Hi Liviu-Dumitru,
1) a variation of current into pin 9 translates with a factor of Z[2,9]
into a voltage ripple on pin 2
2) the voltage ripple on a pin adds up from self produced current
variations (self impedance) AND current variations on other pins of the
PDN (transfer impedance). So the answer is self and transfer impedances
are significant.
Hope this helps.
Thomas
Am 12.10.2016 um 11:37 schrieb Craciun, Liviu-Dumitru:
Hi all,
for the PDN simulation I placed the Port[1] at the output pin of the VRM
(voltage regulator module)
and
the Port[2], Port[3], ... Port[11] at the IC power pins.
The PDN with only 10 IC power pins is only a simplified example, of course,
in the "real world" there are more IC power pins.
The power integrity simulation software is able to calculate the
self-impedances
Z[1,1] at the VRM
and
Z[2,2], ... Z[11,11] at the IC.
There are the diagonal elements of the impedance matrix.
The elements Z[1,2], Z[1,3], ... Z[1,11] are the trans-impedances between the
VRM and each IC power pin.
In generally, the PDN requirements in the IC data sheet contain only ONE
parameter - Z value @ Freq. -
without to specification "self"- or "trans"-impedance.
MY QUESTIONS:
1) What is the physical significance of the trans-impedance between two
IC power pins ? For example Z[2,9]
2) The IC provider can `t answer the question "what impedance do you
mean, self- or trans-impedance?" The standard answer is "only the impedance".
So the discussion with the IC provider is a "dead end street". I am confuse
... what impedance is significant, self- or trans-impedance ?
Best regards,
Liviu Craciun
Harman Becker Automotive Systems GmbH
Karlsbad, Germany
P.S.
I expected from the IC provider TWO impedances as specifications, self- and
trans-impedance,
But
I received ONLY ONE value. It is unknown if the spec means the self- or the
trans-impedance.
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