A wide range all-digital delay locked loop for video applications

An all-digital delay locked loop (DLL) for use in an analog video front end (AFE) is presented. The DLL is designed for a wide input frequency range of 40-300 MHz to cater to a range of different video standards currently in use. The proposed DLL has a closed loop architecture that tracks PVT variations and locks to the input signal in a maximum of nine clock cycles. At its output, the DLL generates 32 uniformly distributed phases of the input clock to provide an optimal sampling point for the analog to digital conversion of the input signal in the AFE.