re: the range of the voltage.

Vincent,
in addition to the replies made from other IBIS folks, please be
aware of the fact that recent generation 3.3V bus logic don't have
VCC clamp diodes on their I/O's to allow 3V/5V mixed logic on
one system. Also those devices that 3-state their outputs when
VCC=GND (to allow power down of parts of a system connected to a
common bus) don't have these diodes. So it's worth to have a look
at up to +2VCC on those devices.

Hans M Hilbig
*************************************************
EMSLP Characterization Texas Instruments Freising
Phone: +49-8161-804126 FAX:+49-8161-804909
e-mail: h-hilbig@ti.com

------------------
Original text

From: Vincent Chang <vchang@memh.ti.com>, on 7/3/97 3:59 PM:
Hi all,

Sorry, I did not make myself very clearly in the last message.

Let's try again.

The first question is Why should we
do simulation from -Vcc to 2Vcc if we have diodes for
clamping the output to Vcc and Gnd ? Is it not true that on
an actual PCB, even if the voltage at any pin tends to go
higher than Vcc (due to L-C effects etc.), the clamping
diodes will allow it to go only till Vcc+Vf, where Vf is the
forward voltage of the clamping diode? Basically that's
what the diodes are for.

The second question is,
Can I use the voltage range from -Vcc to 1/2Vcc for Gnd Clamp?
Is QC check going to fail on that voltage range?

-- 
Best Regards,
			Vincent Chang
			
=======================================================================
*  Vincent Chang                         TI MSG ID: hui8              *
*  Design Automation                     mailto:vchang@memh.ti.com    *
*  Memory Products Design                http://www.memh.ti.com/~mcad *
*  Texas Instruments Inc. MS 657         Phone: (281) 274-3167        *
*  PO Box 1443, Houston, TX 77251        Fax:   (281) 274-2067        *
=======================================================================