Integrated circuit with an internal rc-oscillator and method for calibrating an rc-oscillator

Abstract

An integrated circuit () has an internal RC-oscillator () for providing an internal clock signal (CLI) having an adjustable oscillator frequency. The integrated circuit () further comprises terminals () for connecting an external LC tank () having a resonance frequency and a calibration circuit () which is configured to adjust the oscillator frequency based on the resonance frequency of the LC tank () connected during operation of the integrated circuit (). An internal auxiliary oscillator () is connected to the terminals () in a switchable fashion and is configured to generate an auxiliary clock signal (CLA) based on the resonance frequency. The calibration circuit () comprises a frequency comparator () which is configured to determine a trimming word (TRW) based on a frequency comparison of the internal clock signal (CLI) and the auxiliary clock signal (CLA). The LC tank () to be connected is an antenna for receiving a radio signal.