A Micro-Power Temperature-to-Digital Converter for Use in a MEMS-Based 32 kHz Oscillator

S Zaliasl, J Salvia, T Fiez, KAA Makinwa, A Partridge, V Menon

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review


This paper describes the design of a low-power energy-efficient temperature-to-digital converter (TDC) intended for the temperature compensation of a 32 kHz MEMS-based oscillator (TCXO). The compensation scheme enables a frequency stability of ±3 ppm over temperatures ranging from −40 to 85 °C. The TDC consists of an NPN-based temperature sensing element and a 15-bit second order ΔΣ modulator. A novel dynamic element matching (DEM) scheme ensures that DEM tones do not inter-modulate with the modulator’s bit-stream, thus improving the TDC’s accuracy without impacting its resolution. The TDC occupies 0.085 mm2 in a 180 nm CMOS process, draws less than 4.5 μA from a 1.5 to 3.3 V supply, and achieves a resolution of 25 mK in a conversion time of 6 ms. This corresponds to a figure of merit of 24 pJ°C2.
Original languageEnglish
Title of host publicationEfficient Sensor Interfaces, Advanced Amplifiers and Low Power RF Systems
Subtitle of host publicationAdvances in Analog Circuit Design 2015
EditorsKAA Makinwa, A Baschirotto, P Harpe
Place of PublicationCham
Number of pages15
ISBN (Electronic)978-3-319-21185-5
ISBN (Print)978-3-319-21184-8
Publication statusPublished - 2015
EventAACD 2015, Neuchatel, Switzerland - Dordrecht
Duration: 21 Apr 201523 Apr 2015


ConferenceAACD 2015, Neuchatel, Switzerland

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