Patent ID: 8643382

Claim:
An integrated circuit for use in a device having a capacitive transducer, the circuit having a node ( 107 ) for connection to the capacitive transducer (C MEMS ), the integrated circuit comprising; a capacitor ( 702 ; 108 ) having a first plate and a second plate, the first plate being connected to the node ( 107 ); switching means ( 704 ) coupled to the second plate of the capacitor for selectively coupling a test signal via the capacitor ( 702 ; 108 ) to the node ( 107 ) during a test mode of operation; circuitry for operating the capacitive transducer in a non-test mode of operation; and a second capacitor ( 108 ) having a first plate connected to the node ( 107 ) and a second plate connected to a reference voltage, wherein the switching means is configured to selectively connect the capacitor ( 702 ) in parallel with the second capacitor ( 108 ) during a non-test mode of operation.