A 2.1-to-2.8-GHz low-phase-noise all-digital frequency synthesizer with a time-windowed time-to-digital converter

Takashi Tokairin, Mitsuji Okada, Masaki Kitsunezuka, Tadashi Maeda, Muneo Fukaishi

Research output: Contribution to journalArticle

67 Citations (Scopus)


A 2.1-to-2.8-GHz low-power consumption all-digital phase locked loop (ADPLL) with a time-windowed time-to-digital converter (TDC) is presented. The time-windowed TDC uses a two-step structure with an inverter- and a Vernier-delay time-quantizer to improve time resolution, which results in low phase noise. Time-windowed operation is implemented in the TDC, in which a single-shot pulse-based operation is used for low power consumption. The test chip implemented in 90-nm CMOS technology exhibits in-band phase noise of -105 dBc Hz, where the loop-bandwidth is set to 500 kHz with a 40-MHz reference signal, and out-band noise of -115 dBc Hz at a 1-MHz offset frequency. The chip core occupies 0.37 mm 2 and the measured power consumption is 8.1 mA from a 1.2-V power supply.

Original languageEnglish
Article number5604672
Pages (from-to)2582-2590
Number of pages9
JournalIEEE Journal of Solid-State Circuits
Issue number12
Publication statusPublished - 2010 Dec
Externally publishedYes



  • Δσ modulator
  • all-digital phase locked loop (ADPLL)
  • digitally controlled oscillator (DCO)
  • frequency synthesizer
  • higher-order modulation
  • phase noise
  • quantization noise
  • synchronous counter
  • time-to-digital converter (TDC)

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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