Patent ID: 6404246
Filing Date: 2002-06-11
Classification: H03K,H03L

Abstract:
A clock synthesizer comprising:a. a reference oscillating signal having a first frequency; b. a phase detector coupled to receive the reference oscillating signal as a first input; c. a charge pump coupled to receive an up/down control from the phase detector for forming a voltage output; d. voltage controlled oscillator for producing a VCO clock signal having a second frequency in response to the voltage output; e. a precision external clock configured to generate a precision clock signal; and f. a down counter for receiving the VCO clock and forming a signal having a frequency approximately equal the first frequency and coupled as a second input to the phase detector, wherein the down counter is a programmable counter comprising a register for storing a count value, wherein the register receives a value from a calibration system, wherein the calibration system is removably coupled to receive the VCO clock signal, the calibration system being configured to compare the VCO clock signal and the precision clock signal and wherein the calibration system is configured to couple to the precision clock signal during a manufacturing process, such that the clock synthesizer is operable without the calibration system coupled thereto.