Re: [SI-LIST] : RE: [SI-LIST]: Long bus or star?

D. C. Sessions ([email protected])
Mon, 29 Mar 1999 16:58:50 -0700

Shayle Hirschman wrote:
> DC Sessions wrote>
> >Assuming that you can still find something that slow, or can
> >have one custom-designed (not cheap -- I know whereof I speak
> >since custom I/O design is what I do here....)
> >
> >Lacking a supply of 74LS devices or a budget for full-custom
> >silicon, you're pretty much stuck with the native edge rates
> >for standard silicon. Assuming that your product is behind
> >the curve but not too far (say 350-500nm technology, the
> >stuff that likes 3.3v) then you can figure on worst-case (slow)
> >edge rates in the 300-600ps range and fast-case ones about
> >60% of that.
> >
> >IOW, 300ps or faster.

> How far behind the curve is ABT and even BCT technology? I think edge rates
> of 2 ns are quite relevant to many people's work. Avoiding edge rates in
> the psec range is sometimes a good idea, and can be done so without LS
> devices.

IIRC they're somewhere near 500nm.
Then again, they don't have 2000ps edges, either.
Have a look at their IBIS V/T curves and see what I mean.

> Does anyone remember a family by, I think National, called Damn Fast?

That *has* been a while! (They were comparators and
sense amps, back when there actually were "sense amps" you
could get without the memory array attached.)

D. C. Sessions
[email protected]

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