CPC H03B 5/06 (2013.01) [H03B 5/36 (2013.01); H03B 5/364 (2013.01); H03L 7/099 (2013.01); H03B 2200/0012 (2013.01)] | 22 Claims |
1. A method for starting up a crystal oscillator comprising:
injecting a first clock signal into a first node of a crystal of the crystal oscillator during a startup phase of the starting up using a first tristate driver;
injecting a second clock signal into a second node of the crystal during the startup phase using a second tristate driver, the first clock signal and the second clock signal being anti-phase signals;
disabling the injecting of the first and second clock signals responsive to an end of a predetermined time period;
enabling a first amplifier circuit coupled across the first node and the second node during the startup phase and during an intermediate phase of the starting up following the startup phase; and
ending the intermediate phase responsive to an amplitude of a first node voltage on the first node exceeding a first voltage threshold.
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