A 4-GS/s Digitally Interpolated 8-Bit Concurrent Binary Search ADC

This letter describes a 4-GS/s four-way time-interleaved binary search analog-to-digital converter (ADC) in 65-nm CMOS. The ADC improves the conversion speed and resolution by concurrent binary searching on overlapping search space. After concurrent searching, the two successive approximation register ADC with reference offset generate 8-bit codes which are digitally interpolated to generate 9-bit code including 1-bit redundancy. Taking advantage of the higher conversion rate in the first two cycles and digital interpolation, ADC requires only six cycles to generate a 9-bit resolution at 1-GS/s rate. Consuming 28 mW, the implemented prototype achieves 39.56-dB SNDR and 48.21-dB SFDR at Nyquist frequency.