Method and circuit for frequency synthesis using a low drift current controlled oscillator with wide output frequency range

摘要

A method and circuit for frequency synthesis using a low drift current controlled oscillator configured to provide a wide output frequency and high accuracy are provided. An exemplary frequency synthesis circuit is configured for programmable control of a center frequency of the current controlled oscillator to provide a wide range of output frequencies with high accuracy. In accordance with an exemplary embodiment of the present invention, an exemplary circuit comprises a phase-locked loop (PLL) circuit comprising a phase detector, a charge pump, a current controlled oscillator and a divider circuit. For programmable control of the current controlled oscillator, the PLL circuit further comprises a trim digital-to-analog converter (DAC) configured to provide a trimmed current signal for control of the current controlled oscillator. In accordance with an exemplary embodiment of the present invention, trim values for operation of the trim DAC can be suitably located within a trim register of flash memory, such as programmable flash memory within any mixed-signal device or system.