A low-pass filter comprising: a filter input terminal; a filter output terminal; a filter FET configured to provide a resistance between the filter input terminal and the filter output terminal; a filter capacitor connected between the filter output terminal and a reference terminal; a bias FET configured to provide a bias voltage to the filter FET; a buffer connected between the filter input terminal and the bias FET, the buffer configured to source a bias current for the bias FET; and an offset voltage source configured to contribute to the bias voltage provided to the filter FET.