Circuit, system, and method for fine tuning crystal frequency accuracy

摘要

Circuits, systems, and methods for fine tuning crystal frequency accuracy are disclosed. One such circuit fine tunes crystal frequency accuracy with a tunable fractional capacitance. The circuit includes an effectively constant capacitance coupled, e.g., fixedly, with the crystal. A second capacitance is controllably coupleable with the crystal. A switching device is controllable for switchably coupling the second capacitance with the crystal. An effective capacitance value associated with the second capacitance varies according to a time associated with that switchable coupling. The crystal resonating frequency changes according to a capacitive loading thereof, which includes the first capacitance and the effective capacitance value of the second capacitance, effectively time multiplexed therewith.