Patent ID: 7082295

Claim:
A phase locked loop comprises: difference detector operably coupled to determine a difference signal based on a reference oscillation and a feedback oscillation; programmable charge pump operably coupled to generate a charge current based on the difference signal and a scaling signal; fixed loop filter operably coupled to convert the charge current into a control voltage, the fixed loop filter including a first capacitor, a second capacitor, a third capacitor, a first resistor and a second resistor; voltage controlled oscillator operably coupled to generate an output oscillation based on the control voltage; adjustable divider module operably coupled to generate the feedback oscillation based on the output oscillation and a divider value; and scaling module operably coupled to produce the scaling signal based on the divider value; wherein the first capacitor has a capacitance based on a gain of the voltage controlled oscillator, corner frequency of the loop filter, the charge current, and the divider value; the first resistor is coupled in series with the first capacitor, in which the first resistor has a resistance based on the gain of the voltage controlled oscillator, the corner frequency of the loop filter, the charge current, a dampening factor, and the divider value; the second capacitor is coupled in parallel with the series combination of the first resistor and the first capacitor, in which the second capacitor has a capacitance based on the capacitance of the first capacitor; the second resistor is coupled to the second capacitor, in which the second resistor has a resistance based on the first resistor; and the third capacitor is coupled to the second resistor, in which the third capacitor has a capacitance based on the capacitance of the first capacitor.