An Electrothermal Frequency Reference in Standard 0.7 μm CMOS

  • S. Mahdi Kashmiri
  • Kofi A. A. Makinwa
Part of the Analog Circuits and Signal Processing book series (ACSP)


This chapter describes the design and implementation of an electrothermal (thermal-diffusivity-based) frequency reference in standard 0.7 μm CMOS. The reference locks the output frequency of a variable oscillator using a frequency-locked loop to the process-insensitive phase shift of an electrothermal filter. This is in turn a function of the thermal-diffusivity of silicon, which is temperature dependent. Therefore, the loop needs to be temperature-compensated. To do this, the digital output of an on-chip band-gap temperature sensor is applied to the digitally-assisted frequency-locked loop that was described in the previous chapter. The result is a frequency reference in a 0.7 μm standard CMOS whose output frequency is stable to within ±0.1% over the military temperature range (-55°C to 125°C).


Temperature Compensation Output Frequency Bipolar Transistor Loop Filter Sampling Capacitor 
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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • S. Mahdi Kashmiri
    • 1
  • Kofi A. A. Makinwa
    • 2
  1. 1.Texas Instruments, Inc.DelftThe Netherlands
  2. 2.Delft University of TechnologyDelftThe Netherlands

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