Patent ID: 7436228

Claim:
A loop circuit comprising a filter circuit comprising: first resistor circuitry that can be coupled to an output of said filter circuit through switching circuitry when a first mode of said switching circuitry is activated; second resistor circuitry coupled to said first resistor circuitry, wherein said second resistor circuitry can be coupled to said output of said filter circuit through said switching circuitry when a second mode of said switching circuitry is activated; first capacitor circuitry coupled to said first and second resistor circuitries; and second capacitor circuitry coupled to said output of said filter circuit, wherein a capacitance of said second capacitor circuitry is programmable, wherein: said first resistor circuitry comprises a first plurality of resistors; and each resistor of said first plurality of resistors can either be coupled in series with said first capacitor circuitry or bypassed; phase detector circuitry that can be coupled to said filter circuit when said first mode of said switching circuitry is activated; and phase-frequency detector circuitry that can be coupled to said filter circuit when said second mode of said switching circuitry is activated.