The circuit for controlling the oscillation frequency of an oscillation loop (66) has among others the following components--a first tunable capacitor unit (80) for providing a selectable amount of capacitance to the oscillator loop in accordance with a stored setting, and for controlling the oscillation frequency of the oscillator loop, and--a volatile storage unit (84) adaptated to store the setting of the tunable capacitor unit. The circuit further comprises a supply line (52) to the volatile storage unit and at least one other supply line (44) for the other components of said circuit. The supply line to the volatile storage unit is independent of said at least one other supply line, so that the volatile storage unit can be powered independently of other components of said circuit.