A high CMRR, high input impedance current-feedback instrumentation amplifier (CFIA) in 22-nm UTBB FD-SOI for signal conditioning of MEMS piezoresistive pressure sensors

A current-feedback instrumentation amplifier (CFIA) with chopper stabilization (CHS) was designed using a standard 22-nm UTBB FD-SOI process. The CFIA serves as part of the signal conditioning block for a piezoresistive pressure sensor and is composed of three subblocks, which were implemented using a fully-differential difference folded cascode, a single-ended folded cascode, and a class-AB common-drain push-pull amplifier. The IA has a 141dB open-loop gain, a 243dB CMRR, and a $29\mathrm{G} \Omega$ input impedance. It operates at 0.8 V supply voltage and consumes $15 \mu \mathrm{W}$ of power. The input-referred noise is $5 \mu \mathrm{V} /$ Hz without CHS and $1 \mu \mathrm{V} /$ Hz with CHS.