A 36V precision programmable gain amplifier with CMRR exceeding 120dB in all gains

A 36 V programmable gain amplifier (PGA) is presented with sub -20 muV offset and CMRR exceeding 120 dB in all gains. It is the first 36 V capable precision PGA that is implemented in a high-voltage CMOS process, allowing for several important additional functions, such as the detection of input and output fault conditions and an input switch network. This switch network in addition to acting as a 2-channel multiplexer also allows for various system-level diagnostic features. All opamps used in the PGA use chopper stabilization with a notch filter that removes chopping glitches, leading to very low offset for all gains and low 1/f noise. The input referred offset voltage is below 20 muV (G=128). The PGA is implemented in a 0.35 um CMOS process with a 36 V extension, and has a total quiescent current of 2.7 mA.