Instrumentation Amplifier Provides FET Input

With a low input bias current of 4 pA, the INA121 FET-input instrumentation amplifier operates from a wide ±2.25V to ±18V supply range and is well suited for amplifying the output of high-impedance sensors such as high-resistance strain-gage bridges and RTDs as well as bioelectric signals such as ECG and EEG. Specifications include low quiescent current of ±450µA, low offset voltage of ±100µV, low offset drift of 2µV/°C, low noise of 20 nV/root-Hz at 1 kHz, high CMR of 120 dB, low non-linearity error of 0.001% maximum, and input protection of ±40V. Gain can be set from 1V to 10,000V/V with a single external resistor.