An oscillator module includes a first MOS transistor and a capacitor. The capacitor is coupled between a gate and source of the first MOS transistor. The drain of the first MOS transistor receives a first bias current and generates an oscillating output signal. A switching circuit operates in response to the oscillating output signal to selective charge and discharge the capacitor. A current sourcing circuit is configured to generate the bias current. The current sourcing circuit includes a second MOS transistor which has an identical layout to the first MOS transistor and receives a second bias current. A resistor is coupled between a gate and source of the second MOS transistor. The current sourcing circuit further includes a current mirror having an input configured to receive a reference current passing through the resistor and generate the first and second bias currents.