A 0.99-pJ/b 15-Gb/s Counter-Based Adaptive Equalizer Using Single Comparator in 28-nm CMOS

Yoonjae Choi, Yeonho Lee, Hyunsu Park, Jonghyuck Choi, Jincheol Sim, Youngwook Kwon, Chulwoo Kim

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


This brief presents a low-power counter-based adaptive equalizer that does not require additional power-hungry comparators for an equalizer adaptation loop. A pulse generator in the proposed equalizer obviates the need for additional error sampling comparators. Instead, it allows the receiver to utilize an output of a data decision comparator for the equalizer adaptation by generating a pulse that indicates whether the comparator makes a firm decision for the incoming data. A single comparator is shared by the data recovery path and equalizer adaptation loop. Consequently, the proposed counter-based equalizer achieves a low power dissipation owing to the reduced number of comparators. Fabricated in a 28-nm CMOS technology, the prototype receiver occupies an active area of 0.004 mm2 and consumes only 0.99-pJ/b at 15-Gb/s.

Original languageEnglish
Pages (from-to)3189-3193
Number of pages5
JournalIEEE Transactions on Circuits and Systems II: Express Briefs
Issue number10
Publication statusPublished - 2021 Oct

Bibliographical note

Funding Information:
Manuscript received December 15, 2020; revised February 9, 2021 and March 12, 2021; accepted April 9, 2021. Date of publication April 16, 2021; date of current version September 24, 2021. This work was supported by the Institute of Information and Communications Technology Planning and Evaluation (IITP) Grant funded by the Korea Government (MSIT, Development of LPDDR5 Memory Interface for A.I Application Processor) under Grant 2019-0-01370. This brief was recommended by Associate Editor Q. Liu. (Corresponding author: Chulwoo Kim.) Yoonjae Choi, Jonghyuck Choi, Jincheol Sim, Youngwook Kwon, and Chulwoo Kim are with the Department of Electrical Engineering, Korea University, Seoul 02841, South Korea (e-mail: ckim@korea.ac.kr).

Publisher Copyright:
© 2021 IEEE.


  • Adaptive equalizer
  • continuous-time linear equalizer (CTLE)
  • counter-based adaptive equalizer
  • decision feedback equalizer (DFE)
  • receiver

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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