A 0.0088mm2 Resistor-Based Temperature Sensor Achieving 92fJ·K2 FoM in 65nm CMOS

Amr Khashaba, Junheng Zhu, Ahmed Elmallah, Mostafa Ahmed, Pavan Kumar Hanumolu

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Resistor-based temperature sensors can achieve superior performance in terms of energy efficiency and resolution compared to their BJT counterparts. Among them, Wien-(WB)[1]- and Wheatstone-Bridge (WhB)[2] -based architectures are the most popular. They employ an integrated resistor as a sensor and read out the temperature-dependent voltage/current/phase-shift using a high-resolution ΔΣ analog-to-digital converter (ADC). The high gain of the sensor combined with small quantization error of the ΔΣ ADC make these architectures the best in terms of resolution FoM (20 to 100fJ.K2)[1], [2]. However, high-resolution ΔΣ ADCs occupy large area :0.1mm2. Using a polyphase filter as a sensor, [3] proposed a frequency-locked-loop FLL-based readout scheme to solve both the area problem and the high-frequency clock requirement see Fig. 3.2.1. While it significantly reduced the area <0.01mm2, the FLL front-end circuits, specifically the zero-crossing detector (ZCD) and the charge-pump (CP), significantly limited the noise and accuracy performance, resulting in a resolution FoM of 430fJ.K2. In [4] the ZCD flicker noise and offset are cancelled using a dual-edge phase-frequency detector. However, the resulting performance is still limited by the CP noise resulting in an FoM of 260fJ.K2, which is 2.4x worse than that of the WB sensor in [1].

Original languageEnglish (US)
Title of host publication2020 IEEE International Solid-State Circuits Conference, ISSCC 2020
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages3
ISBN (Electronic)9781728132044
StatePublished - Feb 2020
Event2020 IEEE International Solid-State Circuits Conference, ISSCC 2020 - San Francisco, United States
Duration: Feb 16 2020Feb 20 2020

Publication series

NameDigest of Technical Papers - IEEE International Solid-State Circuits Conference
ISSN (Print)0193-6530


Conference2020 IEEE International Solid-State Circuits Conference, ISSCC 2020
Country/TerritoryUnited States
CitySan Francisco

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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