The AD623 is a low cost instrumentation amplifier from Analog Devices. It is easy to use and offers higher performance than discrete designs. It supports single/dual supply operation and has a rail-to-rail output swing. The input voltage range extends below ground by 150 mV (single supply). The device is low power, with a maximum supply current of 575 µA. Gain can be set with one external resistor, with a gain range of 1 (no resistor) to 1,000. The AD623 has high accuracy DC performance, with 0.1% gain accuracy (G = 1), 0.35% gain accuracy (G > 1), 25 ppm gain drift (G = 1), 200 µV maximum input offset voltage (AD623A), 2 µV/°C maximum input offset drift (AD623A), 100 µV maximum input offset voltage (AD623B), 1 µV/°C maximum input offset drift (AD623B) and 25 nA maximum input bias current.