[SI-LIST] Re: Power plane resonace for multi-plane issues
- From: =?big5?b?Sm9obiBMaW4gKKpMtMK31yk=?= <John@xxxxxxxxxxxx>
- To: <si-list@xxxxxxxxxxxxx>
- Date: Thu, 3 Jun 2004 09:19:19 +0800
My special thanks to Sogo, who was my instructor in using SpeedXP =
several years ago.
He pointed out that I used 4 resistors (0.1 ohms) to short VRM to form a =
current loop in my simulation. For measurement, I used 4 wires to short =
VRM to mimic the 0.1 ohms. It was wrong. I should also use wires to =
short VRM in my simulation to match the simulation with measurement.
He is right. Now the correlation looks much better..
I appreciate his helps... Thanks again
John
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx
[mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of John Lin =
(=AAL=B4=C2=B7=D7)
Sent: Wednesday, June 02, 2004 2:15 PM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Power plane resonace for multi-plane issues
Dear all SI gurus,
one question regarding Power plane resonance.=20
Currently, I use SpeedXP from Sigrity for simulating power plane =
resonance. =20
The set up is that
TOP layer : VCCP ----- on top layer,
2nd layer : GND, VCC3_3 -- partially overlap both =
plane on the second layer
3rd layer : GND =20
....
BOT layer: VCCP -- on bottom layer
I inject a current pulse into VCCP at a node on the top layer. With =
Fourier transfer for voltage and current, and got a plot of plane =
impedance. My VNA measurement shows a resonance at 50 Mhz, but the =
simulation show 100Mhz. =20
I think the mismatch may be among , VCCP,VCC3_3, and GND plane . Shall =
I let VCC3_3 plane float or tie it to somewhere?
I know Cadence's PI tool need to specified each overlapping plane pairs =
with correct voltage difference for multi-plane issues.
I don't know how to take care current injection issues on Sigrity =
SpeedXP for multi-planes.
Does somebody please kindly shed some light on it.
Thanks,
John =20
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=20
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