sample / hold times

re: usefull timing data.

Quad Design manufactures two main products, A transmission line
simulation tool (XNS) and a static timing verification tool (MOTIVE).
We have been in the business for about 7 years now of supplying 1) SI
information and 2) timing data. We have found that the information you
need in the SI tool inorder to provide usefull information to the
Timing tool are: Input Thresholds and VM delay correction.

The rest of the timing data is needed by the Timing tool but is not used in
any context by the SI tool, while the SI tool CANNOT PROVIDE ADEQUATE
data to the TIMING tool without information about input logic
thresholds.

my point, Input thresholds are necessary for SI models to be able to
provide the required pin-to-pin delay data to Timing.

VM correction is a really sticky wickett. This involves correcting for
the manner that the manufacturer measured and specified internal part
delay (usually driving a 50pf load). It is a nice thing to have but
can usually be approximated or calculated on the fly by the SI tool.

regards,

jon
Received on Wed Mar 16 11:18:33 1994