A programmable-gain chopper-stabilized 2-ordder sigma-delta modulator design

To meet the requirements of high precision low frequency measurement applications, a 16-bit sigma-delta A/D converter with programmable gain was proposed. The programmable gain input allows the ADC to accept input signals directly from a strain gage or transducer removing a considerable amount of signal conditioning. The circuit could also be digitally programmed to yield four input-to-output gain values (times 1, times 2, times 32, times 128). Since the use of chopper stabilization technique in the delta-sigma converter section, low frequency error reduction was achieved. It was designed in 0.6mum CMOS process and simulation results showed all desired performances were well achieved