An area-efficient differential input ADC with digital common mode rejection

This paper presents a di erential input ash ADC with digital common mode rejection (DCMR) and dithered, noise shaped requantization used in a high-performance, single-poly CMOS ADC modulator IC. By avoiding the use of metal-metal capacitors, the DCMR ash ADC required 14% less area than a switched-capacitor implementation and avoided circuit implementation problems. Measurements and analysis show that the DCMR ash ADC rejects common mode noise without generating spurious tones. In the absence of common mode noise, its quantization noise power is equivalent to a conventional ash ADC.