Compact Thermal-Diffusivity-Based Temperature Sensors in 40-nm CMOS for SoC Thermal Monitoring

Journal article (2017)

Authors

U. Sonmez Electronic Instrumentation - EEMCS
F. Sebastiano (OLD)Applied Quantum Architectures
K.A.A. Makinwa Microelectronics
Research Group
Electronic Instrumentation (EEMCS) (TU Delft)
Copyright: © 2017 U. Sonmez, F. Sebastiano, K.A.A. Makinwa
DOI
help_outline
https://doi.org/10.1109/JSSC.2016.2646798
Temperature sensors Thermal diffusivity (TD) Phase-to-digital converter Thermal monitoring Voltage-controlled oscillator (VCO)-based sigma-delta modulator
More Info
expand_more

Published Date

2017

Language

English

Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Faculty

Electrical Engineering, Mathematics and Computer Science

Department

Microelectronics

Research Group

Electronic Instrumentation

Abstract

An array of temperature sensors based on the thermal diffusivity (TD) of bulk silicon has been realized in a standard 40-nm CMOS process. In each TD sensor, a highly digital voltage-controlled oscillator-based Σ Δ ADC digitizes the temperature-dependent phase shift of an electrothermal filter (ETF). A phase calibration scheme is used to cancel the ADC's phase offset. Two types of ETF were realized, one optimized for accuracy and one optimized for resolution. Sensors based on the accuracy-optimized ETF achieved a resolution of 0.36 °C (rms) at 1 kSa/s, and inaccuracies of ±1.4 °C (3 Σ , uncalibrated) and ±0.75 °C (3 Σ, room-temperature calibrated) from -40 °C to 125 °C. Sensors based on the resolution-optimized ETFs achieved an improved resolution of 0.21 °C (rms), and inaccuracies of ±2.3 °C (3 Σ, uncalibrated) and ±1.05 °C (3 Σ, room-temperature calibrated). The sensors draw 2.8 mA from supply voltages as low as 0.9 V, and occupy only 1650 μ m2 , making them some of the smallest smart temperature sensors reported to date, and well suited for thermal monitoring applications in systems-on-chip.