 
| Received: |
by ipc.org (Smail3.1.28.1 #2)
id m0vhF5a-0000UOC; Mon, 6 Jan 97 07:27 CST |
| Content-Type: |
text/plain; charset=US-ASCII |
| Old-Return-Path: |
|
| Date: |
Mon, 6 Jan 1997 08:39:57 -0500 |
| Precedence: |
list |
| Resent-From: |
|
| Resent-Sender: |
|
| Content-Transfer-Encoding: |
7bit |
| Status: |
O |
| X-Mailing-List: |
|
| TO: |
|
| Return-Path: |
<TechNet-request> |
| X-Status: |
|
| X-Loop: |
|
| Content-Description: |
cc:Mail note part |
| Subject: |
|
| From: |
|
| Mime-Version: |
1.0 |
| From [log in to unmask] Mon Jan 6 10: |
36:26 1997 |
| Resent-Message-ID: |
<"fClQM2.0.cO9.DtFqo"@ipc> |
| Message-Id: |
|
| Parts/Attachments: |
|
|
Thanks for the clarification.
______________________________ Reply Separator _________________________________
>I'm not sure I understand your concern about the impedance
>"between" a pair of traces. Each trace has its own impedance. For a
>differential pair, you would need to match those impedances, as
>well as other characteristics such as delay.
>No it does not matter if one plane is "hot" and the other is ground.
>That is a DC definition. At high frequency, the power plane is just
>another ground plane, and is an additional path for a high-speed
>return signal. The capacitance between the planes does provide some
>lead inductance decoupling
> Does anyone out there have the preferred configuration and equations
>for controlling the impedance between a differential pair of traces
>that are sandwiched between two power planes on epoxy-glass?
>
> Also, does it matter if one of the power planes is ground and the
>other "hot", or will the inevitable in-circuit capacitance between them
>ensure a common ac reference at typical transmission line frequencies?
>
Max.P.Harris
Lockheed Martin Canada, Inc.
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To unsubscribe from this list at any time, send a message to: *
* [log in to unmask] with <subject: unsubscribe> and no text. *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] *
***************************************************************************
|
|
|
