A 15-Gb/s sub-baud-rate digital CDR

Dongwook Kim, Woo Seok Choi, Ahmed Elkholy, Jack Kenney, Pavan Kumar Hanumolu

Research output: Contribution to journalArticlepeer-review


This paper presents a sub-baud-rate clock and data recovery (CDR) circuit that can recover clock and data using only differential quarter-rate clocks. A combination of eight samplers and an integrator recover four data bits in each clock cycle. Four of the eight samplers are re-used for phase detection as well as for background calibration to improve the robustness of the CDR to process, voltage, and temperature variations. A continuous-time linear equalizer is used to compensate for inter-symbol interference up to 11 dB. The CDR prototype fabricated in a 65-nm CMOS recovers 15.2-Gb/s data using only differential 3.8-GHz clock and achieves bit error rate (BER) < 10 −12 , >10-MHz jitter tolerance (JTOL) corner, and 548 fs rms recovered clock jitter. The total power consumption is 29 mW, which translates to an energy efficiency of 1.9 pJ/bit.

Original languageEnglish (US)
Article number8599124
Pages (from-to)685-695
Number of pages11
JournalIEEE Journal of Solid-State Circuits
Issue number3
StatePublished - Mar 2019


  • Baud-rate
  • Clock and data recovery (CDR)
  • Current integrator
  • Digital CDR
  • Phase detector (PD)
  • Sub-baud-rate

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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