REV. B

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a

CMOS, ADC /4 DQPSK

Baseband Transmit Port

AD7011

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

Tel: 617/329-4700

Fax: 617/326-8703

FEATURES

Single +5 V Supply

On-Chip

/4 DQPSK Modulator

Modulator Bypass Analog Mode

Root-Raised Cosine Tx Filters,

= 0.35

Two 10-Bit D/A Converters

4th Order Reconstruction Filters

Differential Analog Outputs

On-Chip Ramp Up/Down Power Control

On-Chip Tx Offset Calibration

Dual Mode Operation, Analog and Digital

Very Low Power Dissipation, 30 mW typical

Power Down Mode < 10

A

On-Chip Voltage Reference

24-Pin SSOP

APPLICATIONS

American Digital Cellular Telephony

American Analog Cellular Telephony

GENERAL DESCRIPTION

The AD7011 is a complete low power, CMOS,

π/4 DQPSK

modulator with single +5 V power supply. The part is designed

to perform the baseband conversion of I and Q transmit wave-

forms in accordance with the American Digital Cellular Tele-

phone system (TIA IS-54).

The on-chip

π/4 Differential Quadrature Phase Shift Keying

(DQPSK) digital modulator, which includes the root raised

cosine filters, generates I and Q data in response to the transmit

data stream. The AD7011 also contains ramp control envelope

logic to shape the I and Q output waveforms when ramping up

or down at the beginning or end of a transmit burst.

Besides providing all the necessary logic to perform

π/4 DQPSK

modulation, the part also provides reconstruction filters to

smooth the DAC outputs, providing continuous time analog

outputs. The AD7011 generates differential analog outputs for

both the I and Q signals.

As it is a necessity for all digital mobile systems to use the lowest

possible power, the device has transmit and receive power-down

options. The AD7011 is housed in a space efficient 24-pin

SSOP (Shrink Small Outline Package).

FUNCTIONAL BLOCK DIAGRAM

Tx CLK (FRAME)

BOUT

QTx

V

AA

MODE1

AD7011

ITx

ITx

10-BIT

I-DAC

RECONSTRUCTION

FILTERS

2.46V

REFERENCE

POWER

QTx

CALIBRATION CIRCUITRY

MODULATOR

BYPASS

10-BIT

Q-DAC

Tx DATA (I DATA)

DGND

V

DD

MODE2

AGND

BYPASS

BIN (Q DATA)

RECONSTRUCTION

FILTERS

READY

ANALOG MODE

SERIAL

INTERFACE

π /4 DQPSK

DIGITAL

MODULATOR

MCLK

I

Q

I

Q