REV. A

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a

AD9754*

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

Tel: 781/329-4700

World Wide Web Site: http://www.analog.com

Fax: 781/326-8703

© Analog Devices, Inc., 1999

14-Bit, 125 MSPS High Performance

FUNCTIONAL BLOCK DIAGRAM

150pF

+1.20V REF

AVDD

ACOM

REFLO

ICOMP

CURRENT

SOURCE

ARRAY

+5V

SEGMENTED

SWITCHES

LSB

SWITCHES

REFIO

FS ADJ

DVDD

DCOM

CLOCK

+5V

0.1 F

CLOCK

IOUTA

IOUTB

0.1 F

LATCHES

AD9754

SLEEP

DIGITAL DATA INPUTS (DB13–DB0)

FEATURES

High Performance Member of Pin-Compatible

TxDAC Product Family

125 MSPS Update Rate

14-Bit Resolution

Excellent Spurious Free Dynamic Range Performance

SFDR to Nyquist @ 5 MHz Output: 83 dBc

Differential Current Outputs: 2 mA to 20 mA

Power Dissipation: 185 mW @ 5 V

Power-Down Mode: 20 mW @ 5 V

On-Chip 1.20 V Reference

CMOS-Compatible +2.7 V to +5.5 V Digital Interface

Package: 28-Lead SOIC, TSSOP Packages

Edge-Triggered Latches

APPLICATIONS

Wideband Communication Transmit Channel:

Direct IF

Basestations

Wireless Local Loop

Digital Radio Link

Direct Digital Synthesis (DDS)

Instrumentation

PRODUCT DESCRIPTION

The AD9754 is a 14-bit resolution, wideband, second genera-

tion member of the TxDAC series of high performance, low

power CMOS digital-to-analog-converters (DACs). The

TxDAC family, which consists of pin compatible 8-, 10-, 12-

and 14-bit DACs, is specifically optimized for the transmit

signal path of communication systems. All of the devices share

the same interface options, small outline package and pinout,

providing an upward or downward component selection path

based on performance, resolution and cost. The AD9754 offers

exceptional ac and dc performance while supporting update

rates up to 125 MSPS.

The AD9754’s flexible single-supply operating range of +4.5 V to

+5.5 V and low power dissipation are well suited for portable and

low power applications. Its power dissipation can be further reduc-

ed to a mere 65 mW with a slight degradation in performance by

lowering the full-scale current output. Also, a power-down mode

reduces the standby power dissipation to approximately 20 mW.

The AD9754 is manufactured on an advanced CMOS process.

A segmented current source architecture is combined with a

proprietary switching technique to reduce spurious components

and enhance dynamic performance. Edge-triggered input latches

and a 1.2 V temperature compensated bandgap reference have

been integrated to provide a complete monolithic DAC solution.

The digital inputs support +2.7 V and +5 V CMOS logic families.

The AD9754 is a current-output DAC with a nominal full-scale

output current of 20 mA and > 100 k

Ω output impedance.

Differential current outputs are provided to support single-

ended or differential applications. Matching between the two

current outputs ensures enhanced dynamic performance in a

differential output configuration. The current outputs may be

tied directly to an output resistor to provide two complemen-

tary, single-ended voltage outputs or fed directly into a trans-

former. The output voltage compliance range is 1.25 V.

The on-chip reference and control amplifier are configured for

maximum accuracy and flexibility. The AD9754 can be driven

by the on-chip reference or by a variety of external reference

voltages. The internal control amplifier, which provides a wide

(>10:1) adjustment span, allows the AD9754 full-scale current

to be adjusted over a 2 mA to 20 mA range while maintaining

excellent dynamic performance. Thus, the AD9754 may operate

at reduced power levels or be adjusted over a 20 dB range to

provide additional gain ranging capabilities.

The AD9754 is available in 28-lead SOIC and TSSOP packages.

It is specified for operation over the industrial temperature range.

PRODUCT HIGHLIGHTS

1. The AD9754 is a member of the wideband TxDAC high per-

formance product family that provides an upward or downward

component selection path based on resolution (8 to 14 bits),

performance and cost. The entire family of TxDACs is avail-

able in industry standard pinouts.

2. Manufactured on a CMOS process, the AD9754 uses a

proprietary switching technique that enhances dynamic per-

formance beyond that previously attainable by higher power/

cost bipolar or BiCMOS devices.

3. On-chip, edge-triggered input CMOS latches readily inter-

face to +2.7 V to +5 V CMOS logic families. The AD9754

can support update rates up to 125 MSPS.

4. A flexible single-supply operating range of +4.5 V to +5.5 V,

and a wide full-scale current adjustment span of 2 mA to

20 mA, allows the AD9754 to operate at reduced power levels.

5. The current output(s) of the AD9754 can be easily config-

ured for various single-ended or differential circuit topologies.

TxDAC is a registered trademark of Analog Devices, Inc.

*Protected by U.S. Patents Numbers 5450084, 5568145, 5689257, 5612697 and

5703519.