Abstract
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.
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Zaliasl, S., Salvia, J., Fiez, T., Makinwa, K., Partridge, A., Menon, V. (2016). A Micro-Power Temperature-to-Digital Converter for Use in a MEMS-Based 32 kHz Oscillator. In: Makinwa, K., Baschirotto, A., Harpe, P. (eds) Efficient Sensor Interfaces, Advanced Amplifiers and Low Power RF Systems. Springer, Cham. https://doi.org/10.1007/978-3-319-21185-5_4
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DOI: https://doi.org/10.1007/978-3-319-21185-5_4
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-21184-8
Online ISBN: 978-3-319-21185-5
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