Subject: EGG Half Dozen

From: [email-masked] (Jon Powell)
Date: Thu, 10 Aug 95 10:09:52 PDT

More Argument on EGG Half Dozen.

Hopefully by now people have the hardcopy in hand and can look at
the two IV curve groups. If we have no argument on how they look
(at least, in general appearance) then my problem is this:

As the "control" voltage changes on the CMOS gate only the IV curve
strength changes. The zero millamp point stays constant (at ~VCC) this
makes sense as all we are doing is making the CMOS gate more resistive.

The TTL gate, however, changes its zero milliamp point, it being a totem
pole arrangement and all. 

The point is, at risetime/2, what is the proper thevinin equivalent for the
driver? You have to know if it is CMOS or TTL. If there is a fool proof way
to determine this form the IV curve alone, they we are done, else I would
like a new (optional?) KEYWORD.

regards,
jon

(I hope I got this HALF-DOZEN joke out before bob or will).

(If you still need hardcopy, let me know. Won't it be nice when I can just
post HTML to a WWW EGG discussion page?).

---

From: Arpad Muranyi <[email-masked]>
Date: Thu, 17 Aug 95 16:46:00 PDT

Text item: 

Jon,

I have an idea that might do the thing without an extra keyword.  (I didn't 
spend much time on this, though, so I am not sure if this is fool proof).

The I-V curves of bipolar pulldown structures usually cross the voltage axis 
above 0 volt, in other words, zero current is at approximately 0.15 V on those 
I-V curves.  On the other hand, the I-V curves of CMOS pulldowns would go 
through the origin, since the channel behaves more like a voltage controlled 
resistor (i.e. no voltage, no current).  If the I-V curve in an IBIS file is 
accurate enough to detect this difference, I think you can just look for the 
voltage at zero current, and if it is not zero, you could assume a bipolar 
device.

Do you think this will work?

Arpad
===============================================================================
More Argument on EGG Half Dozen.

regards,
jon

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Subject: EGG Half Dozen
To: [email-masked]
From: [email-masked] (Jon Powell)
Date: Thu, 10 Aug 95 10:09:52 PDT
:39:38 -0700
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