A phase detector biased in a manner to alleviate the mismatch between the biasing current sources and the phase detector core bias currents. The bias setting resistors are coupled together at a common node that forms the negative input of a differential feedback amplifier. The positive input to the amplifier is referenced to a reference voltage, and the output of the amplifier controls the biasing current sources. The feedback amplifier forces the average voltage at the current source outputs to approximately match the reference voltage applied to its positive input. Thus the average bias current from the bias current sources is forced to track the average bias currents of the phase detector core.
