interferer 5 MHz away 18.9 dB LO-to-RF Leakage At 1×LO frequency, 50 Ω termination at the RF port −75 dBm

I/Q BASEBAND OUTPUTS IBBP, IBBN, QBBP, QBBN pins Voltage Conversion Gain 450 Ω differential load across IBBP, IBBN (or QBBP, QBBN) 5.1 dB Demodulation Bandwidth 1 V p-p signal 3 dB bandwidth 275 MHz Quadrature Phase Error 0.3 Degrees I/Q Amplitude Imbalance 0.05 dB Output DC Offset (Differential) ±5 mV Output Common-Mode Voltage VPOS − 2.4 V Gain Flatness Any 5 MHz (<100 MHz) 0.2 dB p-p Maximum Output Swing Differential 450 Ω load 4 V p-p Differential 200 Ω load 2.4 V p-p Maximum Output Current Each pin 12 mA p-p

LO INPUT/OUTPUT LOP, LON Output Level Into a differential 50 Ω load, LO buffer enabled (LO

frequency = 900 MHz, output frequency = 1800 MHz) −2.5 dBm

Input Level Externally applied 2×LO, PLL disabled 0 dBm Input Impedance Externally applied 2×LO, PLL disabled 50 Ω VCO Operating Frequency With VCO amplitude = 63 (R6 [DB15 to DB10]) 3000 4500 MHz With VCO amplitude = 24 (R6 [DB15 to DB10]) 3000 4600 MHz

SYNTHESIZER SPECIFICATIONS All synthesizer specifications measured with recommended settings provided in Figure 33 through Figure 39

Channel Spacing fPFD = 26 MHz; modulus = 2047 25 kHz PLL Bandwidth Can be adjusted with off-chip loop filter component

values and RSET 130 kHz

SPURS fLO = 900 MHz, fREF = 26 MHz, fPFD = 26 MHz, measured at BB outputs with fBB = 50 MHz

Reference Spurs fREF = 26 MHz, fPFD = 26 MHz −91.6 dBc fPFD/2 −107.8 dBc fPFD × 2 −89.1 dBc fPFD × 3 −94.2 dBc

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ADRF6801 Data Sheet

Rev. A | Page 4 of 34

Parameter Test Conditions/Comments Min Typ Max Unit PHASE NOISE (USING 130 kHz LOOP FILTER) fLO = 900 MHz, fREF = 26 MHz, fPFD = 26 MHz, measured

at BB outputs with fBB = 50 MHz

1 kHz offset −99.5 dBc/Hz 10 kHz offset −107.8 dBc/Hz 100 kHz offset −106.6 dBc/Hz 500 kHz offset −126.7 dBc/Hz 1 MHz offset −131.7 dBc/Hz 5 MHz offset −143.5 dBc/Hz 10 MHz offset −150.5 dBc/Hz

Integrated Phase Noise 1 kHz to 10 MHz integration bandwidth 0.16 °rms PHASE NOISE (USING 2.5 kHz LOOP FILTER) fLO = 900 MHz, fREF = 26 MHz, fPFD = 26 MHz, measured

at BB outputs with fBB = 50 MHz

1 kHz offset −71.3 dBc/Hz 10 kHz offset −88.3 dBc/Hz 100 kHz offset −114.1 dBc/Hz 500 kHz offset −129.5 dBc/Hz 1 MHz offset −138.6 dBc/Hz 5 MHz offset −150.2 dBc/Hz 10 MHz offset −150.3 dBc/Hz PLL FIGURE OF MERIT (FOM) Measured with fREF = 26 MHz, fPFD = 26 MHz −215.4 dBc/Hz/Hz Measured with fREF = 104 MHz, fPFD = 26 MHz −220.9 dBc/Hz/Hz

Phase Detector Frequency 20 26 40 MHz REFERENCE CHARACTERISTICS REFIN, MUXOUT pins

REFIN Input Frequency Usable range 10 160 MHz REFIN Input Capacitance 4 pF MUXOUT Output Level VOL (lock detect output selected) 0.25 V VOH (lock detect output selected) 2.7 V REFOUT Duty Cycle 50 %

CHARGE PUMP Pump Current 500 µA Output Compliance Range 1 2.8 V

LOGIC INPUTS CLK, DATA, LE pins Input High Voltage, VINH 1.4 3.3 V Input Low Voltage, VINL 0 0.7 V Input Current, IINH/IINL 0.1 µA Input Capacitance, CIN 5 pF

POWER SUPPLIES VCC1, VCC2, VCCLO, VCCBB, VCCRF pins Voltage Range (5 V) 4.75 5 5.25 V Supply Current (5 V) Normal Rx mode, internal LO 262 mA Rx mode, internal LO with LO buffer enabled 288 mA Rx mode, using external LO input (internal VCO, PLL shut

down) 157 mA

Supply Current (5 V) Power-down mode 20 mA

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Data Sheet ADRF6801

Rev. A | Page 5 of 34

TIMING CHARACTERISTICS VS = 5 V, unless otherwise noted.

Table 2. Parameter Limit at TMIN to TMAX (B Version) Unit Test Conditions/Comments t1 20 ns min LE setup time t2 10 ns min DATA to CLK setup time t3 10 ns min DATA to CLK hold time t4 25 ns min CLK high duration t5 25 ns min CLK low duration t6 10 ns min CLK to LE setup time t7 20 ns min LE pulse width

Timing Diagram

CLOCK

DATA

LE

LE

DB23 (MSB) DB22 DB2 DB1(CONTROL BIT C2)

DB0 (LSB)(CONTROL BIT C1)

t1

t2 t3

t7

t6

t4 t5

0957

6-00

2

Figure 2. Timing Diagram

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ADRF6801 Data Sheet

Rev. A | Page 6 of 34

ABSOLUTE MAXIMUM RATINGS Table 3. Parameter Rating Supply Voltage, VCC1, VCC2, VCCLO,

VCCBB, and VCCRF (VS1) −0.5 V to +5.5 V

Digital I/O, CLK, DATA, and LE −0.3 V to +3.6 V RFIN 16 dBm θJA (Exposed Paddle Soldered Down) 30°C/W Maximum Junction Temperature 150°C Operating Temperature Range −40°C to +85°C Storage Temperature Range −65°C to +150°C

Stresses at or above those listed under Absolute Maximum Ratings may cause permanent damage to the product. This is a stress rating only; functional operation of the product at these or any other conditions above those indicated in the operational section of this specification is not implied. Operation beyond the maximum operating conditions for extended periods may affect product reliability.

ESD CAUTION

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Data Sheet ADRF6801

Rev. A | Page 7 of 34

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

THIRD-ORDERSDM

VCOBAND

CURRENTCAL/SET

VCO3000MHz

TO4600MHz

PHASE DETECTORAND

CHARGE PUMP

QUADRATURE÷2

SERIAL PORT

×2

ENABLEPROGRAMABLE

DIVIDER÷4

MUX

PRESCALER÷2

VCOLDO

2.5VLDO

MUX

INTEGERFRACTION

6

6

BLEED

SCALE

MODULUS

BUFFERCTRL

DIVCTRL

÷2

DIV÷1OR÷2

VCC1 1

DECL3 2

CPOUT 3

GND 4

RSET 5

REFIN 6

GND 7

MUXOUT 8

DECL2 9

VCC2 10

23 GND

24 GND

25 GNDRF

26 RFIN

27 VCCRF

28 GND

29 VCCBB

30 GND

22 VCCBB

21 GND

GN

D 1

1

DA

TA 1

2

CLK

13

GN

D 1

5

VCC

LO 1

7

GN

D 1

6

QB

BP

18

QB

BN

19

GN

D 2

0

LE

14

33 I

BB

P

34 V

CC

LO

35 G

ND

36 L

OSE

L

37 L

ON

38 L

OP

39 V

TUN

E

40 D

ECL1

32

IBB

N

31 G

ND

0881

7-00

3

Figure 3. Pin Configuration

Table 4. Pin Function Descriptions Pin No. Mnemonic Description 1 VCC1 The 5 V Power Supply Pin for VCO and PLL (VCC1). 2 DECL3 Decoupling Node for the 3.3 V LDO. Connect a 0.1 µF capacitor between this pin and ground. 3 CPOUT Charge Pump Output Pin. Connect this pin to VTUNE through the loop filter. 4, 7, 11, 15, 16, 20, 21, 23, 24, 28, 30, 31, 35

GND Connect these pins to a low impedance ground plane.

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ADRF6801 Data Sheet

Rev. A | Page 8 of 34

Pin No. Mnemonic Description 5 RSET Charge Pump Current. The nominal charge pump current can be set to 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 the following equation where the resulting value is in units of ohms.

8.374.217

×=

NOMINAL

CPSET I

IR

6 REFIN Reference Input. Nominal input level is 1 V p-p. Input range is 10 MHz to 160 MHz. 8 MUXOUT Multiplexer Output. This output can be programmed to provide the reference output signal or

the lock detect signal. The output is selected by programming the appropriate register. 9 DECL2 Decoupling Node for 2.5 V LDO. Connect a 0.1 µF capacitor between this pin and ground. 10 VCC2 The 5 V power supply pin for the 2.5 V LDO. 12 DATA Serial Data Input. The serial data is loaded MSB first with the three LSBs being the control bits. 13 CLK Serial Clock Input. This serial clock 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.

17, 34 VCCLO The 5 V Power Supply for the LO Path Blocks. 18, 19 QBBP, QBBN Demodulator Q-Channel Differential Baseband Outputs; Differential Output Impedance of 24 Ω. 22, 29 VCCBB The 5 V Power Supply for the Baseband Output Section of the Demodulator Blocks. 25 GNDRF Ground Return for RF Input Balun. 26 RFIN Single-Ended, Ground Referenced 50 Ω, RF Input. 27 VCCRF The 5 V Power Supply for the RF Input Section of the Demodulator Blocks. 32, 33 IBBN, IBBP Demodulator I-Channel Differential Baseband Outputs; Differential Output Impedance of 24 Ω. 36 LOSEL LO Select. Connect this pin to ground for the simplest operation and to completely control the LO

path and input/output direction from the register SPI programming. For additional control without register reprogramming, this input pin can determine whether the LOP and LON pins operate as inputs or outputs. LOP and LON become inputs if the LOSEL pin is set low, the LDRV bit of Register 5 is set low, and the LXL bit of Register 5 is set high. The externally applied LO drive must be at 2×LO frequency (and the LDIV bit of Register 5 (DB5) set low). LON and LOP become outputs when LOSEL is high or if the LDRV bit of Register 5 (DB3) is set high and the LXL bit of Register 5 (DB4) is set low. The output frequency is 2×LO frequency (and the LDIV bit of Register 5 (DB5) must be set high). This pin should not be left floating.

37, 38 LON, LOP Local Oscillator Input/Output. When these pins are used as output pins, a differential frequency divided version of the internal VCO is available on these pins. When the internal LO generation is disabled, an external M×LO frequency signal can be applied to these pins (where M corresponds to the LO path divider setting). (Differential Input/Output Impedance of 50 Ω)

39 VTUNE VCO Control Voltage Input. This pin is driven by the output of the loop filter. The nominal input voltage range on this pin is 1.0 V to 2.8 V.

40 DECL1 Connect a 10 µF capacitor between this pin and ground as close to the device as possible because this pin serves as the VCO supply and loop filter reference.

EP Exposed Paddle. The exposed paddle should be soldered to a low impedance ground plane.

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Data Sheet ADRF6801

Rev. A | Page 9 of 34

TYPICAL PERFORMANCE CHARACTERISTICS VS = 5 V, TA = 25°C, unless otherwise noted. LO = 750 MHz to 1150 MHz.

0

2

4

6

8

10

12

14

16

750 800 850 900 950 1000 1050 1100 1150

CO

NVE

RSI

ON

GA

IN (d

B)A

ND

INPU

T P1

dB (d

Bm

)

LO FREQUENCY (MHz)

GAIN

IP1dB

TA = +85°CTA = +25°CTA = –40°C

0957

6-00

4

Figure 4. Conversion Gain and Input P1dB vs. LO Frequency

15

17

19

21

23

25

27

29

31

33

35

750 800 850 900 950 1000 1050 1100 1150

INPU

T IP

3 (d

Bm

)

LO FREQUENCY (MHz)

TA = +85°CTA = +25°CTA = –40°C

0957

6-00

5

Figure 5. Input IP3 vs. LO Frequency

–1.0

–0.8

–0.6

–0.4

–0.2

0

0.2

0.4

0.6

0.8

1.0

750 800 850 900 950 1000 1050 1100 1150

IQ G

AIN

MIS

MAT

CH

(dB

)

LO FREQUENCY (MHz)

TA = +85°CTA = +25°CTA = –40°C

0957

6-00

6

Figure 6. IQ Gain Mismatch vs. LO Frequency

50

55

60

65

70

75

80

750 800 850 900 950 1000 1050 1100 1150

INPU

T IP

2 (d

Bm

)

LO FREQUENCY (MHz)

TA = +85°CTA = +25°CTA = –40°C

I CHANNELQ CHANNEL

0957

6-00

7

Figure 7. Input IP2 vs. LO Frequency

10

11

12

13

14

15

16

17

18

19

20

750 800 850 900 950 1000 1050 1100 1150

NO

ISE

FIG

UR

E (d

B)

LO FREQUENCY (MHz)

TA = +85°CTA = +25°CTA = –40°C

0957

6-00

8

Figure 8. Noise Figure vs. LO Frequency

–5

–4

–3

–2

–1

0

1

2

3

4

5

750 800 850 900 950 1000 1050 1100 1150

IQ Q

UA

DR

ATU

RE

PHA

SE E

RR

OR

(Deg

rees

)

LO FREQUENCY (MHz)

TA = +85°CTA = +25°CTA = –40°C

0957

6-00

9

Figure 9. IQ Quadrature Phase Error vs. LO Frequency

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ADRF6801 Data Sheet

Rev. A | Page 10 of 34

–90

–85

–80

–75

–70

–65

–60

–55

–50

750 800 850 900 950 1000 1050 1100 1150

LO-T

O-R

F FE

EDTH

RO

UG

H (d

Bm

)

LO FREQUENCY (MHz) 0957

6-01

0Figure 10. LO-to-RF Feedthrough vs. LO Frequency, LO Output Turned Off

–75

–70

–65

–60

–55

–50

–45

–40

–35

750 800 850 900 950 1000 1050 1100 1150

LO-T

O-B

B F

EED

THR

OU

GH

(dB

V rm

s)

LO FREQUENCY (MHz) 0957

6-01

1

Figure 11. LO-to-BB Feedthrough vs. LO Frequency, LO Output Turned Off

–70

–65

–60

–55

–50

–45

–40

–35

–30

750 800 850 900 950 1000 1050 1100 1150

RF-

TO-B

B F

EED

THR

OU

GH

(dB

c)

RF FREQUENCY (MHz) 0957

6-01

2

Figure 12. RF-to-BB Feedthrough vs. RF Frequency

–7

–6

–5

–4

–3

–2

–1

0

1

1 10 100

NO

RM

ALI

ZED

BA

SEB

AN

DFR

EQU

ENC

Y R

ESPO

NSE

(dB

)

BASEBAND FREQUENCY (MHz) 0957

6-01

3

Figure 13. Normalized Baseband Frequency Response vs. Baseband Frequency

0

10

20

30

40

50

60

70

80

5 10 15 20 25 30 35 40 45 50

INPU

T P1

dB (d

Bm

), IN

PUT

IP2

(dB

m),

AN

D IN

PUT

IP3

(dB

m)

BASEBAND FREQUENCY (MHz)

IP1dB

IIP3

IIP2

TA = +85°CTA = +25°CTA = –40°C

I CHANNELQ CHANNEL

0957

6-01

4

Figure 14. Input P1dB, Input IP2, and Input IP3 vs. Baseband Frequency

10

12

14

16

18

20

22

24

26

28

30

32

34

–35 –30 –25 –20 –15 –10 –5 0 5

NO

ISE

FIG

UR

E (d

B)

INPUT BLOCKER POWER (dBm) 0957

6-01

5

Figure 15. Noise Figure vs. Input Blocker Level, fLO = 900 MHz (RF Blocker 5 MHz Offset)

Page 11: 750 MHz to 1150 MHz Quadrature Demodulator with Fractional ... · 750 MHz to 1150 MHz Quadrature Demodulator with Fractional-N PLL and VCO Data Sheet ADRF6801 Rev. A Document Feedback

Data Sheet ADRF6801

Rev. A | Page 11 of 34

–40

–35

–30

–25

–20

–15

–10

–5

0

750 800 850 900 950 1000 1050 1100 1150

RF

INPU

T R

ETU

RN

LO

SS (d

B)

RF FREQUENCY (MHz) 0957

6-01

6

Figure 16. RF Input Return Loss vs. RF Frequency

–16

–14

12

–10

–8

–6

–4

–2

0

1500 1600 1700 1800 1900 2000 2100 2200 2300

LOP,

LO

N D

IFFE

REN

TIAL

OU

TPU

T R

ETU

RN

LO

SS (d

B)

LOP, LON OUTPUT FREQUENCY (MHz) 0957

6-01

7

Figure 17. LO Output Return Loss vs. LO Output Frequency, LO Output Enabled (1500 MHz to 2300 MHz), Measured through TC1-1-13 Balun

200

220

240

260

280

300

320

340

360

380

400

750 800 850 900 950 1000 1050 1100 1150

CU

RR

ENT

(mA

)

LO FREQUENCY (MHz)

TA = +85°CTA = +25°CTA = –40°C

0957

6-01

8

Figure 18. 5 V Supply Currents vs. LO Frequency, LO Output Enabled

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

–40 –15 10 35 60 85

VPTA

T VO

LTA

GE

(V)

TEMPERATURE (°C) 0957

6-01

9

Figure 19. VPTAT vs. Temperature

0.5

1.0

1.5

2.0

2.5

3.0

3.5

750 800 850 900 950 1000 1050 1100 1150

VTU

NE

VO

LTA

GE

(V)

LO FREQUENCY (MHz)

TA = +85°CTA = +25°CTA = –40°C

0957

6-02

0

Figure 20. VTUNE vs. LO Frequency

Page 12: 750 MHz to 1150 MHz Quadrature Demodulator with Fractional ... · 750 MHz to 1150 MHz Quadrature Demodulator with Fractional-N PLL and VCO Data Sheet ADRF6801 Rev. A Document Feedback

ADRF6801 Data Sheet

Rev. A | Page 12 of 34

SYNTHESIZER/PLL VS = 5 V. See the Register Structure section for recommended settings used. External loop filter bandwidths of ~130 kHz and 2.5 kHz used (see plots within this section for annotations), fREF = fPFD = 26 MHz, measured at BB output, fBB = 50 MHz, unless otherwise noted.

–160

–140

–120

–100

–80

–60

–40

1k 10k 100k 1M 10M

PHA

SE N

OIS

E (d

Bc/

Hz)

OFFSET FREQUENCY (Hz)

2.5kHz LOOP FILTERBANDWIDTH

130kHz LOOP FILTERBANDWIDTH

TA = +85°CTA = +25°CTA = –40°C

0957

6-02

1

Figure 21. Phase Noise vs. Offset Frequency, fLO = 900 MHz, Shown for Loop Filter Bandwidths of 2.5 kHz and 130 kHz

–110

–105

–100

–95

–90

–85

–80

–75

–70

750 800 850 900 950 1000 1050 1100 1150

PLL

REF

EREN

CE

SPU

RS

(dB

c)

LO FREQUENCY (MHz)

TA = +85°CTA = +25°CTA = –40°C

1 × PFD FREQUENCY3 × PFD FREQUENCY0.5 × PFD FREQUENCY

0957

6-02

2

Figure 22. PLL Reference Spurs vs. LO Frequency, Using Loop Filter Bandwidth of 130 kHz

–110

–105

–100

–95

–90

–85

–80

–75

–70

750 800 850 900 950 1000 1050 1100 1150

PLL

REF

EREN

CE

SPU

RS

(dB

c)

LO FREQUENCY (MHz)

TA = +85°CTA = +25°CTA = –40°C

2 × PFD FREQUENCY4 × PFD FREQUENCY

0957

6-02

3

Figure 23. PLL Reference Spurs vs. LO Frequency, Using Loop Filter Bandwidth of 130 kHz

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

750 800 850 900 950 1000 1050 1100 1150

INTE

GRA

TED

PH

ASE

NO

ISE

(°rm

s)

LO FREQUENCY (MHz)

TA = +85°CTA = +25°CTA = –40°C

0957

6-02

4

Figure 24. Integrated Phase Noise vs. LO Frequency (Spurs Omitted), Using Loop Filter Bandwidth of 130 kHz

–170

–150

–130

–110

–90

–70

–50

750 800 850 900 950 1000 1050 1100 1150

PHA

SE N

OIS

E (d

Bc/

Hz)

LO FREQUENCY (MHz)

1kHz OFFSET

10kHzOFFSET

5MHzOFFSET

10kHzOFFSET

1kHzOFFSET

5MHzOFFSET

130kHz LOOP FILTER BANDWIDTH2.5kHz LOOP FILTER BANDWIDTH

TA = +85°CTA = +25°CTA = –40°C

0957

6-02

5

Figure 25. Phase Noise vs. LO Frequency (1 kHz, 10 kHz, and 5 MHz Offsets), Shown for Loop Filter Bandwidths of 2.5 kHz and 130 kHz

–160

–150

–140

–130

–120

–110

–100

–90

750 800 850 900 950 1000 1050 1100 1150

PHA

SE N

OIS

E (d

Bc/

Hz)

LO FREQUENCY (MHz)

100kHz OFFSET

1MHz OFFSET100kHz OFFSET

130kHz LOOP FILTER BANDWIDTH2.5kHz LOOP FILTER BANDWIDTH

TA = +85°CTA = +25°CTA = –40°C

0957

6-02

6

1MHz OFFSET

Figure 26. Phase Noise vs. LO Frequency (100 kHz and 1 MHz Offsets), Shown for Loop Filter Bandwidths of 2.5 kHz and 130 kHz

Page 13: 750 MHz to 1150 MHz Quadrature Demodulator with Fractional ... · 750 MHz to 1150 MHz Quadrature Demodulator with Fractional-N PLL and VCO Data Sheet ADRF6801 Rev. A Document Feedback

Data Sheet ADRF6801

Rev. A | Page 13 of 34

COMPLEMENTARY CUMULATIVE DISTRIBUTION FUNCTIONS (CCDF) VS = 5 V, fLO = 900 MHz, fBB = 4.5 MHz.

0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12 14 16 18

CU

MU

LATI

VE D

ISTR

IBU

TIO

N P

ERC

ENTA

GE

(%)

GAIN (dB) AND INPUT P1dB (dBm)

GAIN

IP1dB

TA = +85°CTA = +25°CTA = –40°C

0957

6-02

7

Figure 27. Gain and Input P1dB

0

10

20

30

40

50

60

70

80

90

100

15 17 19 21 23 25 27 29 31 33 35

CU

MU

LATI

VE D

ISTR

IBU

TIO

N P

ERC

ENTA

GE

(%)

INPUT IP3 (dBm)

TA = +85°CTA = +25°CTA = –40°C

I CHANNELQ CHANNEL

0957

6-02

8

Figure 28. Input IP3

0

10

20

30

40

50

60

70

80

90

100

–0.5 –0.4 –0.3 –0.2 –0.1 0 0.1 0.2 0.3 0.4 0.5

CU

MU

LATI

VE D

ISTR

IBU

TIO

N P

ERC

ENTA

GE

(%)

IQ GAIN MISMATCH (dB)

TA = +85°CTA = +25°CTA = –40°C

0957

6-02

9

Figure 29. IQ Gain Mismatch

0

10

20

30

40

50

60

70

80

90

100

60 62 64 66 68 70 72 74 76 78 80

CU

MU

LATI

VE D

ISTR

IBU

TIO

N P

ERC

ENTA

GE

(%)

INPUT IP2 (dBm)

TA = +85°CTA = +25°CTA = –40°C

I CHANNELQ CHANNEL

0957

6-03

0

Figure 30. Input IP2

0

10

20

30

40

50

60

70

80

90

100

4 6 8 10 12 14 16 18 20 22 24

CU

MU

LATI

VE D

ISTR

IBU

TIO

N P

ERC

ENTA

GE

(%)

NOISE FIGURE (dB)

TA = +85°CTA = +25°CTA = –40°C

0957

6-13

1

Figure 31. Noise Figure

0

10

20

30

40

50

60

70

80

90

100

–5 –4 –3 –2 –1 0 1 2 3 4 5

CU

MU

LATI

VE D

ISTR

IBU

TIO

N P

ERC

ENTA

GE

(%)

IQ QUADRATURE PHASE ERROR (Degrees)

TA = +85°CTA = +25°CTA = –40°C

0957

6-13

2

Figure 32. IQ Quadrature Phase Error

Page 14: 750 MHz to 1150 MHz Quadrature Demodulator with Fractional ... · 750 MHz to 1150 MHz Quadrature Demodulator with Fractional-N PLL and VCO Data Sheet ADRF6801 Rev. A Document Feedback

ADRF6801 Data Sheet

Rev. A | Page 14 of 34

CIRCUIT DESCRIPTION The ADRF6801 integrates a high performance IQ demodulator with a state-of-the-art fractional-N PLL. The PLL also integrates a low noise VCO. The SPI port allows the user to control the fractional-N PLL functions, the demodulator LO divider functions, and optimization functions, as well as allowing for an externally applied LO.

The ADRF6801 uses a high performance mixer core that results in an exceptional input IP3 and input P1dB, with a very low output noise floor for excellent dynamic range.

LO QUADRATURE DRIVE A signal at 2× the desired mixer LO frequency is delivered to a divide-by-2 quadrature phase splitter followed by limiting amplifiers which then drive the I and Q mixers, respectively.

V-TO-I CONVERTER The RF input signal is applied to an on-chip balun which then provides both a ground referenced, 50 Ω single-ended input impedance and a differential voltage output to a V-to-I converter that converts the differential voltages to differential output currents. These currents are then applied to the emitters of the Gilbert cell mixers.

MIXERS The ADRF6801 has two double-balanced mixers: one for the in-phase channel (I channel) and one for the quadrature channel (Q channel). These mixers are based on the Gilbert cell design of four cross-connected transistors. The output currents from the two mixers are summed together in the resistive loads that then feed into the subsequent emitter follower buffers.

EMITTER FOLLOWER BUFFERS The output emitter followers drive the differential I and Q signals off chip. The output impedance is set by on-chip 12 Ω series resistors that yield a 24 Ω differential output impedance for each baseband port. The fixed output impedance forms a voltage divider with the load impedance that reduces the effective gain. For example, a 500 Ω differential load has ~0.5 dB lower effective gain than with a high (10 kΩ) differential load impedance.

The common-mode dc output levels of the emitter followers are set from VCCBB via the voltage drop across the mixer load resistors, the VBE of the output emitter follower, and the voltage drop across the 12 Ω series resistor.

BIAS CIRCUITRY There are several band gap reference circuits and three low dropout regulators (LDOs) in the ADRF6801 that generate the reference currents and voltages used by different sections. The first of the LDOs is the 2.5 V LDO, which is always active and provides the 2.5 V supply rail used by the internal digital logic blocks. The 2.5 V LDO output is connected to DECL2 (Pin 9) for the user to provide external decoupling.

The second LDO is the VCO LDO, which acts as the positive supply rail for the internal VCO. The VCO LDO output is connected to DECL2 (Pin 40) for the user to provide external decoupling. The VCO LDO can be powered down by setting Register 6, DB18 = 0, which allows the user to save power when not using the VCO.

The third LDO is the 3.3 V LDO, which acts as the 3.3 V positive supply rail for the reference input, phase frequency detector, and charge pump circuitry. The 3.3 V LDO output is connected to DECL3 (Pin 2) for the user to provide external decoupling. The 3.3 V LDO can be powered down by setting Register 6, DB19 = 0, which allows the user to save power when not using the VCO. The demodulator also has a bias circuit that supplies bias current for the mixer V-to-I stage, which then sets the bias for the mixer core. The demodulator bias cell can also be shut down by setting Register 5, DB7 = 0.

REGISTER STRUCTURE The ADRF6801 provides access to its many programmable features through a 3-wire SPI control interface that is used to program the seven internal registers. The minimum delay and hold times are shown in the timing diagram (see Figure 2). The SPI provides digital control of the internal PLL/VCO as well as several other features related to the demodulator core, on-chip referencing, and available system monitoring functions. The MUXOUT pin provides a convenient, single-pin monitor output signal that can be used to deliver a PLL lock-detect signal or an internal voltage proportional to the local junction temperature.

Note that internal calibration for the PLL must run when the ADRF6801 is initialized at a given frequency. This calibration is run automatically whenever Register 0, Register 1, or Register 2 is programmed. Because the other registers affect PLL performance, Register 0, Register 1, and Register 2 must always be programmed last. For ease of use, starting the initial programming with Register 6 and then programming the registers in descending order, ending with Register 0, is recommended. Once the PLL and other settings are programmed, the user can change the PLL frequency simply by programming Register 0, Register 1, or Register 2 as necessary.

Page 15: 750 MHz to 1150 MHz Quadrature Demodulator with Fractional ... · 750 MHz to 1150 MHz Quadrature Demodulator with Fractional-N PLL and VCO Data Sheet ADRF6801 Rev. A Document Feedback

Data Sheet ADRF6801

Rev. A | Page 15 of 34

DIVIDEMODE

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 0 0 0 DM ID6 ID5 ID4 ID3 ID2 ID1 ID0 C3(0) C2(0) C1(0)

DM

0

1

ID6 ID5 ID4 ID3 ID2 ID1 ID0

0 0 1 0 1 0 1

0 0 1 0 1 1 0

0 0 1 0 1 1 1

0 0 1 1 0 0 0

... ... ... ... ... ... ...

... ... ... ... ... ... ...

0 1 1 1 0 0 0

... ... ... ... ... ... ...

... ... ... ... ... ... ...

1 1 1 0 1 1 1

1 1 1 1 0 0 0

1 1 1 1 0 0 1

1 1 1 1 0 1 0

1 1 1 1 0 1 1

...

...

119

120 (INTEGER MODE ONLY)

DIVIDE RATIO

21 (INTEGER MODE ONLY)

22 (INTEGER MODE ONLY)

23 (INTEGER MODE ONLY)

24

...

...

56 (DEFAULT)

INTEGER

INTEGER DIVIDE RATIO CONTROL BITS

DIVIDE MODE

FRACTIONAL (DEFAULT)

121 (INTEGER MODE ONLY)

122 (INTEGER MODE ONLY)

123 (INTEGER MODE ONLY)

0957

6-03

1

Figure 33. Integer Divide Control Register (R0)

Register 0—Integer Divide Control

With R0[2:0] set to 000, the on-chip integer divide control register is programmed as shown in Figure 33. The internal VCO frequency (fVCO) equation is

fVCO = fPFD × (INT + (FRAC/MOD)) × 2 (1)

where: fVCO is the output frequency of the internal VCO. INT is the preset integer divide ratio value (21 to 123 for integer mode, 24 to 119 for fractional mode). MOD is the preset fractional modulus (1 to 2047). FRAC is the preset fractional divider ratio value (0 to MOD − 1).

The integer divide ratio sets 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.

Note that the demodulator LO frequency is given by fLO = fVCO/4.

Divide Mode

Divide mode determines whether fractional mode or integer mode is used. In integer mode, the VCO output frequency, fVCO, is calculated by

fVCO = fPFD × (INT) × 2 (2)

Page 16: 750 MHz to 1150 MHz Quadrature Demodulator with Fractional ... · 750 MHz to 1150 MHz Quadrature Demodulator with Fractional-N PLL and VCO Data Sheet ADRF6801 Rev. A Document Feedback

ADRF6801 Data Sheet

Rev. A | Page 16 of 34

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 34. The MOD value is the preset fractional modulus ranging from 1 to 2047.

MODULUS DIVIDE 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 0 0 0 0 0 0 0 0 0 1

0 0 0 0 0 0 0 0 0 1 0

... ... ... ... ... ... ... ... ... ... ...

... ... ... ... ... ... ... ... ... ... ...

1 1 0 0 0 0 0 0 0 0 0

... ... ... ... ... ... ... ... ... ... ...

... ... ... ... ... ... ... ... ... ... ...

1 1 1 1 1 1 1 1 1 1 1

MODULUS VALUE

...

...

2047

CONTROL BITS

1

1536 (DEFAULT)

2

...

...

0957

6-03

2

Figure 34. Modulus Divide Control Register (R1)

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 35. The FRAC value is the preset fractional modulus ranging from 0 to MOD − 1.

FD10 FD9 FD8 FD7 FD6 FD5 FD4 FD3 FD2 FD1 FD0

0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 1

... ... ... ... ... ... ... ... ... ... ...

... ... ... ... ... ... ... ... ... ... ...

0 1 1 0 0 0 0 0 0 0 0

... ... ... ... ... ... ... ... ... ... ...

... ... ... ... ... ... ... ... ... ... ...

FRACTIONAL VALUE MUST BE LESS THAN MODULUS

FRACTIONAL VALUE

0

1

...

...

768 (DEFAULT)

...

...

<MOD

FRACTIONAL DIVIDE 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

CONTROL BITS

0 0 0 0 0 0 0 0 0 0 FD10 FD9 FD8 FD7 FD6 FD5 FD4 FD3 FD2 FD1 FD0 C3(0) C2(1) C1(0)

0957

6-03

3

Figure 35. Fractional Divide Control Register (R2)

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 36. The dither restart value can be programmed from 0 to 217 to 1, though a value of 1 is typically recommended.

DITHERENABLE

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

0 0

0 1

1 0

1 1

DEN

0

1

DITHERMAGNITUDE DITHER RESTART VALUE CONTROL BITS

DITHER MAGNITUDE

15 (DEFAULT)

7

3

1 (RECOMMENDED)

DITHER ENABLE

DISABLE

ENABLE (DEFAULT, RECOMMENDED)

DV16 DV15 DV14 DV13 DV12 DV11 DV10 DV9 DV8 DV7 DV6 DV5 DV4 DV3 DV2 DV1 DV0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1

... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...

... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

0x00001 (DEFAULT)

...

...

0x1FFFF

DITHER RESTARTVALUE

0957

6-03

4

Figure 36. Σ-Δ Modulator Dither Control Register (R3)

Page 17: 750 MHz to 1150 MHz Quadrature Demodulator with Fractional ... · 750 MHz to 1150 MHz Quadrature Demodulator with Fractional-N PLL and VCO Data Sheet ADRF6801 Rev. A Document Feedback

Data Sheet ADRF6801

Rev. A | Page 17 of 34

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 37.

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 Bit DB18 of Register 4). When using an external resistor, the value of ICP, BASE can be varied according to

[ ] 8.37250

4.217Ω , −

×

= BASECPSET

IR

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 the DB11 and DB10 bits 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-CP transfer function and can improve fractional spurs. The magnitude of the phase offset is determined by

MULTCP

OFSPFD

I ,

,5.22[deg]ΔΦθ

=

Finally, the phase offset can be either positive or negative depending on the value of the DB17 bit 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 ADRF6801 also provides a MUXOUT pin that can be programmed to output a selection of several internal signals. The default mode provides a lock-detect output that allows users to verify when the PLL has locked to the target frequency. In addition, several other internal signals can be routed to the MUXOUT pin as described in Figure 37.

Page 18: 750 MHz to 1150 MHz Quadrature Demodulator with Fractional ... · 750 MHz to 1150 MHz Quadrature Demodulator with Fractional-N PLL and VCO Data Sheet ADRF6801 Rev. A Document Feedback

ADRF6801 Data Sheet

Rev. A | Page 18 of 34

CHARGEPUMPREF

PDFPHASEOFFSET

POLARITY

CPCNTLSRC

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

0 00 11 01 1

CPS

01

CPP1 CPP0

0 00 11 01 1

CPB4 CPB3 CPB2 CPB1 CPB0

0 0 0 0 00 0 0 0 1

0 0 1 1 0

0 1 0 1 0... ... ... ... ...1 1 1 1 1

CPBD

01

CPM

01

RS1 RS0

0 00 11 01 1

RMS2 RMS1 RMS0

0 0 00 0 10 1 00 1 11 0 01 0 11 1 01 1 1

10 × 22.5°/ICP, MULT (DEFAULT)...31 × 22.5°/ICP, MULT

PFD PHASE OFFSET MULTIPLIER

0 × 22.5°/ICP, MULT1 × 22.5°/ICP, MULT

6 × 22.5°/ICP, MULT (RECOMMENDED)

BOTH ONPUMP DOWNPUMP UPTRISTATE (DEFAULT)

OUPUT MUXSOURCE

INPUT REFPATH

SOURCE

PFD PHASE OFFSETMULTIPLIER VALUE

CHARGEPUMP

CURRENTMULTIPLIER

CHARGEPUMP

CONTROL

PFD EDGESENSITIVITY

CONTROL BITSPFD ANTI-

BACKLASHDELAY

PE0

01

REFERENCE PATH EDGESENSITIVITY

FALLING EDGE (RECOMMENDED)RISING EDGE (DEFAULT)

PAB1 PAB0

0 0

0 11 01 1

PFD ANTIBACKLASHDELAY

0ns (DEFAULT, RECOMMENDED)0.5ns0.75ns0.9ns

CHARGE PUMPCONTROL

BUFFERED VERSION OF 0.5 × REFERENCE INPUT

CHARGE PUMP CONTROL SOURCE

CONTROL BASED ON STATE OF DB7/DB8 (CP CONTROL)CONTROL FROM PFD (DEFAULT)

OUTPUT MUX SOURCE

LOCK DETECT (DEFAULT)VPTATBUFFERED VERSION OF REFERENCE INPUT

PFD PHASE OFFSET POLARITY

NEGATIVEPOSITIVE (DEFAULT, RECOMMENDED)

CHARGE PUMP CURRENTREFERENCE SOURCE

INTERNAL (DEFAULT)EXTERNAL

0.25 × REFERENCE INPUT

CHARGE PUMPCURRENT MULTIPLIER

12 (DEFAULT, RECOMMENDED)34

INPUT REFERENCEPATH SOURCE

2 × REFERENCE INPUTREFERENCE INPUT (DEFAULT)0.5 × REFERENCE INPUT

BUFFERED VERSION OF 2 × REFERENCE INPUTTRISTATEBUFFERED VERSION OF 0.25 × FREFRESERVED (DO NOT USE)

PE1

01

DIVIDER PATH EDGESENSITIVITY

FALLING EDGE (RECOMMENDED)RISING EDGE (DEFAULT)

... ... ... ... ... ...

... ... ... ... ... ...

0957

6-03

5

Figure 37. Charge Pump, PFD, and Reference Path Control Register (R4)

Page 19: 750 MHz to 1150 MHz Quadrature Demodulator with Fractional ... · 750 MHz to 1150 MHz Quadrature Demodulator with Fractional-N PLL and VCO Data Sheet ADRF6801 Rev. A Document Feedback

Data Sheet ADRF6801

Rev. A | Page 19 of 34

Register 5—LO Path and Demodulator Control Register 5 controls whether the LOIP and LOIN pins act as an input or output, whether the divider before the polyphase divider is in divide-by-1 or divide-by-2, and whether the demodulator bias circuitry is enabled as detailed in Figure 38.

DEMODBIAS

ENABLE

LOFIRST

DIVIDER

LOIN/OUTCTRL

LOOUTPUTDRIVERENABLE

DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7

DMBE

DB6 DB5 DB4 DB3 DB2 DB1 DB0

0 0 0 0 0 LDIV LXL LDRV C3(1) C2(0) C1(1)

LDRV

01

LXL

01

LDIV

01

÷ 1÷ 2 (DEFAULT, NECESSARY FOR VCO USE)

LO OUTPUT DRIVERENABLE

DRIVER OFF (DEFAULT)DRIVER ON

DMBE

01

DISABLEENABLE (DEFAULT)

DEMOD BIAS ENABLE

LO IN/OUT CONTROL

LO OUTPUT (DEFAULT)LO INPUT

DIVIDE RATIO

CONTROL BITS

0 0 0 0 00 0 00 0 0 0

0957

6-03

6

Figure 38. LO Path and Demodulator Control Register (R5)

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ADRF6801 Data Sheet

Rev. A | Page 20 of 34

Register 6—VCO Control and Enables

With R6[2:0] set to 110, the VCO control and enables register is programmed as shown in Figure 39.

VCO band selection is normally selected based on BANDCAL calibration; however, the VCO band can be selected directly using Register 6. The VCO BS SRC determines whether the BANDCAL calibration determines the optimum VCO tuning band or if the external SPI interface is used to select the VCO tuning band based on the value of the VCO band select.

The VCO amplitude can be controlled through Register 6. The VCO amplitude setting can be controlled between 0 and 31 decimal, with a default value of 24.

The internal VCO can be disabled using Register 6. The internal VCO LDO can be disabled if an external clean 3.0 V supply is available.

The internal charge pump can be disabled through Register 6. Normally, the charge pump is enabled.

CHARGEPUMP

ENABLE

3.3VLDO

ENABLE

VCOENABLE

VCOSWITCH

VCOBSCSR

VBSRC

01

VCO EN

VCO LDOENABLE VCO AMPLITUDE VCO BAND SELECT

CHARGE PUMP ENABLE

VCO BAND CAL AND SW SOURCE CONTROL

BAND CAL (DEFAULT)

VCO SW

01

VCO SWITCH CONTROL FROM SPI

REGULAR (DEFAULT)BAND CAL

SPI

VCO ENABLE

DISABLEENABLE (DEFAULT)

DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0

CONTROL BITS

DB23

CPEN L3EN VCO EN VCO SW VC5 VC4 VC3 VC2 VC1 VC0 VBSRC VBS5 VBS4 VBS3 VBS2 VBS1 VBS0 C3(1) C2(1) C1(0)LVEN

01

LVEN VCO LDO ENABLE

DISABLEENABLE (DEFAULT)

01

L3EN 3.3V LDO ENABLE

DISABLEENABLE (DEFAULT)

01

CPEN

DISABLEENABLE (DEFAULT)

01

0 0 0

VC5 VC4 VC3 VC2 VC1

0 0 0 0 0... ... ... ... ...

... ... ... ... ...

... ... ... ... ...1 1 1 1 1

...63 (RECOMMENDED)

VCO AMPLITUDE

0...

...0 0 1 0 0 8 (DEFAULT)

1 0 1 1 1

VC0

0...

...

...1

0

1 47

VBS5 VBS4 VBS3 VBS2 VBS1

0 0 0 0 0... ... ... ... ...

... ... ... ... ...

VCO BAND SELECTFROM SPI

0...

...

1 0 0 0 0 32 (DEFAULT)

1 1 1 1 1

VBS0

0...

...0

1 63

0957

6-03

7

Figure 39. VCO Control and Enables (R6)

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Data Sheet ADRF6801

Rev. A | Page 21 of 34

APPLICATIONS INFORMATION BASIC CONNECTIONS The basic circuit connections for a typical ADRF6801 application are shown in Figure 40.

SUPPLY CONNECTIONS The ADRF6801 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 ADRF6801. Specifically Pin 1, Pin 2, Pin 9, Pin 10, Pin 17, Pin 22, Pin 27, Pin 29, Pin 34, and Pin 40 should be bypassed to ground using individual bypass capacitors. Pin 40 is the decoupling pin for the on-board VCO LDO, 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, see the evaluation board schematic in Figure 42.

SYNTHESIZER CONNECTIONS The ADRF6801 includes an on-board VCO and PLL for LO synthesis. An external reference must be applied for the PLL to operate. A 1 V p-p nominal external reference must be applied to Pin 6 through an ac coupling capacitor. 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 control voltage through the external loop filter that is then applied to the VTUNE pin (Pin 39). 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).

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

IBBN

LOSE

L

IBBP

GND

V CC

LO

LON

LOP

DEC

L1

VTU

NE

GND

RFIN

GND

GND

VCCBB

GND

GND

GNDRF

VCCRF

GND

VCCBB

QB

BN

GN

D

CLK

DAT A

QB

BP

VCC

L O

LEGN

D

GN

D

GND

MUXOUT

GND

RSET

DECL3

GND

CPOUT

VCC2

REFIN

VCC1

DECL2

ADRF6801

+5V

+5V

+5V

RF INPUT

+5V

+5V

EXTERNALREFERENCE

MONITOROUTPUT

R2

OPEN

+5V

SPI CONTROL IF Q-OUTPUTBALUN IF Q-OUTPUT

IF I-OUTPUTBALUN IF I-OUTPUT

CHARGE PUMPLOOP FILTER

+5V

0957

6-04

1

Figure 40. Basic Connections

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ADRF6801 Data Sheet

Rev. A | Page 22 of 34

I/Q OUTPUT CONNECTIONS The ADRF6801 has I and Q baseband outputs. Each output stage consists of emitter follower output transistors with a low differential impedance of 24 Ω and can source up to 12 mA p-p differentially. A Mini-Circuits TCM9-1+ balun is used to trans-form a single-ended 50 Ω load impedance into a nominal 450 Ω differential impedance.

RF INPUT CONNECTIONS The ADRF6801 is to be driven single-ended and can be either dc coupled or ac coupled. There is an on-chip ground referenced balun that converts the applied single-ended signal to a differential signal that is then input to the RF V-to-I converter.

CHARGE PUMP/VTUNE CONNECTIONS The ADRF6801 uses a loop filter to create the VTUNE voltage for the internal VCO. The loop filter in its simplest form is an integrating capacitor. It converts the current mode error signal coming out of the CPOUT pin into a voltage to control the VCO via the VTUNE voltage. The stock filter on the evaluation board has a bandwidth of 130 kHz. The loop filter contains seven components, four capacitors, and three resistors. Changing the values of these components changes the bandwidth of the loop filter. Note that to obtain the approximately 2.5 kHz loop band-width, the user can change the values of the following components on the evaluation board to as follows: C14 = 0.1 µF, R10 = 68 Ω, C15 = 4.7 µF, R9 = 270 Ω, C13 = 47 nF, R60 = 0 Ω, C4 = open.

LO SELECT INTERFACE The ADRF6801 has the option of either monitoring a scaled version of the internally generated LO (LOSEL pin driven high at 3.3 V) or providing an external LO source (LOSEL pin driven low to ground, the LDRV bit in Register 5 set low, and the LXL bit in Register 5 set high). See the Pin Configuration and Function Descriptions section for full operation details.

EXTERNAL LO INTERFACE The ADRF6801 provides the option to use an external signal source for the LO into the IQ demodulating mixer core. It is important to note that the applied LO signal is divided down by either 2 or 4 depending on the LO path divider bit, LDIV, in Register 5, prior to the actual IQ demodulating mixer core. The divider is determined by the register settings in the LO path and mixer control register (see the Register 5—LO Path and Demodulator Control section). The LO input pins (Pin 37 and Pin 38) present a broadband differential 50 Ω input impedance. The LOP and LON input pins must be ac-coupled. This is achieved on the evaluation board via a Mini-Circuits TC1-1-13+ balun with a 1:1 impedance ratio. When not in use, the LOP and LON pins can be left unconnected.

SETTING THE FREQUENCY OF THE PLL The frequency of the VCO/PLL, once locked, is governed by the values programmed into the PLL registers, as follows:

fPLL = fPFD × 2 × (INT + FRAC/MOD)

where: fPLL is the frequency at the VCO when the loop is locked. fPFD is the frequency at the input of the phase frequency detector. INT is the integer divide ratio programmed into Register 0. MOD is the modulus divide ratio programmed into Register 1. FRAC is the fractional value programmed into Register 2.

The practical lower limit of the reference input frequency is determined by the combination of the desired fPLL and the maximum programmable integer divide ratio of 119 and reference input frequency multiplier of 2. For a maximum fPLL of 4600 MHz,

fREF > ~fPLL/(119 × 2 × 2), or 9.7 MHz.

A lock detect signal is available as one of the selectable outputs through the MUXOUT pin, with logic high signifying that the loop is locked.

When the internal VCO is used, the actual LO frequency is

fLO = fPLL/4

REGISTER PROGRAMMING Because Register 6 controls the powering of the VCO and charge pump, it must be programmed once before programming the PLL frequency (Register 0, Register 1, and Register 2).

The registers should be programmed starting with the highest register first and then sequentially down to Register 0 last. When Register 0, Register 1, or Register 2 is programmed, an internal VCO calibration is initiated that must execute when the other registers are set. Therefore, the order must be Register 6, Register 5, Register 4, Register 3, Register 2, Register 1, and then Register 0. Whenever Register 0, Register 1, or Register 2 is written to, it initializes the VCO calibration (even if the value in these registers does not change). After the device has been powered up and the registers configured for the desired mode of operation, only Register 0, Register 1, or Register 2 must be programmed to change the LO frequency.

If none of the register values is changing from their defaults, there is no need to program them.

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Data Sheet ADRF6801

Rev. A | Page 23 of 34

EVM MEASUREMENTS EVM is a measure used to quantify the performance of a digital radio transmitter or receiver. A signal received by a receiver has all constellation points at their ideal locations; however, various imperfections in the implementation (such as magnitude imbalance, noise floor, and phase imbalance) cause the actual constellation points to deviate from their ideal locations.

In general, a demodulator exhibits three distinct EVM limitations vs. received input signal power. As signal power increases, the distortion components increase. At large enough signal levels, where the distortion components due to the harmonic non-linearities in the device are falling in-band, EVM degrades as signal levels increase. At medium signal levels, where the demodulator behaves in a linear manner and the signal is well above any notable noise contributions, the EVM has a tendency to reach an optimal level determined dominantly by either quadrature accuracy and I/Q gain match of the demodulator or the precision of the test equipment. As signal levels decrease, such that the noise is the major contribution, the EVM performance vs. the signal level exhibits a decibel-for-decibel degradation with decreasing signal level. At lower signal levels, where noise proves to be the dominant limitation, the decibel EVM proves to be directly proportional to the SNR.

The basic test setup to test EVM for the ADRF6801 consisted of an Agilent E4438C, which was used as a signal source. The 900 MHz modulated signal was driven single ended into the RFIN SMA connector of the ADRF6801 evaluation board. The IQ baseband outputs were taken differentially into two AD8130 difference amplifiers to convert the differential signals into single-ended signals. A Hewlett Packard 89410A VSA was used to sample and calculate the EVM of the signal. The ADRF6801 IQ base-band output pins were presented with a 450 Ω differential load impedance.

The ADRF6801 shows excellent EVM performance for 16 QAM. Figure 41 shows the EVM of the ADRF6801 being better than −40 dB over a RF input range of about +35 dB for the 16 QAM modulated signal at a 10 MHz symbol rate. The pulse shaping filter’s roll-off (alpha) was set to 0.35.

–45

–40

–35

–30

–25

–20

–15

–10

–5

0

–65 –55 –45 –35 –25 –15 –5 5 15EV

M (d

B)

INPUT POWER (dBm) 0957

6-04

2

Figure 41. EVM vs. Input Power, EVM Measurements at fRF = 900 MHz;

fIF = 0 MHz (that is, Direct Down Conversion); 16 QAM; Symbol Rate = 10 MHz

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ADRF6801 Data Sheet

Rev. A | Page 24 of 34

EVALUATION BOARD LAYOUT AND THERMAL GROUNDING An evaluation board is available for testing the ADRF6801. The evaluation board schematic is shown in Figure 42. Table 5 provides

the component values and suggestions for modifying the component values for the various modes of operation.

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

IBB

N

LOSE

L

IBB

P

GN

D

VCC

LO

LON

LOP

DEC

L1

VTU

NE

GN

D

RFIN

GND

GND

VCCBB

GND

GND

GNDRF

VCCRF

GND

VCCBB

QB

BN

GN

D

CLK

DAT

A

QB

BP

VCC

LO

LEGN

D

GN

D

GN

D

MUXOUT

GND

RSET

DECL3

GND

CPOUT

VCC2

REFIN

VCC1

DECL2

ADRF6801

3P3V_SENSE

VCC4

VCO_LDO

0.1µF 100pF

CP

LO VCC_LO

0.1µF

VCC_BB

100pF

VCC_RF

1nF1nF

RFIN

100pF

VCC_BB

C1422pF C15

2.7nF

R103kΩ

R9

QOUT_SE

0.1µF100pF

VCC_LO

OUTPUT_EN

REFIN

REFOUT

2P5V0Ω

0Ω 0Ω

VCC2

NET NAME

LEGEND

TEST POINT

SMA INPUT/OUTPUT

49.9Ω1nF

R47

R48R44

R43

R42C290.1µF

P3

T1

R2

R8

C12C11

C10100pF

C90.1µF

R7

C27100pFC26

C24

R26

C25

R60Ω

C8100pF

C70.1µF

C6 C5

R37

R38

10kΩ

C136.8pF C4

22pF

VTUNE

R59OPEN

R1R12R11

C1100pF

C210µF

VCO_LDO

C31

R14

R16

R18

C16100pF

C170.1µF

C310µF

2P5V_LDO

R17VCC

C18100pF

C190.1µF

1 2 3 4 5

6 7 8 9

OPENR58

OPENR50

OPENR19

OPEN

CLK

C32

R350Ω

OPENR51

OPENC33

R30

DATA

OPENR52

OPENC34

R57

LE

R36

VTUNE

GND

GND1

GND2C21 C20

R24

C22 C23

R25

VCC_RF VCC_BB

VCC_SENSEVCC

R29 R32

C2810µF

OPEN

OPEN

OPEN

0Ω 0Ω

R21

R22

QBBP

QBBN

R23

OPEN

OPEN

IOUT_SER41

R40

R39C30

0.1µF

0.1µF

0.1µF

T2

R4

24

51

3

IBBP

IBBN

R3

OPEN

OPEN

R46OPEN

R45

R56

R55

10kΩ

10kΩ

VCCS1

13

4 5 2

OPENR49

3P3V1

VCC4

VCC_LO1

VCC

DIG_GND

P1

VCC_BB1

VCC_RF

VCC_LO

VCC

R28

R60

10kΩ

R33

0ΩLO_EXTERN

R150Ω

S2

P2

R54

T3

24

51

3

VCC_LO

R310Ω

VCC4

R130Ω0Ω

R50Ω

R20

R34

OPEN

10kΩOPEN

R530Ω

0Ω0Ω

R270Ω

0957

6-04

4

J1

LO_EXTERN

OUTPUT_EN

OSC_3P3V

VCC_SENSE

VCO_LDO

2P5V_LDO

3P3V_SENSE

VCC1

3

5

7

2

4

6

8

109

Figure 42. Evaluation Board Schematic

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Data Sheet ADRF6801

Rev. A | Page 25 of 34

The package for the ADRF6801 features an exposed paddle on the underside that should be well soldered to an exposed opening in the solder mask on the evaluation board. Figure 43 illustrates the dimensions used in the layout of the ADRF6801 footprint on the ADRF6801 evaluation board (1 mil. = 0.0254 mm).

Note 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 ADRF6801 was measured to be approximately 30°C/W in still air.

0.168

0.232

0.177

0.0350.050

0.012

0.025

0.020

0957

6-04

3

Figure 43. Evaluation Board Layout Dimensions for the ADRF6801 Package

0957

6-04

6

Figure 44. ADRF6801 Evaluation Board Top Layer

0957

6-04

7

Figure 45. ADRF6801 Evaluation Board Bottom Layer

Table 5. Evaluation Board Configuration Options Component Function Default Condition VCC, VCC2, VCC4, VCO_LDO, VCC_LO, VCC_LO1, VCC_RF, VCC_BB1, 3P3V1, 2P5V, CLK, DATA, LE, CP, DIG_GND, GND, GND1, GND2

Power supply, ground and other test points. Connect a 5 V supply to VCC.

VCC, VCC2, VCC4, VCC_LO, VCC_RF, VCC_BB1, VCC_LO1, VCO_LDO, 3P3V1, 2P5V = Components Corporation TP-104-01-02, CP, LE, CLK, DATA = Components Corporation TP-104-01-06, GND, GND1, GND2, DIG_GND = Components Corporation TP-104-01-00

R1, R6, R7, R8, R13, R15, R17, R18, R24, R25, R26, R27, R29, R31, R32, R36, R49

Power supply decoupling. Shorts or power supply decoupling resistors.

R1, R6, R7, R8 = 0 Ω (0402), R13, R15, R17 = 0 Ω (0402), R18, R24, R25, R26, R27 = 0 Ω (0402), R29, R31, R32 = 0 Ω (0402), R36 = 0 Ω (0402),

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ADRF6801 Data Sheet

Rev. A | Page 26 of 34

Component Function Default Condition C1, C2, C3, C7, C8, C9, C10, C11, C12, C16, C17, C18, C19, C20, C21, C22, C23, C24, C25, C26, C27, C28

The capacitors provide the required decoupling of the supply-related pins.

C1, C8, C10, C12 = 100 pF (0402), C16, C18, C21, C22 = 100 pF (0402), C24, C26 = 100 pF (0402), C7, C9, C11 = 0.1 µF (0402), C17, C19, C20, C23 = 0.1 µF (0402), C25, C27 = 0.1 µF (0402), C3, C2 = 10 µF (0603), C28 = 10 µF (3216)

T1, C5, C6 External LO path. The T1 transformer provides single-ended-to-differential conversion. C5 and C6 provide the necessary ac coupling.

C5, C6 = 1 nF (0603), T1 = TC1-1-13+ Mini-Circuits

R16, R14, R58, C31 REFIN input path. R14 provides a broadband 50 Ω termination followed by C31, which provides the ac coupling into REFIN. R16 provides an external connectivity to the MUXOUT feature described in Register 4. R58 provides option for connectivity to the P1-6 line of a 9-pin D-sub connector for dc measurements.

R14 = 49.9 Ω (0402), R16 = 0 Ω (0402), R58 = open (0402), C31 = 1 nF (0603)

R2, R9, R10, R11, R12, R37, R38, R59, R60, C4, C14, C15, C13

Loop filter component options. A variety of loop filter topologies is supported using component placements C4, C13, C14, C15, R9, R10, and R60. R38 and R59 provide connectivity options to numerous test points for engineering evaluation purposes. R2 provides resistor programmability of the charge pump current (see Register 4 description). R37 connects the charge pump output to the loop filter. R12 references the loop filter to the VCO_LDO. Default values on board provide a loop filter bandwidth of roughly 130 kHz using a 26 MHz PFD frequency.

R12, R37, R38 = 0 Ω (0402), R59 = open (0402), R9, R60 = 10 kΩ (0402), R10 = 3 kΩ (0402), R2, R11 = open (0402), C13 = 6.8 pF (0402), C4, C14 = 22 pF (0402), C15 = 2.7 nF (1206)

R3, R4, R5, R21, R22, R23, R39, R40, R41, R42, R43, R44, R45, R46, R47, R48, C29, C30, T2, T3, P2, P3

IF I/Q output paths. The T2 and T3 baluns provide a 9:1 impedance transformation; therefore, with a 50 Ω load on the single-ended IOUT/QOUT side, the center tap side of the balun presents a differential 450 Ω to the ADRF6806. The center taps of the baluns are ac grounded through C29 and C30. The baluns create a differential-to-single-ended conversion for ease of testing and use, but an option to have straight differential outputs is achieved via populating R3, R39, R23, and R42 with 0 Ω resistors and removing R4, R5, R21, and R22. P2 and P3 are differential measurement test points (not to be used as jumpers).

R4, R5, R21, R22, = 0 Ω (0402), R40, R43, R45, R46 = 0 Ω (0402), R47, R48 = 0 Ω (0402), R3, R23, R39, R41, R42, R44 = open (0402), C29, C30, = 0.1 µF (0402), T2, T3 = TCM9-1+ Mini-Circuits, P2, P3 = Samtec SSW-102-01-G-S

R28 RF input interface. R28 provides the single-ended RF input path to the on-chip RF input balun.

R28 = 0 Ω (0402)

R30, R35, R50, R51, R52, R57, C32, C33, C34, P1

Serial port interface. A 9-pin D-sub connector (P1) is provided for connecting to a host PC or control hardware. Optional RC filters can be installed on the CLK, DATA, and LE lines to filter the PC signals through R50 to R52 and C32 to C34. CLK, DATA, and LE signals can be observed via test points for debug purposes. R58 provides a connection to the MUXOUT for sensing lock detect through the P1 connector.

R30, R35, R57 = 0 Ω (0402), R50, R51, R52 = open (0402), C32, C33, C34 = open (0402), P1 = Tyco Electronics 5747840-3

R33, R55, R56, S1 LO select interface. The LOSEL pin, in combination with the LDRV and LXL bits in Register 5, controls whether the LOP and LON pins operate as inputs or outputs. A detailed description of how the LOSEL pin, LDRV bit, and the LXL bit work together to control the LOP and LON pins is found in Table 4 under the LOSEL pin description. Using the S1 switch, the user can pull LOSEL to a logic high (VCC/2) or a logic low (ground). Resistors R55 and R56 form a resistor divider to provide a logic high of VCC/2. LO select can also be controlled through Pin 9 of J1. The 0 Ω jumper, R33, must be installed to control LOSEL via J1.

R33 = 0 Ω (0402), R55, R56 = 10 kΩ (0402), S1 = Samtec TSW-103-08-G-S

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Data Sheet ADRF6801

Rev. A | Page 27 of 34

Component Function Default Condition J1 Engineering test points and external control. J1 is a

10-pin connector connected to various important points on the evaluation board that the user can measure or force voltages upon.

J1 = Molex Connector Corp. 10-89-7102

R19, R20, R34, R53, R54, S2 Provides ground connection for Pin 16. R20, R53 = 0 Ω (0402), R34, R54 = open (0402), R19 = open, S2 = open

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ADRF6801 Data Sheet

Rev. A | Page 28 of 34

ADRF6801 SOFTWARE The ADRF6801 evaluation board can be controlled from PCs using a USB adapter board, which is also available from Analog Devices, Inc. The USB adapter evaluation documentation and ordering information can be found on the EVAL-ADF4XXXZ-USB product page. The basic user interfaces are shown in Figure 46 and Figure 47.

The software allows the user to configure the ADRF6801 for various modes of operation. The internal synthesizer is controlled by clicking on any of the numeric values listed in RF Section.

Attempting to program Ref Input Frequency, PFD Frequency, VCO Frequency (2×LO), LO Frequency, or other values in RF Section launches the Synth Form window shown in Figure 47. Using Synth Form, the user can specify values for Local Oscillator Frequency (MHz) 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 for the new setting to take effect.

0957

6-04

8

Figure 46. Evaluation Board Software Main Window

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Data Sheet ADRF6801

Rev. A | Page 29 of 34

0957

6-04

9

Figure 47. Evaluation Board Software Synth Form Window

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ADRF6801 Data Sheet

Rev. A | Page 30 of 34

CHARACTERIZATION SETUPS Figure 48 to Figure 50 show the general characterization bench setups used extensively for the ADRF6801. The setup shown in Figure 48 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, input P1dB, output P1dB, input IP2, input IP3, IQ gain mismatch, IQ quadrature accuracy, and supply current. The evaluation board was used to perform the characterization with a Mini-Circuits TCM9-1+ balun on each of the I and Q outputs. When using the TCM9-1+ balun below 5 MHz (the specified 1 dB low frequency corner of the balun), distortion performance degrades; however, this is not the ADRF6801 degrading, merely the low frequency corner of the balun introducing distortion effects. Through this balun, the 9-to-1 impedance transformation effectively presented a 450 Ω differential load at each of the I and Q channels. The losses of the output baluns were de-embedded from all measurements.

To do phase noise and reference spur measurements, the setup shown in Figure 50 was used. Phase noise was measured at the baseband output (I or Q) at a baseband carrier frequency of 50 MHz. The baseband carrier of 50 MHz was chosen to allow phase noise measurements to be taken at frequencies of up to 20 MHz offset from the carrier. The noise figure was measured using the setup shown in Figure 49 at a baseband frequency of 10 MHz.

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Data Sheet ADRF6801

Rev. A | Page 31 of 34

R&S SMT03 SIGNAL GENERATOR

R&S SMT03 SIGNAL GENERATOR

AGILENT E3631APOWER SUPPLY

MINI-CIRCUITSZHL-42W AMPLIFIER

(SUPPLIED WITH +15V dcFOR OPERATION)

AGILENT 11636APOWER DIVIDER

(USED AS COMBINER)REF

RF2

RF1

RF SWITCH MATRIX

ADRF6801EVALUATION BOARD

RF

6dB 3dB

3dB

3dB

3dB

3dB

6dB

I CH

AGILENT 34980AMULTIFUNCTION

SWITCH(WITH 34950 AND 2×

34921 MODULES)10-PIN

CONNECTION(+5V VPOS,

DC MEASURE)

9-PIN D-SUB CONNECTION(VCO AND PLL PROGRAMMING)

RF

IEEE

IEEE

R&S SMA100SIGNAL GENERATOR

AGILENT MXASPECTRUM ANALYZER

HP 8508AVECTOR

VOLTMETER

Q CH

AGILENT DMM(FOR ISUPPLY MEAS.)

REF

IEEE

IEEE

IEEE

IEEE

IEEE

IEEE

IEEE

IEEE

IEEECH A

CH B

6dB

0957

6-05

0

IEEE

Figure 48. General Characterization Setup

Page 32: 750 MHz to 1150 MHz Quadrature Demodulator with Fractional ... · 750 MHz to 1150 MHz Quadrature Demodulator with Fractional-N PLL and VCO Data Sheet ADRF6801 Rev. A Document Feedback

ADRF6801 Data Sheet

Rev. A | Page 32 of 34

AGILENT E3631APOWER SUPPLY

REF

RF SWITCH MATRIX

ADRF6801EVALUATION BOARD

RF

6dB 3dB 6dB

I CH

10-PINCONNECTION(+5V VPOS1,

DC MEASURE)

9-PIN D-SUB CONNECTION(VCO AND PLL PROGRAMMING)

IEEE

Q CH

AGILENT DMM(FOR ISUPPLY MEAS.)

REF

E IEEE

IEEE

IEEE

IEEE

IEEE

6dB

RF1

AGILENT N8974ANOISE FIGURE ANALYZER

AGILENT 346BNOISE SOURCE

AGILENT 8665BLOW NOISE SYN

SIGNAL GENERATOR

10MHzLOW-PASS FILTER

RF

3dB

0957

6-05

1

IEEE

AGILENT 34980AMULTIFUNCTION

SWITCH(WITH 34950 AND 2×

34921 MODULES)

Figure 49. Noise Figure Characterization Setup

Page 33: 750 MHz to 1150 MHz Quadrature Demodulator with Fractional ... · 750 MHz to 1150 MHz Quadrature Demodulator with Fractional-N PLL and VCO Data Sheet ADRF6801 Rev. A Document Feedback

Data Sheet ADRF6801

Rev. A | Page 33 of 34

AGILENT E3631APOWER SUPPLY

REF

RF SWITCH MATRIX

ADRF6801EVALUATION BOARD

RF

6dB 3dB 6dB

I CH

10-PINCONNECTION(+5V VPOS1,

DC MEASURE)

9-PIN D-SUB CONNECTION(VCO AND PLL PROGRAMMING)

I E

IEEE

Q CH

AGILENT DMM(FOR ISUPPLY MEAS.)

REF

E IEEE

IEEE

IEEE

IEEE

IEEE

IEEE

IEEE

IEEE

IEEE

6dB

RF1

RF

3dB

AGILENT MXASPECTRUM ANALYZER

AGILENT E5052 SIGNAL SOURCEANALYZER

R&S SMA100SIGNAL GENERATOR

R&S SMA100SIGNAL GENERATOR

100MHzLOW-PASS FILTER

0957

6-05

2

IEEE

AGILENT 34980AMULTIFUNCTION

SWITCH(WITH 34950 AND 2×

34921 MODULES)

Figure 50. Phase Noise Characterization Setup

Page 34: 750 MHz to 1150 MHz Quadrature Demodulator with Fractional ... · 750 MHz to 1150 MHz Quadrature Demodulator with Fractional-N PLL and VCO Data Sheet ADRF6801 Rev. A Document Feedback

ADRF6801 Data Sheet

Rev. A | Page 34 of 34

OUTLINE DIMENSIONS

140

1011

3130

2120

COMPLIANT TO JEDEC STANDARDS MO-220-VJJD-2 06-0

1-20

12-D

0.50BSC

PIN 1INDICATOR

4.50 REF0.20 MIN0.50

0.400.30

TOP VIEW

12° MAX 0.80 MAX0.65 TYP

SEATINGPLANE

COPLANARITY0.08

1.000.850.80

0.300.230.18

0.05 MAX0.02 NOM

0.20 REF

4.254.10 SQ3.95

0.60 MAX

0.60 MAX

PIN 1INDICATOR

6.106.00 SQ5.90

5.855.75 SQ5.65

FOR PROPER CONNECTION OFTHE EXPOSED PAD, REFER TOTHE PIN CONFIGURATION ANDFUNCTION DESCRIPTIONSSECTION OF THIS DATA SHEET.

EXPOSEDPAD

(BOTTOM VIEW)

Figure 51. 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 Range Package Description Package Option Ordering Quantity

ADRF6801ACPZ-R7 −40°C to +85°C 40-Lead Lead Frame Chip Scale Package [LFCSP_VQ] CP-40-1 750 ADRF6801-EVALZ Evaluation Board 1 Z = RoHS Compliant Part.

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