A 4.8-bit ENOB 5-bit 500MS/s binary-search ADC with minimized number of comparators

This paper presents a topology to improve the system linearity and reduce the complexity of high-speed binary-search ADCs. The proposed topology, when compared with previous binary-search ADC architectures, further reduces the number of comparators from 2N-1 to N for N-bit precision, the comparator structure is simplified, and it can avoid both the signal dependent offsets and the kickback noise. The proposed binary-search ADC has been implemented in 65nm CMOS process and it consumes 1.63mW at an operation frequency of 500MS/s. The measurement results demonstrate that the binary-search ADC achieves 30.7dB SNDR (4.8-bit ENOB).