A compact instrumentation amplifier for MEMS sensor interfacing

A compact CMOS instrumentation amplifier, based on the chopper modulation approach, is proposed as a possible readout channel for integrated thermoelectric sensors. The circuit merges amplification and filtering functions. This property allows effective rejection of the modulated offset ripple. An original switching strategy involving swapping of the input and feedback port is used to improve the gain precision. The effectiveness of the technique is illustrated by means of electrical simulations performed on a prototype designed with the STMicroelectronics BCD6s process