Analog Devices AD8349 a Datasheet

700 MHz to 2700 MHz

FEATURES

Output frequency range: 700 MHz to 2700 MHz Modulation bandwidth: dc to 160 MHz (large signal BW) 1 dB output compression: 5.6 dBm @ 2140 MHz Output disable function: output below –50 dBm in < 50 ns Noise floor: –156 dBm/Hz Phase quadrature error: 0.3 degrees @ 2140 MHz Amplitude balance: 0.1 dB Single supply: 4.75 V to 5.5 V Pin compatible with AD8345/AD8346s 16-lead, exposed-paddle TSSOP package

APPLICATIONS

Cellular/PCS communication systems infrastructure

WCDMA/CDMA2000/PCS/GSM/EDGE Wireless LAN/wireless local loop LMDS/broadband wireless access systems

Quadrature Modulator

AD8349

FUNCTIONAL BLOCK DIAGRAM

IBBP

IBBN

OM1

LOIN

LOIP

VPS1

ENOP

AD8349

PHASE

SPLITTER

BIAS

Figure 1.

QBBP

QBBN

COM3

VPS2

VOUT

COM3

COM2

03570-0-001

PRODUCT DESCRIPTION

The AD8349 is a silicon, monolithic, RF quadrature modulator that is designed for use from 700 MHz to 2700 MHz. Its excellent phase accuracy and amplitude balance enable high performance direct RF modulation for communication systems.

The differential LO input signal is buffered, and then split into an in-phase (I) signal and a quadrature-phase (Q) signal using a polyphase phase splitter. These two LO signals are further buffered and then mixed with the corresponding I channel and Q channel baseband signals in two Gilbert cell mixers. The mixers’ outputs are then summed together in the output amplifier. The output amplifier is designed to drive 50 Ω loads.

The RF output can be switched on and off within 50 ns by applying a control pulse to the ENOP pin.

The AD8349 can be used as a direct-to-RF modulator in digital communication systems such as GSM, CDMA, and WCDMA base stations, and QPSK or QAM broadband wireless access transmitters. Its high dynamic range and high modulation accuracy also make it a perfect IF modulator in local multipoint distribution systems (LMDS) using complex modulation formats.

The AD8349 is fabricated using Analog Devices’ advanced complementary silicon bipolar process, and is available in a 16lead, exposed-paddle TSSOP package. Its performance is specified over a –40°C to +85°C temperature range.

Rev. A

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.

www.analog.com

AD8349

TABLE OF CONTENTS

Specifications..................................................................................... 3

Absolute Maximum Ratings............................................................ 5

ESD Caution.................................................................................. 5

Pin Configuration and Functional Descriptions.......................... 6

Equivalent Circuits........................................................................... 7

Typical Performance Characteristics............................................. 8

Circuit Description......................................................................... 14

Overview...................................................................................... 14

LO Interface................................................................................. 14

V-to-I Converter......................................................................... 14

Mixers .......................................................................................... 14

D-to-S Amplifier......................................................................... 14

Bias Circuit ..................................................................................14

Output Enable............................................................................. 14

Basic Connections .......................................................................... 15

Baseband I and Q Inputs........................................................... 15

Single-Ended Baseband Drive .................................................. 15

LO Input Drive Level ................................................................. 16

Frequency Range ........................................................................ 16

LO Input Impedance Matching ................................................16

Single-Ended LO Drive.............................................................. 17

RF Output.................................................................................... 17

Output Enable............................................................................. 17

Baseband DAC Interface........................................................... 18

AD9777 Interface ....................................................................... 18

Biasing and Filtering.................................................................. 18

Reducing Undesired Sideband Leakage .................................. 19

Reduction of LO Feedthrough ................................................. 19

Sideband Suppression and LO Feedthrough vs. Temperature

....................................................................................................... 20

Applications..................................................................................... 21

3GPP WCDMA Single-Carrier Application........................... 21

WCDMA MultiCarrier Application ........................................ 21

GSM/EDGE Application........................................................... 22

Soldering Information ............................................................... 23

LO Generation Using PLLs....................................................... 23

Transm i t DAC O p tions ............................................................. 23

Evaluation Board ............................................................................ 24

Characterization Setups................................................................. 26

SSB Setup..................................................................................... 26

Outline Dimensions....................................................................... 27

Ordering Guide .......................................................................... 27

REVISION HISTORY

11/04—Data Sheet Changed from Rev. 0 to Rev. A

Changes to Figure 25 through Figure 30 ................................11

Changes to Figure 37 through Figure 39 ................................13

Change to WCDMA MultiCarrier Application section .......21

Change to Figure 60 and Figure 61 .........................................21

11/03—Revision 0: Initial Version

Rev. A | Page 2 of 28

AD8349

SPECIFICATIONS

VS = 5 V; ambient temperature (TA) = 25°C; LO = –6 dBm; I/Q inputs = 1.2 V p-p differential sine waves in quadrature on a 400 mV dc bias; baseband frequency = 1 MHz; LO source and RF output load impedances are 50 Ω, unless otherwise noted.

Table 1.

Parameter Conditions Min Typ Max Unit

Operating Frequency 700 2700 MHz LO = 900 MHz

Output Power 1.5 4 6 dBm Output P1 dB 7.6 dBm Carrier Feedthrough –45 –30 dBm Sideband Suppression –35 –31 dBc Third Harmonic Output IP3 F1BB = 3 MHz, F2BB = 4 MHz, P Quadrature Error 1.9 degree I/Q Amplitude Balance 0.1 dB Noise Floor 20 MHz offset from LO, all BB inputs 400 mV dc bias only –155 dBm/Hz

20 MHz offset from LO, BB inputs = 1.2 V p-p differential on 400 mV dc –150 dBm/Hz

GSM Sideband Noise LO = 884.8 MHz, 6 MHz offset from LO, P

LO = 1900 MHz

Output Power 0 3.8 6 dBm Output P1dB 6.8 dBm Carrier Feedthrough –38 dBm Sideband Suppression –40 –36 dBc Third Harmonic Output IP3 F1BB = 3 MHz, F2BB = 4 MHz, P Quadrature Error 0.7 degree I/Q Amplitude Balance 0.1 dB Noise Floor 20 MHz offset from LO, all BB inputs 400 mV dc bias only –156 dBm/Hz

20 MHz offset from LO, BB inputs = 1.2 V p-p differential on 400 mV dc –150 dBm/Hz

GSM Sideband Noise LO = 1960 MHz, 6 MHz offset from LO, P

LO = 2140 MHz

Output Power –2 2.4 5.1 dBm Output P1dB 5.6 dBm Carrier Feedthrough –42 –30 dBm Sideband Suppression –43 –36 dBc Third Harmonic Output IP3 F1BB = 3 MHz, F2BB = 4 MHz, P Quadrature Error 0.3 degree I/Q Amplitude Balance 0.1 dB Noise Floor 20 MHz offset from LO, all BB inputs 400 mV dc bias only –156 dBm/Hz

20 MHz offset from LO, BB inputs = 1.2 V p-p differential on 400 mV dc –151 dBm/Hz

WCDMA Noise Floor LO = 2140 MHz. 30 MHz offset from LO, P

LO INPUTS Pins LOIP and LOIN

LO Drive Level Characterization performed at typical level –10 –6 0 dBm Nominal Impedance 50 Ω Input Return Loss Drive via 1:1 balun, LO = 2140 MHz –8.6 dB

BASEBAND INPUTS Pins IBBP, IBBN, QBBP, QBBN

I and Q Input Bias Level 400 mV Input Bias Current 11 µA Input Offset Current 1.8 µA Bandwidth (0.1 dB) LO = 1500 MHz, baseband input = 600 mV p-p sine wave on 400 mV dc 10 MHz

LO = 1500 MHz, baseband input = 60 mV p-p sine wave on 400 mV dc 24 MHz

– (FLO + (3 × FBB)), P

OUT

– (FLO + (3 × FBB)), P

OUT

– (FLO + (3 × FBB)), P

OUT

= 4 dBm –39 –36 dBc

OUT

= -4.2 dBm 21 dBm

OUT

= 2 dBm –152 dBc/Hz

OUT

= 3.8 dBm –37 –36 dBc

OUT

= –4.5 dBm 22 dBm

OUT

= 2 dBm –151 dBc/Hz

OUT

= 2.4 dBm –37 –36 dBc

OUT

= –6.5 dBm 19 dBm

OUT

= –17.3 dBm –156 dBm/Hz

CHAN

Rev. A | Page 3 of 28

AD8349

Parameter Conditions Min Typ Max Unit

Bandwidth (3 dB) LO = 1500 MHz, baseband input = 600 mV p-p sine wave on 400 mV dc 160 MHz LO = 1500 MHz, baseband input = 60 mV p-p sine wave on 400 mV dc 340 MHz OUTPUT ENABLE Pin ENOP

Off Isolation ENOP Low –78 –50 dBm

Turn-On Settling Time ENOP Low to High (90% of envelope) 20 ns

Turn-Off Settling Time ENOP High to Low (10% of envelope) 50 ns

ENOP High Level (Logic 1) 2.0 V

ENOP Low Level (Logic 0) 0.8 V POWER SUPPLIES Pins VPS1 and VPS2

Voltage 4.75 5.5 V

Supply Current ENOP = High 135 150 mA ENOP = Low 130 145 mA

The amplitude of the third harmonic relative to the single sideband power decreases with decreasing baseband drive level (see Figure 19, Figure 20, and Figure 21).

Rev. A | Page 4 of 28

AD8349

ABSOLUTE MAXIMUM RATINGS

Table 2.

Parameter Rating

Supply Voltage VPOS 5.5 V IBBP, IBBN, QBBP, QBBN 0 V, 2.5 V LOIP and LOIN 10 dBm Internal Power Dissipation 800 mW θJA (Exposed Paddle Soldered Down) 30°C/W Maximum Junction Temperature 125°C Operating Temperature Range −40°C to +85°C Storage Temperature Range −65°C to +150°C

ESD CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.

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.

Rev. A | Page 5 of 28

AD8349

PIN CONFIGURATION AND FUNCTIONAL DESCRIPTIONS

Table 3. Pin Function Descriptions

Pin No. Mnemonic Description

1, 2, 15, 16

IBBP, IBBN, QBBN, QBBP

Differential In-Phase and Quadrature Baseband Inputs. These high impedance inputs must be dc-biased to approximately 400 mV dc, and must be driven from a low impedance source. Nominal characterized ac signal swing is 600 mV p-p on each pin (100 mV to 700 mV). This results in a differential drive of 1.2 V p-p with a 400 mV dc bias. These inputs are not self-biased and must be externally biased.

3, 4 COM1

Common Pin for LO Phase Splitter and LO Buffers. COM1, COM2, and COM3 should all be connected to a ground plane via a low impedance path.

5, 6 LOIN, LOIP

Differential Local Oscillator Inputs. Internally dc-biased to approximately 1.8 V when V Pins must be ac-coupled. Single-ended drive is possible with degradation in performance.

7 VPS1

Positive Supply Voltage (4.75 V to 5.5 V) for the LO Bias-Cell and Buffer. VPS1 and VPS2 should be connected to the same supply. To ensure adequate external bypassing, connect 0.1 µF and 100 pF capacitors between VPS1 and ground.

8 ENOP

Output Enable. This pin can be used to enable or disable the RF output. Connect to high logic level for normal operation. Connect to low logic level to disable output.

9 COM2

Common Pin for the Output Amplifier. COM1, COM2, and COM3 should all be connected to a ground plane via a low impedance path.

10, 13, 14

11 VOUT

COM3

Common Pin for Input V-to-I Converters and Mixer Cores. COM1, COM2, and COM3 should all be connected to a ground plane via a low impedance path.

Device Output. Single-ended, 50 Ω internally biased RF output. Pin must be ac-coupled to the load.

12 VPS2

Positive Supply Voltage (4.75 V to 5.5 V) for the Baseband Input V-to-I Converters, Mixer Core, Band Gap Reference, and Output Amplifer. VPS1 and VPS2 should be connected to the same supply. To ensure adequate external bypassing, connect 0.1 µF and 100 pF capacitors between VPS2 and ground.

IBBP

IBBN COM1 COM1

LOIN

LOIP

VPS1

ENOP

AD8349

2 3

TOP VIEW

(Not to Scale)

4 5

6 7 8

Figure 2.

QBBP

QBBN

COM3 COM3

13 12

VPS2

VOUT

COM3

COM2

03570-0-002

Equivalent Circuit

Circuit A

= 5.0 V.

Circuit B

Circuit C

Circuit D

Rev. A | Page 6 of 28

AD8349

EQUIVALENT CIRCUITS

VPS2

VPS1

LOIN

LOIP

OM1

IBBP

COM3

Figure 3. Circuit A

03570-0-003

03570-0-004

ENOP

COM3

40Ω

Figure 5. Circuit C

VPS2

VOUT

COM2

03570-0-006

04500-0-005

Figure 4. Circuit B

Figure 6. Circuit D

Rev. A | Page 7 of 28

AD8349

TYPICAL PERFORMANCE CHARACTERISTICS

8 7 6 5 4 3 2 1 0

–1

SSB OUTPUT POWER (dBm)

–2 –3 –4

700 900 1100 1300 1500 1700 1900 2100 2300 2500 2700

Figure 7. Single Sideband (SSB) Output Power (P

(I and Q Inputs Driven in Quadrature at Baseband Frequency (F

I and Q Inputs at 1.2 V p-p Differential, T

VS = 5.25V

VS = 5V

VS = 4.75V

LO FREQUENCY (MHz)

) vs. LO Frequency (FLO)

OUT

= 25°C)

) = 1 MHz,

03570-0-007

9 8 7 6 5 4 3 2 1 0

–1

1dB OUTPUT COMPRESSION (dBm)

–2 –3 –4

700 900 1100 1300 1500 1700 1900 2100 2300 2500 2700

T = +85°C

T = +25

T = –40

LO FREQUENCY (MHz)

Figure 10. SSB Output 1 dB Compression Point (OP1dB) vs. F

I and Q Inputs Driven in Quadrature , T

= 25°C)

(FBB = 1 MHz,

03570-0-010

0 –1 –2 –3 –4 –5 –6 –7 –8

OUTPUT POWER VARIATION (dB)

–9

–10

1 10 1000100

BASEBAND FREQUENCY (MHz)

600mV p-p

Figure 8. I and Q Input Bandwidth Normalized to Gain @ 1 MHz

= 1500 MHz, TA = 25°C)

4.0

3.5

3.0

2.5

2.0

1.5

1.0

SSB OUTPUT POWER (dBm)

0.5

Figure 9. SSB P

VS = 4.75V

–40–30–20–100 10203040

TEMPERATURE (°C)

vs. Temperature (FLO = 2140 MHz, FBB = 1 MHz, I and Q

OUT

VS = 5.25V

VS = 5V

Inputs Driven in Quadrature at 1.2 V p-p Differential)

60mV p-p

6050 70 80

03570-0-008

03570-0-009

–10

–15

–20

–25

–30

–35

VS = 5V

–40

–45

–50

CARRIER FEEDTHROUGH (dBm)

–55

–60

700 900 1100 1300 1500 1700 1900 2100 2300 2500 2700

Figure 11. Carrier Feedthrough vs. F

VS = 5.25V

VS = 4.75V

LO FREQUENCY (MHz)

(FBB = 1 MHz, I and Q Inputs Driven in

Quadrature at 1.2 V p-p Differential, TA = 25°C)

–20 –22 –24 –26 –28 –30 –32 –34 –36 –38 –40 –42 –44

CARRIER FEEDTHROUGH (dBm)

–46 –48

–50

–40–30–20–100 10203040

VS = 4.75V

Figure 12. Carrier Feedthrough vs. Temperature (F

VS = 5.25V

TEMPERATURE (

VS = 5V

6050 70 80

= 2140 MHz, FBB = 1 MHz,

I and Q Inputs Driven in Quadrature at 1.2 V p-p Differential, T

= 25°C)

03570-0-011

03570-0-012

Rev. A | Page 8 of 28

AD8349

–10

–15

–20

–25

–30

–35

–40

–45

–50

SIDEBAND SUPPRESSION (dBc)

–55

–60

700 900 1100 1300 1500 1700 1900 2100 2300 2500 2700

Figure 13. Sideband Suppression vs. F

VS = 5.25V

VS = 5V

LO FREQUENCY (MHz)

VS = 4.75V

(FBB = 1 MHz, I and Q Inputs

Driven in Quadrature at 1.2 V p-p Differential, T

= 25°C)

03570-0013

–10

–15

–20

–25

–30

–35

–40

–45

–50

THIRD ORDER DISTORTION (dBc)

–55

–60

700 900 1100 1300 1500 1700 1900 2100 2300 2500 2700

VS = 5V

Figure 16. Third Order Distortion vs. F

VS = 4.75V

VS = 5.25V

LO FREQUENCY (MHz)

(FBB = 1 MHz, I and Q Inputs

Driven in Quadrature at 1.2 V p-p Differential, TA = 25°C)

03570-0016

–10

–15

–20

–25

–30

–35

–40

–45

–50

SIDEBAND SUPPRESSION (dBc)

–55

–60

1 10 100

VS = 5V

BASEBAND FREQUENCY (MHz)

Figure 14. Sideband Suppression vs. F

VS = 5.25V

(FLO = 2140 MHz, I and Q Inputs

Driven in Quadrature at 1.2 V p-p Differential, T

–30

–35

–40

VS = 5V

VS = 4.75V

= 25°C)

03570-0-014

–10

–15

–20

–25

VS = 5V

–30

–35

–40

–45

–50

THIRD ORDER DISTORTION (dBc)

–55

–60

1 10 100

BASEBAND FREQUENCY (MHz)

Figure 17. Third Order Distortion vs. F

VS = 5.25V

(FLO = 2140 MHz, I and Q Inputs

VS = 4.75V

Driven in Quadrature at 1.2 V p-p Differential, T

–30

–35

–40

VS = 4.75V

VS = 5V

VS = 5.25V

= 25°C)

03570-0-017

–45

VS = 5.25V

–50

SIDEBAND SUPPRESSION (dBc)

–55

–60

–40–30–20–100 10203040

TEMPERATURE (

Figure 15. Sideband Suppression vs. Temperature (F

= 1 MHz, I and Q Inputs Driven in Quadrature at 1.2 V p-p Differential)

6050 70 80

= 2140 MHz,

03570-0-015

Rev. A | Page 9 of 28

–45

–50

THIRD ORDER DISTORTION (dBc)

–55

–60

–40–30–20–100 10203040

TEMPERATURE (

Figure 18. Third Order Distortion vs. Temperature (F

= 1 MHz, I and Q Inputs Driven in Quadrature at 1.2 V p -p Differential)

6050 70 80

= 2140 MHz,

03570-0-018

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