Crystal Oscillators

  • Vincent R. von Kaenel
  • Eric A. Vittoz
  • Daniel Aebischer


A general theory for accurately analyzing the nonlinear behaviour of any crystal oscillator circuit is presented. The conditions for growing and for stable oscillation are given and the effects of nonlinearities are discussed. The special case of the three-point oscillator is analyzed in more detail. The basic conditions and trade-offs are derived analytically for the case of a lossless circuit, and current minimization by amplitude regulation is explained. As an application, a 2.1 MHz CMOS oscillator is described, which uses amplitude regulation and direct coupling of the oscillator core to the first divider to minimize power consumption. The chip, implemented in a 2 μm n-well process, includes a frequency-divider chain and the front-end for digital tuning. It operates from 1.8 to 3.5 volts with less than 500 nA. The measured frequency stability is 0.04 ppm/V and 0.1ppm/°C.


Active Device Stable Oscillation Input Capacitance Crystal Oscillator Weak Inversion 
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Copyright information

© Springer Science+Business Media Dordrecht 1996

Authors and Affiliations

  • Vincent R. von Kaenel
    • 1
  • Eric A. Vittoz
    • 1
  • Daniel Aebischer
    • 1
  1. 1.CSEMSwiss Center for Electronics and MicrotechnologyNeuchâtelSwitzerland

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