Patent ID: 7339442

Claim:
An integrated circuit comprising: a tracking oscillator containing a programmable first integrated RC filter having a first pole that varies from a first designed value by a first difference and a first programmable element in the first RC filter that varies from a second designed value by a second difference; a first programmable circuit containing a second integrated RC filter having a second pole that varies from the first designed value by the first difference; a second programmable circuit containing a second programmable element that varies from the second designed value by the second difference; and an external element and switches connected between the external element and the first programmable element, the external element and the first programmable element forming a hybrid RC filter when the second programmable circuit is to be programmed, and the external element and the first programmable element disconnected from each other when the first programmable circuit is to be programmed, wherein the tracking oscillator is connectable to the first programmable circuit for providing information for programming the second RC filter using the first difference and the tracking oscillator is connectable to the second programmable circuit for providing information for programming the second programming element using the second difference.