ANALOG DEVICES AD7734 Data Sheet

4-Channel, ±10 V Input Range, High Throughput, 24-Bit ∑-∆ ADC

AD7734 FEATURES FUNCTIONAL BLOCK DIAGRAM

High resolution ADC REFIN(–) REFIN(+)

24 bits no missing codes

AIN0 REFERENCE

±0.0025% nonlinearity DETECT Optimized for fast channel switching

18-bit p-p resolution (21 bits effective) at 500 Hz BUFFER

16-bit p-p resolution (19 bits effective) at 2 k Hz MUX

24-BIT

Σ−∆ ADC

14-bit p-p resolution (18 bits effective) at 15 k Hz On-chip per channel system calibration

4 single-ended analog inputs

AD7734

Input ranges +5 V, ±5 V, +10 V, ±10 V

BIASHI

Overvoltage tolerant

BIASLO

Up to ±16.5 V not affecting adjacent channel

CALIBRATION SERIAL DOUT

Up to ±50 V absolute maximum

CIRCUITRY INTERFACE DIN

3-wire serial interface

SPI™, QSPI™, MICROWIRE™, and DSP compatible Schmitt trigger on logic inputs

P0 CLOCK CONTROL RDY

I/O PORT

Single-supply operation GENERATOR LOGIC

SYNC/P1 RESET

5 V analog supply 3 V or 5 V digital supply

AVDD DGNDMCLKINMCLKOUTAGND DVDD

Package: 28-lead TSSOP

Figure 1.

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The differential reference input features “No-Reference” detect

PLCs/DCS

capability. The ADC also supports per channel system

Multiplexing applications

calibration options. The digital serial interface can be

Process control

configured for 3-wire operation and is compatible with

Industrial instrumentation

microcontrollers and digital signal processors. All interface inputs are Schmitt triggered.

GENERAL DESCRIPTION

The part is specified for operation over the extended industrial

The AD7734 is a high precision, high throughput analog front

temperature range of –40°C to +105°C.

end. True 16-bit p-p resolution is achievable with a total conversion time of 500 µs (2 k Hz channel switching), making it

Other parts in the AD7734 family are the AD7732 and

ideally suitable for high resolution multiplexing applications.

the AD7738.

The part can be configured via a simple digital interface, which

The AD7732 is similar to AD7734, but its analog front end

allows users to balance the noise performance against data

features two fully differential input channels.

throughput up to a 15.4 k Hz.

The AD7738 analog front end is configurable for four fully

The analog front end features four single-ended input channels

differential or eight single-ended input channels, features

with unipolar or true bipolar input ranges to ±10 V while

0.625 V to 2.5 V bipolar/unipolar input ranges, and accepts a

operating from a single +5 V analog supply. The part has an

common-mode input voltage from 200 m V to AVDD–300 m V.

overrange and underrange detection capability and accepts an

The AD7738 multiplexer output is pinned out externally,

analog input overvoltage to ±16.5 V without degrading the

allowing the user to implement programmable gain or signal

performance of the adjacent channels.

conditioning before being applied to the ADC.

Rev. 0 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.

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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 Tel: 781.329.4700 www.analog.com registered trademarks are the property of their respective companies. Fax: 781.326.8703 © 2003 Analog Devices, Inc. All rights reserved.