Abstract:
An integrated circuit device includes a pair of serially-connected crystal resonators arranged as a first crystal resonator, which is configured to preferentially support a fundamental resonance mode in response to an input signal, and a second crystal resonator, which is configured to preferentially support a third or higher overtone resonance mode in response to a signal generated at an output terminal of the first crystal resonator. A negative impedance converter (NIC) is also provided, which has an input terminal electrically connected to an input terminal of the first crystal resonator and an output terminal electrically connected to one of the output terminal of the first crystal resonator and the output terminal of the second crystal resonator. The NIC may be a CMOS-based NIC that is devoid of inductive reactance from a passive inductor.