A 1V 350μW 92dB SNDR 24 kHz ΔΣ modulator in 0.18μm CMOS

This paper presents a high precision multi-bit audio ΔΣ modulator working under IV supply. We propose a kind of asynchronous 4-bit successive approximation quantizer without fast clock generation. Feed-forward topology with digital summing is adopted to relax the amplifier design requirement. Power efficient single stage OTA is adopted to drive the large sampling capacitor with low power consumption. Fabricated in 0.18μm standard CMOS, the modulator achieves 92dB SNDR with 24 kHz bandwidth and the power consumption is only 350μW. The active core die area is 0.64mm².