[SI-LIST] Re: Substrate board impedance added to driver impedance for total output impedance of driver
- From: "Ray Anderson" <ray.anderson@xxxxxxxxxx>
- To: <si-list@xxxxxxxxxxxxx>
- Date: Thu, 30 Jun 2005 09:13:51 -0700
Eric-
+------+
--R--L--+---| |
| | Z |
C |driver|
| | |
--------+---| |
+------+
Assuming your RLC package parasitics and Zdriver are connected as in the =
above diagram, vectorially calculate the parallel combo of Zc and =
Zdriver and then add that value (vectorially) to the vector sum of Zr + =
Zl. Or put the circuit into spice and let it do the number cunching for =
you.
Zinput =3D Zr + Zl +(Zc // Zdriver)
-Ray
Raymond Anderson
Senior Signal Integrity Staff Engineer
Product Technology Department
Advanced Package R&D
Xilinx Inc.
=20
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] =
On Behalf Of Eric Steimle
Sent: Thursday, June 30, 2005 7:59 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Substrate board impedance added to driver impedance =
for total output impedance of driver
I'm have a chip that I've done some analysis on to get its driver
impedance. However this chip is on a substrate board, and it's drivers
run through traces to balls and to the board. I have R, L, and C
numbers for the trace/bondwire combination as part of a package model
that was made by someone else. The trace in question is =BD inch long =
and
the frequency of interest is 350Mhz. I've made the assumption that I
can use vector addition to add the inductive and resistive contributions
together, but I don't know what to do with the capacitive part. I'm
also assuming that once I've vector added the inductive, resistive, and
capacitive parts together for a total Zpackage that I can then linearly
add Zpackage and the Zdriver from previous experiments. Does that seem
right? I'm just a little confused on the appropriate steps to take. As
always I appreciate the time you all take to read and respond to my
questions.
=20
Thanks,
=20
Eric Steimle
=20
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=20
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