A Thermal-Diffusivity-Based Frequency Reference in Standard CMOS With an Absolute Inaccuracy of +/- 0.1% From -55 degrees C to 125 degrees C

作者：Kashmiri S Mahdi^*; Pertijs Michiel A P; Makinwa Kofi A A

来源：IEEE Journal of Solid-State Circuits, 2010, 45(12): 2510-2520.

DOI：10.1109/JSSC.2010.2076343

• Band-gap temperature sensor
• DCO
• digitally assisted
• electrothermal frequency-locked loop
• on-chip frequency reference
• standard CMOS
• thermal-diffusivity

An on-chip frequency reference exploiting the well-defined thermal-diffusivity (TD) of IC-grade silicon has been realized in a standard 0.7 mu m CMOS process. A frequency-locked loop (FLL) locks the frequency of a digitally controlled oscillator (DCO) to the process-insensitive phase shift of an electrothermal filter (ETF). The ETF's phase shift is determined by its geometry and by the thermal diffusivity of bulk silicon (D). The temperature dependence of D is compensated for with the help of die-temperature information obtained by an on-chip band-gap temperature sensor. The resulting TD frequency reference has a nominal output frequency of 1.6 MHz and dissipates 7.8 mW from a 5 V supply. Measurements on 16 devices show that it has an absolute inaccuracy of +/-0.1% (sigma = +/-0.05%) over the military temperature range (-55 degrees C to 125 degrees C), with a worst case temperature coefficient of +/-11.2 ppm/degrees C.

• 出版日期2010-12