Description
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 ondemand 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 HI7191 and HI7191 are functionally the same device so all discussion will refer to the HI7191 for simplicity.

FEATUREs
• 22-Bit Resolution with No Missing Code
• 0.0007% 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

APPLICATIONs
• Process Control and Measurement
• Industrial Weight Scales
• Part Counting Scales
• Laboratory Instrumentation
• Seismic Monitoring
• Magnetic Field Monitoring
• Additional Reference Literature
    - TB348 “HI7190/1 Negative Full Scale Error vs Conversion Frequency”
    - AN9504 “A Brief Intro to Sigma Delta Conversion”
    - TB329 “Intersil Sigma Delta Calibration Technique”
    - AN9505 “Using the HI7190 Evaluation Kit”
    - TB331 “Using the HI7190 Serial Interface”
    - AN9527 “Interfacing HI7190 to a Microcontroller”
    - AN9532 “Using HI7190 in a Multiplexed System”
    - AN9601 “Using HI7190 with a Single +5V Supply”