Method and apparatus for clock uncertainty minimization
AssigneeCisco Technology, Inc.
InventorSergio D. Camerlo
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AssigneeCisco Technology, Inc.
InventorSergio D. Camerlo
Estimating the term…
A method and apparatus for drastically reducing timing uncertainties in clocked digital circuits simply, at virtually no cost, and using only standard clock drivers and simple, inexpensive electrical components is described. The method includes the steps of minimizing timing uncertainties by controlling both clock skew and clock jitter. Intrinsic clock skew is eliminated by ganging the outputs of a multi-line clock together onto a capacitive metal island disposed on a printed circuit board (PCB). Extrinsic clock skew is controlled through the use of wide, relatively high-capacitance traces of matched length and disposed on a single, common signal layer of the PCB, each leading to a respective receiver circuit and terminated identically. Clock jitter is controlled by electrically isolating a region of the PCB, disposing the clock driver in the region in such a way as to minimize noise, and providing quiet local power and ground to the region.
A method of minimizing clock uncertainty in a digital circuit, comprising a multi-line clock driver and a plurality of clocked circuits, linked to said clock driver with conductance traces of a printed circuit board, said method comprising:
An ultra-low skew clock tree disposed on a printed circuit board and driving a plurality of clocked circuits, said clock tree comprising:
Dependencies are inferred from the claim text.