Abstract
This study proposes a novel 24-bit delta sigma analogue-to-digital
converter (ADC) for an audio system-on-chip (SOC) with a fully
differential switched-capacitor preamplifier and a capacitor-array DAC
feedback structure. This system reduces the equivalent input noise and
overcomes the nonlinearity and circuit complexity caused by the
multi-bit quantiser, This structure also improves the accuracy of the
quantiser and achieves zero static-power consumption. Combined with the
capacitor array DAC feedback structure, the entire system does not
require additional reference voltage, which reduces power consumption
and is more conducive to system integration on the chip simultaneously.
Finally, the design achieves a maximum signal-to-noise ratio (SNR) of
120 dB and a low static power consumption of 5 mW at a sampling rate of
24.576 MHz.