REV. A

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a

AD7899

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

5 V Single Supply

14-Bit 400 kSPS ADC

FUNCTIONAL BLOCK DIAGRAM

TRACK/HOLD

AVDD

BUSY/

EOC

CLKIN

RD

CS

AD7899

+

–

14-BIT

ADC

OUTPUT

LATCH

DB0

DB13

CONVERSION

CONTROL

LOGIC

INT/EXT

CLOCK

SELECT

INT

CLOCK

SIGNAL

SCALING

2.5V

REFERENCE

6k

CONVST

OPGND

GND

STBY

FEATURES

Fast (2.2

s) 14-Bit ADC

400 kSPS Throughput Rate

0.3

s Track/Hold Acquisition Time

Single Supply Operation

Selection of Input Ranges:

10 V,

5 V and

2.5 V

0 V to 2.5 V and 0 V to 5 V

High-Speed Parallel Interface which Also Allows

Interfacing to 3 V Processors

Low Power, 80 mW Typ

Power-Saving Mode, 20

W Typ

Overvoltage Protection on Analog Inputs

Power-Down Mode via STBY Pin

GENERAL DESCRIPTION

The AD7899 is a fast, low-power, 14-bit A/D converter that

operates from a single 5 V supply. The part contains a 2.2

µs

successive-approximation ADC, a track/hold amplifier, 2.5 V

reference, on-chip clock oscillator, signal conditioning circuitry,

and a high-speed parallel interface. The part accepts analog input

ranges of

±10 V, ±5 V, ±2.5 V, 0 V to 2.5 V, and 0 V to 5 V.

Overvoltage protection on the analog input for the part allows

the input voltage to be exceeded without damaging the parts.

Speed of conversion can be controlled either by an internally

trimmed clock oscillator or by an external clock.

A conversion start signal (

CONVST) places the track/hold into

hold mode and initiates conversion. The BUSY/

EOC signal

indicates the end of the conversion.

Data is read from the part via a 14-bit parallel data bus using the

standard

CS and RD signals. Maximum throughput for the

AD7899 is 400 kSPS.

The AD7899 is available in a 28-lead SOIC and SSOP packages.

PRODUCT HIGHLIGHTS

1. The AD7899 features a fast (2.2

µs) ADC allowing through-

put rates of up to 400 kSPS.

2. The AD7899 operates from a single 5 V supply and con-

sumes only 80 mW typ making it ideal for low power and

portable applications.

3. The part offers a high-speed parallel interface. The interface

can operate in 3 V and 5 V mode allowing for easy connec-

tion to 3 V or 5 V microprocessors, microcontrollers, and

digital signal processors.

4. The part is offered in three versions with different analog

input ranges. The AD7899-1 offers the standard industrial

ranges of

±10 V and ±5 V; the AD7899-2 offers a unipolar

range of 0 V to 2.5 or 0 V to 5 V, and the AD7899-3 has an

input range of

±2.5 V.