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a

AD8345

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781/329-4700

www.analog.com

Fax: 781/326-8703

© Analog Devices, Inc., 2001

250 MHz–1000 MHz

Quadrature Modulator

FUNCTIONAL BLOCK DIAGRAM

16

QBBP

QBBN

15

COM3

14

COM3

13

VPS2

12

VOUT

11

COM2

10

COM3

9

1

IBBP

2

IBBN

3

COM3

4

COM1

5

LOIN

6

LOIP

7

VPS1

8

ENBL

BIAS

+

PHASE

SPLITTER

AD8345

FEATURES

250 MHz–1000 MHz Operating Frequency

+2.5 dBm P1 dB @ 800 MHz

–155 dBm/Hz Noise Floor

0.5 Degree RMS Phase Error (IS95)

0.2 dB Amplitude Balance

Single 2.7 V–5.5 V Supply

Pin-Compatible with AD8346

16-Lead Exposed Paddle TSSOP Package

APPLICATIONS

Cellular Communication Systems

W-CDMA/CDMA/GSM/PCS/ISM Transceivers

Fixed Broadband Access Systems LMDS/MMDS

Wireless LAN

Wireless Local Loop

Digital TV/CATV Modulators

Single Sideband Upconverter

PRODUCT DESCRIPTION

The AD8345 is a silicon RFIC quadrature modulator, designed

for use from 250 MHz to 1000 MHz. Its excellent phase accu-

racy and amplitude balance enable the high performance direct

modulation of an IF carrier.

The AD8345 accurately splits the external LO signal into two

quadrature components through the polyphase phase-splitter

network. The two I and Q LO components are mixed with the

baseband I and Q differential input signals. Finally, the outputs

of the two mixers are combined in the output stage to provide a

single-ended 50

Ω drive at VOUT.

APPLICATIONS

The AD8345 Modulator can be used as the IF transmit modu-

lator in digital communication systems such as GSM and PCS

transceivers. It can also directly modulate an LO signal to

produce QPSK and various QAM formats for 900 MHz com-

munication systems as well as digital TV and CATV systems.

Additionally, this quadrature modulator can be used with direct

digital synthesizers in hybrid phase-locked loops to generate

signals over a wide frequency range with millihertz resolution.

The AD8345 Modulator is supplied in a 16-lead TSSOP pack-

age with exposed paddle. Its performance is specified over a

–40

°C to +85°C temperature range. This device is fabricated on

Analog Devices’ advanced silicon bipolar process.