What are the advantages of the DLL over the traditional PLL?
Compared to a phase locked loop (PLL), a DLL has a number of advantages. The Virtex-E DLL is a complete digital implementation that simplifies the processing and the future scalability of the DLL. The Virtex-E DLL does not accumulate jitter because each clock edge in essence restarts the circuitry. Further, the Virtex-E DLL has been proven to operate at frequencies over 311 MHz while competing PLL solutions in programmable logic devices either had questionable success or are limited to frequencies below 100 MHz. Unlike the PLL solution, the Virtex-E DLL also does not require external inductors, capacitors, or separate ground and power plane when implemented in a system design.
