Described is an apparatus which comprises: a current source to generate a current having AC and DC components； a current-to-voltage converter to convert the current or a copy of the current to a voltage proportional to a resistance, the voltage having AC and DC components that correspond to the AC and DC components of the current； a first sample-and-hold circuit to sample and filter the AC component from the voltage and to provide an output voltage with the DC component； a second sample-and-hold circuit to sample the output voltage； a voltage-to-current converter to convert the sampled output voltage to a corresponding current； and an amplifier to receive the output voltage.
