A phase detector includes a clock delay circuit, a data delay circuit, a control circuit, a D flip-flop, and a logic circuit. The clock delay circuit delays a clock signal so as to generate a delay clock signal. The data delay circuit delays a data signal so as to generate a delay data signal. The control circuit adjusts the delay time of the clock delay circuit and the delay time of the data delay circuit according to the clock signal and the delay clock signal. The D flip-flop generates a register signal according to the data signal and the clock signal. The logic circuit generates an up control signal and a down control signal according to the data signal, the delay data signal, and the register signal so as to control a charge pump of a CDR (Clock Data Recovery) circuit.

Embodiments of a method that may allow for selectively tuning a delay of individual logic paths within a custom circuit or memory are disclosed. Circuitry may be configured to monitor a voltage level of a power supply coupled to the custom circuit or memory. A delay amount of a delay unit within the custom circuit or memory may be changed in response to a determination that the voltage level of the power supply has changed.