A voltage controlled oscillator (VCO) core for cancelling a supply noise is described. The VCO core includes an input node that receives the supply noise. The VCO core also includes a noise path coupled to the input node. The VCO core additionally includes a cancellation path coupled to the input node and the noise path. The cancellation path includes a programmable gain circuit coupled with a first terminal of a varactor. The supply noise passes through the programmable gain circuit to produce a cancellation noise.