A fast radix-3 SAR analog-to-digital converter

This paper presents a new radix-3 successive approximation register (SAR) analog-to-digital converter (ADC). Our proposed radix-3 SAR ADC can generate 1.6N binary bits during N comparison cycles. The radix-3 SAR ADC is 60% faster than the conventional radix-2 SAR ADC. Our prototypes are implemented with 4 and 7 ternary bits using 180nm CMOS technology. They can achieve a signal-to-quantization-noise ratio (SQNR) of 39 dB and 66 dB which are equivalent to 6.2 and 10.7 binary bits respectively.