A 90μW 15-bit ΔΣ ADC for digital audio

Architecture, circuit design details and measurement results for a 15 bit audio continuous-time ΔΣ modulator (CTDSM) are given. The converter, designed in a 0.18 μm CMOS technology, achieves a dynamic range of 93.5 dB in a 24 kHz bandwidth and dissipates 90 μW from a 1.8V supply. It features a third order active-RC loop filter, a very low power 4-bit flash quantizer and an efficient excess delay compensation scheme to reduce power dissipation.