7-bit 0.8–1.2GS/s Dynamic Architecture and Frequency Scaling subrange ADC with binary-search/flash Live Configuring Technique

Abstract

Subrange ADC with Dynamic Architecture and Frequency Scaling(DAFS) is presented, which has exponential power scaling against frequency with high-speed operation of over 1GS/s. We propose Live Configuring Technique(LCT) to adaptively configure the sub-ADC operation between binary-search and flash every clock cycle, reflecting the conversion delay. The power consumption is cut down significantly and retains high-speed operation. The prototype ADC fabricated in 65nm CMOS operates up to 1228MS/s and achieves an SNDR 36.2dB at nyquist. DAFS is active between 800-1200MS/s and when compared with the frequency power scaling with DAFS disabled, the peak power consumption cut down is 30%. Peak FoM of 85fJ/conv. was obtained at 820MS/s, which is nearly a 2x improvement compared with reported subrange ADCs.