So is BIRD 17 or 18 the same thing?
One more comment I forgot in my last EMAIL:
If anything, I would like to see both clamps have the same range, -Vcc to Vcc,
or even -Vcc to (2 x Vcc). Currently, the POWER clamp is only -Vcc to 0V, and
the GND clamp is -Vcc to Vcc.
We all agreed on earlier open forums that the clamp curves can also be used for
internal pullup or pulldown structures ("resistors") for devices that have it.
These "resistors" are usually weak transistors which are always ON. Since they
are transistors, they have an I-V curve, not a straight resistive line. The
best place to put these in an IBIS model is the clamp curve.
Hovever, currently there is only one place to put such curves, the GND_clamp
curve. This creates a few problems when I have a pullup "resistor" (which I
have to make VCC relative) and I have to put it into the GND_clamp curve. If we
extend the Vcc_clamp range to the same coverage as the GND_clamp, I could put
the pullup "resistors" into the POWER_clamp, and the pulldown "resistors" into
the GND_clamp curve and my problems would be gone.
Arpad Muranyi
Intel Corporation
Received on Mon Jul 25 10:45:20 1994
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