A Low-Power Post-LPDDR4 Interface Using AC Termination at RX and an Active Inductor at TX

Jeongsik Yoo, Yeonho Lee, Yoonjae Choi, Hyunsu Park, Sanghune Park, Chulwoo Kim

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


A power reduction scheme that uses ac termination at receiver (RX) and a transmitter (TX) output driver with an active inductor part (AIP) is proposed for a point-to-point post-low-power mobile DRAM4 interface at 8 Gb/s. AC termination at the RX I/O can reduce the power consumption by preventing dc power loss. However, this causes inter symbol interference (ISI), owing to the difference in gain depending on the frequency. Thus, ac termination generates more jitter, which results in a smaller eye-opening than the conventional on-die termination. The AIP in the TX output driver reduces the low-frequency gain and the ISI caused by the ac termination. This reduces the jitter and improves the eye-opening. The proposed AIP allows changing the frequency range by adjusting the resistance (RAI ), capacitance (CAI ), and the size of the MOSFET according to the resistance (Rac ) and capacitance (Cac ) used in the ac termination at the RX. In this brief, the ac termination at the RX and the AIP in the TX were implemented in a 28-nm CMOS process and operated at 8 Gb/s with a 3-inch FR4 microstrip line including a board and a socket model. The proposed transceiver chip achieves a peak-to-peak jitterof 43.6 ps and power reduction of 31% compared with chips without ac termination and AIP.

Original languageEnglish
Pages (from-to)789-793
Number of pages5
JournalIEEE Transactions on Circuits and Systems II: Express Briefs
Issue number6
Publication statusPublished - 2018 Jun

Bibliographical note

Funding Information:
Manuscript received June 19, 2017; revised August 22, 2017; accepted August 31, 2017. Date of publication September 5, 2017; date of current version May 28, 2018. This work was supported by the National Research Foundation of Korea through the Korean Government within the Ministry of Science, ICT and Future Planning under Grant 2016R1E1A1A02922127. This brief was recommended by Associate Editor C.-T. Cheng. (Corresponding author: Chulwoo Kim.) J. Yoo is with the Department of Electrical Engineering, Korea University, Seoul 02841, South Korea, and also with the Samsung Electronics, Hwaseong 18448, South Korea.

Publisher Copyright:
© 2004-2012 IEEE.


  • AC termination
  • Active inductor
  • I/O
  • de-emphasis
  • inter symbol interference
  • near-ground signaling (NGS)
  • on-die termination
  • post-LPDDR4

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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