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