A near-threshold 480 MHz 78 μw all-digital PLL with a bootstrapped DCO

Yingchieh Ho, Yu Sheng Yang, Chiachi Chang, Chau-Chin Su

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


This paper presents a near-threshold low-power all-digital PLL (ADPLL). It includes a 9-bit bootstrapped DCO (BDCO) to reduce supply voltage and power consumption, a weighted thermometer-controlled resistor network (WTRN) to achieve high linearity, and a 4-bit sigma-delta modulator to improve the resolution through dithering. The ADPLL is fabricated in a 90 nm SPRVT low-K CMOS process with a core area of 0.057 mm. The measured results demonstrate that the bootstrapped ring oscillator (BTRO) oscillates at 602 MHz under a supply of 0.5 V and consumes 49.1 μW. The ADPLL operates at 480 MHz (48 MHz) with a power consumption of 78 μW (2.4 μW) under a supply voltage of 0.5 V (0.25 V).

Original languageEnglish
Article number6606826
Pages (from-to)2805-2814
Number of pages10
JournalIEEE Journal of Solid-State Circuits
Issue number11
StatePublished - 16 Oct 2013


  • All-digital phase-locked loop (ADPLL)
  • bootstrapped circuit
  • energy-efficient design
  • low-power
  • low-voltage
  • near-threshold circuit

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