Fully differential CMOS programmable analogue sensor interface based on fully differential multiple differences amplifiers

A new fully differential programmable CMOS analogue interface for data acquisition in smart sensor microsystems is proposed. The architecture of this analogue front end comprises three fully differential modules where topology is based on a new fully differential multiple differences amplifier cell. This sensor interface includes a multiple input instrumentation amplifier with variable gain, a biquadratic low-pass anti-aliasing filter with tuneable cut-off frequency, and an optional fixed gain multi-input differential voltage amplifier. Each module is described, with special focus on the procedures for automatic calibration and adjustment of voltage gain and offset and cutoff frequency. Simulation results of the developed modules are presented and discussed. Finally some advantages of this structure are pointed out