Agreed, Mike.
Return node
Reference node
Anything but Ground
Scott McMorrow, CTO Signal Integrity Group
Samtec
Office 401-284-1827 | +1-800-726-8329
www.samtec.com<http://www.samtec.com/>
From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] ;
On Behalf Of Mike Steinberger
Sent: Tuesday, January 17, 2017 5:04 PM
To: ibis-macro@xxxxxxxxxxxxx
Subject: [ibis-macro] Re: What is "Local Ground", how are all voltage
measurements made
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
o A 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
