A delay line circuit is provided and includes a plurality of delay units configured to receive an input signal and to provide a first output signal. The plurality of delay units is configured to selectively invert or relay the input signal to produce the first output signal based on a first instruction received from a delay line controller. A phase interpolator unit includes an offset unit configured to selectively add a speed control unit in the phase interpolator unit based on a second instruction received from the delay line controller. The phase interpolator unit is further configured to receive the first output signal and provide a second output signal. An operating method of the delay line circuit is also provided.