AD7656 AD7657 AD7658 16-14-12-Bit Bipolar ADC User Manual Specifications

250 k SPS, 6-Channel, Simultaneous Sampling, Bipolar 16-/14-/12-Bit ADC

AD7656/AD7657/AD7658 FEATURES FUNCTIONAL BLOCK DIAGRAM

VDD CONVST A CONVST B CONVST C AVCC DVCC

6 independent ADCs True bipolar analog inputs

Pin-/software-selectable ranges: ±10 V, ±5 V CS

REF CLK

OSC CONTROL SER/PAR

Fast throughput rate: 250 k SPS LOGIC VDRIVE

i CMOS process technology

Low power OUTPUT

DOUT A

V1 T/H 16-/14-/12-BIT SAR DRIVERS

140 m W at 250 k SPS with 5 V supplies

Wide input bandwidth

V2 T/H 16-/14-/12-BIT SAR

86.5 d B SNR at 50 k Hz input frequency

OUTPUT

BUF DOUT B

DRIVERS

On-chip reference and reference buffers

V3 T/H 16-/14-/12-BIT SAR

Parallel, serial, and daisy-chain interface modes OUTPUT DRIVERS DOUT C

High speed serial interface

V4 T/H 16-/14-/12-BIT SAR

SPI-/QSPI™-/MICROWIRE™-/DSP-compatible DATA/

OUTPUT

CONTROL

BUF DRIVERS

LINES

Standby mode: 100 μW maximum

V5 T/H 16-/14-/12-BIT SAR

64-lead LQFP RD WR

V6 T/H 16-/14-/12-BIT SAR

APPLICATIONS

Power line monitoring systems VSS AGND DGND

Instrumentation and control systems Figure 1. Multi-axis positioning systems

GENERAL DESCRIPTION

The AD7656/AD7657/AD76581 contain six 16-/14-/12-bit, The conversion process and data acquisition are controlled fast, low power, successive approximation ADCs all in the one using CONVST signals and an internal oscillator. Three package that is designed on the i CMOS™ process (industrial CONVST pins allow independent, simultaneous sampling of CMOS). i CMOS is a process combining high voltage silicon the three ADC pairs. The AD7656/AD7657/AD7658 all have with submicron CMOS and complementary bipolar technol- a high speed parallel and serial interface, allowing the devices ogies. It enables the development of a wide range of high to interface with microprocessors or DSPs. In serial interface performance analog ICs, capable of 33 V operation in a mode, the parts have a daisy-chain feature that allows multiple footprint that no previous generation of high voltage parts ADCs to connect to a single serial interface. The AD7656/ could achieve. Unlike analog ICs using conventional CMOS AD7657/AD7658 can accommodate true bipolar input signals processes, i CMOS components can accept bipolar input signals in the ±4 × VREF range and ±2 × VREF range. The AD7656/ while providing increased performance, which dramatically AD7657/AD7658 also contain an on-chip 2.5 V reference.

reduces power consumption and package size. 0- 1AD7656/AD7657/AD7658

PRODUCT HIGHLIGHTS

The AD7656/AD7657/AD7658 feature throughput rates up

1. Six 16-/14-/12-bit, 250 k SPS ADCs on board.

to 250 k SPS. The parts contain low noise, wide bandwidth,

2. Six true bipolar, high impedance analog inputs.

track-and-hold amplifiers that can handle input frequencies

3. Parallel and high speed serial interfaces.

up to 12 MHz.

1 Protected by U.S. Patent No. 6,731,232.

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