GENERAL DESCRIPTION

The AD7870/AD7875/AD7876 is a fast, complete, 12-bit A/D converter. It consists of a track/hold amplifier, 8 µs successive approximation ADC, 3 V buried Zener reference and versatile interface logic. The ADC features a self-contained internal clock which is laser trimmed to guarantee accurate control of conversion time. No external clock timing components are required; the on-chip clock may he overridden by an external clock if required.

The parts offer a choice of three data output formats: a single, parallel, 12-bit word; two 8-bit bytes or serial data. Fast bus access times and standard control inputs ensure easy interfacing to modern microprocessors and digital signal processors.

FEATURES

  Complete Monolithic 12-Bit ADC with:

     2 ms Track/Hold Amplifier

     8 ms A/D Converter

     On-Chip Reference

     Laser-Trimmed Clock

     Parallel, Byte and Serial Digital Interface

  72 dB SNR at 10 kHz Input Frequency (AD7870, AD7875)

  57 ns Data Access Time

  Low Power: –60 mW typ

  Variety of Input Ranges:

     ±63 V for AD7870

     0 V to ±5 V for AD7875

     ±610 V for AD7876