A differential crystal oscillator circuit is disclosed. The differential crystal oscillator circuit includes an output port. The output port includes a first terminal and a second terminal. A resonance port is included to couple a resonance element to the differential crystal oscillator circuit. The differential crystal oscillator includes a current source. A differential amplifier is included to excite the resonance element. The differential amplifier is coupled to the current source and the resonance port. The differential amplifier includes a plurality of transistors. The differential crystal oscillator circuit further includes a low pass filter that in combination with a transistor in the differential amplifier exhibits characteristics of a high pass filter. The differential amplifier is configured to use the current source as an active load.