论文信息 - 11.1 Dual-MEMS-resonator temperature-to-digital converter with 40 K resolution and FOM of 0.12pJK2

11.1 Dual-MEMS-resonator temperature-to-digital converter with 40 K resolution and FOM of 0.12pJK2

Precision MEMS oscillators require a temperature-to-digital converter (TDC) that adjusts the multiplication factor of a fractional-N PLL in order to compensate for the MEMS resonator's frequency variation over temperature [1]. This compensation, however, provides a path for the TDC's noise to propagate to the oscillator's output as phase noise (PN). Previous work has sought to minimize this noise, by using high-resolution TDCs, e.g., the MEMS-thermistor based TDC described in [1]. This paper presents a TDC based on dual-MEMS resonators [2-3] that has no significant impact on oscillator PN. In a 130Hz bandwidth (BW), the sensor achieves a thermal-noise-limited resolution of 40μK, leading to a resolution FOM (Energy/Conversion × Resolution2) of 0.12pJK2, 5× better than the state of the art [4].

[1] T. Kenny,et al. Stability of Silicon Microelectromechanical Systems Resonant Thermometers , 2013, IEEE Sensors Journal.

[2] Kofi A. A. Makinwa,et al. A Thermistor-Based Temperature Sensor for a Real-Time Clock With $\pm$ 2 ppm Frequency Stability , 2015, IEEE Journal of Solid-State Circuits.

[3] Fred S. Lee,et al. A Temperature-to-Digital Converter for a MEMS-Based Programmable Oscillator With $< \pm \hbox{0.5-ppm}$ Frequency Stability and $< \hbox{1-ps}$ Integrated Jitter , 2013, IEEE Journal of Solid-State Circuits.

[4] Tsung-Hsien Lin,et al. A CMOS thermistor-embedded continuous-time delta-sigma temperature sensor with a resolution of 0.01 °C , 2014, 2014 IEEE Asian Solid-State Circuits Conference (A-SSCC).

[5] J. Vig. Dual-mode oscillators for clocks and sensors , 1999, 1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027).