Precision instrumentation amplifiers with rejustors solve high-gain apps

Instrumentation amplifiers are used in a wide variety of applications, some of which interface with sensors that produce small differential signals. In those applications, the instrumentation amplifier needs to provide high and very precise gain, while maintaining a very low offset voltage. In some conditions the differential signal coming from the sensor is in the order of very few mV, while the amplifier gain can be as high as 1,000.

Some integrated instrumentation amplifiers include gain-setting resistors and are available with a few fixed-gain options. However, when flexibility is needed and the amplified sensor signal must fit within the ADC's full-scale range, then the designer may prefer instrumentation amplifiers whose gain can be adjusted by the ratio of two external resistors. Nonetheless, one should also remember that the performance of even the best precision instrumentation amplifier can be compromised by the accuracy of the external gain-setting resistors.

This application note shows how to use a zero-drift, precision, instrumentation amplifier with a pair of rejustors and gain-setting resistors to ensure high-gain accuracy.

View the PDF document for more information.