A 300 °C, 110-dB Sigma-Delta Modulator with Programmable Gain in Bulk CMOS

A bulk CMOS, switched-capacitor 2nd-order sigma-delta modulator with pre-amplification uses correlated double sampling, constant-gm biasing, and a modulator architecture with coefficients adjusted to improve temperature stability. The stand-alone sigma-delta modulator has a peak SNR and SNDR ges 94 dB and 87 dB, respectively, for temperature from 25 degC to 300 degC with an oversampling ratio of 256. Including the preamplifier, the modulator dynamic range is ges 110 dB at temperatures up to 300 degC