A 5 Gb/s energy-efficient voltage-mode transmitter using time-based de-emphasis

Saurabh Saxena, Romesh Kumar Nandwana, Pavan Kumar Hanumolu

Research output: Contribution to journalArticle

Abstract

In this paper, we present a time-based equalization scheme to implement transmit de-emphasis in voltage-mode drivers. Using two-level pulse-width modulation, this work decouples the tradeoff between impedance matching, output swing, and de-emphasis resolution in conventional voltage-mode drivers using voltage-based de-emphasis. A prototype PWM-based 5 Gb/s voltage-mode transmitter was implemented in a 90 nm CMOS process and characterized across different channels and output swings. The horizontal/vertical eye opening (BER=10 -12) at the end of 60 and 96 in stripline channels is 78 mv/0.6 UI and 8 mV/0.3 UI, respectively. Duty cycle distortion of the clock severely reduced the margins, so the overall performance can be improved by applying duty-cycle correction to clock signals. The transmitter consumes a total power 15.6 mW of which 2.5 mW is consumed in the digital PLL and 7.8 mW in the pre-/output drivers and regulators. This translates to a power efficiency of 3.1 mW/Gb/s, which compares favorably with the state of the art.

Original languageEnglish (US)
Article number6809856
Pages (from-to)1827-1836
Number of pages10
JournalIEEE Journal of Solid-State Circuits
Volume49
Issue number8
DOIs
StatePublished - Aug 2014

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Keywords

  • Digital phase-locked loop (DPLL)
  • PWM equalization,voltage-mode TX
  • wireline

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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