The Intersil HI7191 is a monolithic instrumentation, sigma

delta A/D converter which operates from ±5V supplies. Both

the signal and reference inputs are fully differential for

maximum flexibility and performance. An internal

Programmable Gain Instrumentation Amplifier (PGIA)

provides input gains from 1 to 128 eliminating the need for

external pre-amplifiers. The on-demand converter

auto-calibrate function is capable of removing offset and gain

errors existing in external and internal circuitry. The on-board

user programmable digital filter provides over 120dB of

60/50Hz noise rejection and allows fine tuning of resolution

and conversion speed over a wide dynamic range. The

HI7190 and HI7191 are functionally the same device, but the

HI7190 has tighter linearity specs.

The HI7191 contains a serial I/O port and is compatible with

most synchronous transfer formats including both the

Motorola 6805/11 series SPI and Intel 8051 series SSR

protocols. A sophisticated set of commands gives the user

control over calibration, PGIA gain, device selection, standby

mode, and several other features. The On-chip Calibration

Registers allow the user to read and write calibration data.

Features

? 20-Bit Resolution with No Missing Code

? 0.0015 Integral Non-Linearity (Typ)

? 20mV to ±2.5V Full Scale Input Ranges

? Internal PGIA with Gains of 1 to 128

? Serial Data I/O Interface, SPI Compatible

? Differential Analog and Reference Inputs

? Internal or System Calibration

? 120dB Rejection of 60/50Hz Line Noise

? Settling Time of 4 Conversions (Max) for a Step Input

? Pb-Free Plus Anneal Available (RoHS Compliant)

Applications

? Process Control and Measurement

? Industrial Weight Scales

? Part Counting Scales

? Laboratory Instrumentation

? Seismic Monitoring

? Magnetic Field Monitoring