to control the delay between the input signal in and the output signal out for example increasing the tail current i makes the effective load resistance r m reduced by the swing fixing circuit 102 to maintain the fixed voltage swing v sw which in turn reduces the delay time hence transistors m 11 m 5 and m 6 function as tail current sources and provide the ability to coarsely and or finely adjust the differences between signals the hybrid vcd 100 employs the advantages of both the current starved method and the phase interpolation method the vcd or vco includes two control inputs vcrs and vfine one for coarse tuning control and the other for fine tuning control respectively coarse tuning control is done by the current starved method to provide a wide tuning range over process and temperature variations while the phase interpolation method is used to offer a linear tuning curve and low jitter performance use of the current starved method with active pfet loads e g m 7 m 8 m 12 and m 13 instead of resistor loads enables implementing nested current starved vcd within the phase interpolated delay element in this way the current starved vcd within phase interpolated delay can track phase variation with large tail current variation using variable current source 106 also the hybrid vcd topology can be further extended to build composite voltage controlled delay lines vcdls using both current starved vcd and hybrid vcd having similar kinds of active pfet loads the.