A 25 GS/s 6b TI Two-Stage Multi-Bit Search ADC With Soft-Decision Selection Algorithm in 65 nm CMOS Academic Article uri icon


  • 1966-2012 IEEE. While high-speed analog-to-digital converter (ADC) front-ends in serial link receivers enable flexible and powerful digital signal processing-based (DSP-based) equalization, the robustness and power consumption of these ADCs can limit overall receiver energy efficiency. This paper presents a 25 GS/s 6b 8-way time-interleaved multi-bit search ADC that employs a soft-decision selection algorithm to relax track-and-hold (T/H) settling requirements and improve ADC metastability tolerance. T/H bandwidth is also improved with a new shared-input double-tail three-latch structure. Fabricated in general purpose 65 nm CMOS, the ADC occupies 0.24 mm2 total area. A signal-to-noise and distortion ratio (SNDR) of 29.6 dB is achieved at Nyquist while consuming 88 mW from a 1 V supply, translating into a figure-of-merit of 143 fJ/conversion step. A measured <10 ^{-10} metastability error rate demonstrates the effectiveness of the soft-decision selection algorithm.

published proceedings


author list (cited authors)

  • Cai, S., Tabasy, E. Z., Shafik, A., Kiran, S., Hoyos, S., & Palermo, S.

citation count

  • 10

complete list of authors

  • Cai, Shengchang||Tabasy, Ehsan Zhian||Shafik, Ayman||Kiran, Shiva||Hoyos, Sebastian||Palermo, Samuel

publication date

  • August 2017