A method for power saving in an integrated circuit device may include defining an off-switchable analog circuit island including an internal clock generating circuit, and at power-on of the integrated circuit device, supplying to clocked digital circuits of the integrated circuit device an auxiliary clock from the external controller. The auxiliary clock has a frequency determined by the external controller and being lower than the root clock signal. The method includes supplying external reset commands to the integrated circuit device until an active functioning condition of the integrated circuit device is asserted, and interrupting the supply of the auxiliary clock and enabling supply of the root clock signal to the clocked digital circuits when the active functioning condition of the integrated circuit device is asserted.