Design techniques for micropower low-voltage CMOS switched-capacitor delta-sigma modulator

The design of a micropower, low-voltage switched-capacitor delta-sigma modulator that consumes only 90 μW at 1.5 V supply is described. The modulator is designed employing bootstrapped switches in order to facilitate low voltage operation. Low power dissipation is obtained through the use of biasing some transistors in weak inversion. The delta-sigma modulator achieves an 88 dB dynamic range and a peak signal to noise plus total harmonic distortion ratio of 67.1 dB with a sampling rate of 1 MHz and an oversampling ratio of 128.