[ibis-macro] Re: What is "Local Ground", how are all voltage measurements made

  • From: Mike Steinberger <msteinb@xxxxxxxxxx>
  • To: ibis-macro@xxxxxxxxxxxxx
  • Date: Tue, 17 Jan 2017 17:03:40 -0500

All-

To quote Heidi Barnes (and possibly others) "ground" is for potatoes and carrots.

Rather than referring to "Local Ground", I request that you refer to a "local return node" as a single point on the current return path for a given circuit node. Even this concept is an engineering approximation; however this approximation can at least be rigorously defined. Given a signal node and its corresponding local return node, the only voltage that is defined is the voltage difference between the signal node and the local return node; and that's enough information to solve even a complex high frequency circuit. Tautologically speaking, it is true that the voltage difference between the local return node and itself is 0.0V; however, that isn't a very useful observation.

Mike Steinberger

On 1/17/2017 4:13 PM, Walter Katz wrote:


All,

I think that IBIS should simply state:

All voltage measurements at a buffer shall be made relative to a “Local Ground” node.

The “Local Ground” is defined as any Rail Terminal that has a value of 0.0 volts in DUT conditions.

·If there is no Rail Terminal that has a value of 0.0 volts in DUT conditions, then

oA component pin rail signal name that has a 0.0V DUT value, then that signal name shall be “Local Ground”.

§If there is no component pin that has a DUT value of 0.0V, then simulator Node 0 shall be the reference voltage for all voltage measurements.

Walter

Walter Katz

wkatz@xxxxxxxxxx <mailto:wkatz@xxxxxxxxxx>

Phone 303.449-2308

Mobile 303.335-6156


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