In an integrated circuit having a number of circuit units on a single semiconductor chip, particularly in a system-on-chip integrated circuit including an integrated transceiver, interference between the circuit units is suppressed using on-chip resonant elements. Each resonant element has at least one on-chip capacitor and at least one on-chip conductive line constituting an inductance. The capacitance-inductance combinations are arranged to be resonant at one or more frequencies at which radio frequency energy is generated by the circuit units. The capacitive part of each series resonant combination is formed as a plurality of capacitor elements forming in an array to minimise self-inductance. Also disclosed is a filtering arrangement in which each circuit unit is individually supplied from the tap of a series resistive-capacitance combination to provide low-pass filtering. The resistance of such a combination may be configured as an FET to allow the circuit unit to be individually powered down to a low leakage state.