Title :
High-performance crystal oscillator circuits: theory and application
Author :
Vittoz, Eric A. ; Degrauwe, M.G.R. ; Bitz, Serge
Author_Institution :
Centre Suisse d´´Electron. et de Microtech., Neuchatel, Switzerland
fDate :
6/1/1988 12:00:00 AM
Abstract :
A general theory that allows the accurate linear and nonlinear analysis of any crystal oscillator circuit is presented. It is based on the high Q of the resonator and on a very few nonlimiting assumptions. The special case of the three-point oscillator, that includes Peirce and one-pin circuits, is analyzed in more detail. A clear insight into the linear behavior, including the effect of losses, is obtained by means of the circular locus of the circuit impedance. A basic condition for oscillation and simple analytic expressions are derived in the lossless case for frequency pulling, critical transconductance, and start-up time constant. The effects of nonlinearities on amplitude and on frequency stability are analyzed. As an application, a 2-MHz CMOS oscillator which uses amplitude stabilization to minimize power consumption and to eliminate the effects of nonlinearities on frequency is described. The chip, implemented in a 3- mu m p-well low-voltage process, includes a three-stage frequency divider and consumes 0.9 mu A at 1.5 V. The measured frequency stability is 0.05 p.p.m./V in the range 1.1-5 V of supply voltage. Temperature effect on the circuit itself is less than 0.1 p.p.m. from -10 to +60 degrees C.<>
Keywords :
CMOS integrated circuits; crystal resonators; frequency stability; losses; nonlinear network analysis; oscillators; radiofrequency oscillators; stability; -10 to 60 degC; 0.1 muA; 1.1 to 5 V; 2 MHz; 3 micron; CMOS oscillator; Pierce circuit; RF oscillators; amplitude stabilization; circuit impedance; circular locus; critical transconductance; crystal oscillator circuits; frequency pulling; frequency stability; linear analysis; losses; lossless case; nonlinear analysis; nonlinearities; one-pin circuits; p-well low-voltage process; resonator; start-up time constant; three-point oscillator; three-stage frequency divider; Circuit analysis; Circuit stability; Energy consumption; Frequency conversion; Frequency measurement; Impedance; Oscillators; Semiconductor device measurement; Stability analysis; Transconductance;
Journal_Title :
Solid-State Circuits, IEEE Journal of
