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PCI-X I/O pads
I am currently involved in developing a PCI-X chip.
The problem I am facing
is meeting the Output Valid time of 3.8ns as
specified by the PCI-X
specification. The signal from the core logic is
registered and it passes
through two buffers and then the PCI-X I/O pad. The
delay in this path is
clock-to-Q of flop ( 0.6),Buffer delay (0.6ns), the
PCI-X I/O pad delay ( 2.3ns )
and a clock insertion delay (0.5ns ). With this
amount of delay it is not possible
to meet the output valid time of 3.8ns.
would appreciate if somebody can provide some idea on how this timing
3.8ns can be achieved if the PCI-X I/O pad delay itself is around 2.5ns ?
Are you aware
of any technology library that has PCI-X
I/O pads with less than 2.0ns output delay so that
this timing can be achieved ?
advance for your help,