Pullable clock oscillator

A circuit for generating an output signal with a target frequency, comprising:

• a BAW (bulk acoustic wave) oscillator, including
• a BAW resonator, and
• a variable load capacitance coupled to the BAW resonator, and responsive to a capacitance control signal to provide a selectable load capacitance;
• an oscillator driver coupled to the BAW oscillator to provide an oscillation drive signal,
• the oscillator driver including:
• a differential negative gm transconductance amplifier with cross-coupled transistors, and
• a PPRF (parasitic parallel resonance frequency) filter providing band-pass filtering at a resonance frequency substantially at the target frequency, coupled to the emitters of the cross-coupled transistors;
• the BAW oscillator responsive to the oscillation drive signal to generate the output signal with a frequency based on the selectable load capacitance.