A reference clock circuit (170), has a low-power mode, in which the frequency consumption is reduced, and including an internal counter, accumulating time spent in low-power mode. The circuit includes a crystal resonator (60), an oscillator circuit (70), and a temperature compensation circuit (80), providing a stable clock output (85). During low-power mode temperature compensation can be switched off. The circuit further provides a wakeup signal (107) after a preset time in low-power mode.