Re: fwd: Re: [SI-LIST] : Does IBIS describe output transition which both

A. D. Shirpadaraj (ads@cadence.com)
Wed, 13 May 1998 13:29:49 +0531 (IST)

Hi Jean,

V-T curve implicitly contains the behaviour of a buffer
during transition. If you want to know the magnitude of
current passing through the transistors during transition,
then it may not be possible from IBIS data directly.

^ VDD
|
___|
|------|
| |__
| |
-- ----| |-------0-----/\/\/\-----0VREF
\ | | |
\___ | ___| |
-----o| -----
|__ -----
| |
| |
--------0
___|___
_____
_

During transition current being drawn(or sunk) from Vref
varies continously, which will be reflected in the output waveform.
So in that way V-T curve does capture transition behaviour of a buffer.

If you have more than one V-T curve, the transition can be modelled
more accurately.

Thanks

Shripadaraj
Cadence Design Systems
NOIDA
India

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