forwarding for George..
Reply Separator
Subject:RE: Charge moving from decoupling capacitors
Author: george_t...@dell.com
List-Post: emc-pstc@listserv.ieee.org
Date: 5/23/00 2:19 PM
Barry,
The current can flow from the cap, but it will get to
Forwarded for George..
Reply Separator
Subject:RE: Charge moving from decoupling capacitors
Author: george_t...@dell.com
List-Post: emc-pstc@listserv.ieee.org
Date: 5/23/00 12:35 PM
Let's say that you have a cap placed at 1/4 wavelength
...@silab.eng.sun.com; emc-p...@ieee.org
Subject: RE: Charge moving from decoupling capacitors
George,
I am impressed by your attitude to pursue the correctness, and glad to
discuss with you further on “How does a decoupling capacitor support an IC?”
Here is my two cents worth. The decap supplies necessary
George,
I am impressed by your attitude to pursue the correctness, and glad to discuss
with you further on How does a decoupling capacitor support an IC?
Here is my two cents worth. The decap supplies necessary charge to the IC
during Tr through a transmission line. As you mentioned before:
0 12:31 PM
To: 'Barry Ma'; Tang, George
Cc: si-l...@silab.eng.sun.com; emc-p...@ieee.org
Subject: RE: Charge moving from decoupling capacitors
Barry,
Thanks for the comments. Here are my comments:
Ok, you put caps at a certain distance away from the IC because you only
want the
for George
Reply Separator
Subject:RE: Charge moving from decoupling capacitors
Author: george_t...@dell.com
List-Post: emc-pstc@listserv.ieee.org
Date: 5/22/00 9:14 PM
Barry,
I need to make a correction. I was rushing to lunch on Thursday
s,
George Tang
george_t...@dell.com
-Original Message-
From: Barry Ma [mailto:barry...@altavista.com]
Sent: Thursday, May 18, 2000 10:50 AM
To: george_t...@exchange.dell.com
Cc: si-l...@silab.eng.sun.com; emc-p...@ieee.org
Subject: RE: Charge moving from decoupling capacitors
George,
Thanks for
- Original Message -
From: "Barry Ma"
To:
Cc:
Sent: Friday, May 19, 2000 11:33 AM
Subject: Re: Charge moving from decoupling capacitors
> Ralph,
>
> Please be cautious about what you said below: "the reason why most power
buses on PCBs use several values of decoupling
Ralph,
Please be cautious about what you said below: "the reason why most power buses
on PCBs use several values of decoupling is to ensure that a wide range of
frequencies are covered."
Several V curves shown in the figure of impedance vs. frequency, which we are
all familiar with, would eas
From: "Jim Bacher"
To:
Cc:
Sent: Thursday, May 18, 2000 4:24 PM
Subject: Re:RE: Charge moving from decoupling capacitors
>
> Forwarded for George.
>
> Reply Separator________
> Subject:RE: Charge moving from decoupling capacito
-Original Message-
From: Barry Ma [mailto:barry...@altavista.com]
Sent: Thursday, May 18, 2000 10:50 AM
To: george_t...@exchange.dell.com
Cc: si-l...@silab.eng.sun.com; emc-p...@ieee.org
Subject: RE: Charge moving from decoupling capacitors
George,
Thanks for your long input. I'd like t
George,
Sorry, I forgot to repeat what I wrote to you 5/15/00:
"It is generally acknowledged that decaps and plane cap are complementary
(supposing a 10 mil or less spacing between pwr and gnd planes). Decaps cover
low end of frequency range, while the plane cap takes care of high frequencies."
Forwarded for George.
Reply Separator
Subject:RE: Charge moving from decoupling capacitors
Author: george_t...@dell.com
List-Post: emc-pstc@listserv.ieee.org
Date: 5/18/00 2:30 PM
Barry,
Thanks for the comments. Here are my comments:
Ok
George,
Thanks for your long input. I'd like to make some comments below.
-
On Wed, 17 May 2000, george_t...@dell.com wrote:
> Large parallel plates behave as transmission lines. A quarter wavelength
> transmission line with a short at the end has infinite impedance, so
> capacitors
forwarding for George
Reply Separator
Subject:RE: Charge moving from decoupling capacitors
Author: george_t...@dell.com
List-Post: emc-pstc@listserv.ieee.org
Date: 5/17/00 11:16 PM
Barry,
This is true on most boards. But that is because the
forwarding for George..
Reply Separator
Subject:RE: Charge moving from decoupling capacitors
Author: george_t...@dell.com
List-Post: emc-pstc@listserv.ieee.org
Date: 5/17/00 10:50 PM
You ask an open question, so the open answer to that is &qu
-Original Message-
From: Barry Ma [mailto:barry...@altavista.com]
Sent: Wednesday, May 17, 2000 9:16 AM
To: si-l...@silab.eng.sun.com; EMC-PSTC
Cc: wei...@atdial.net
Subject: Re: Charge moving from decoupling capacitors
Steve,
Thanks a lot for the very nice hierarchy description below
Regards,
George Tang
-Original Message-
From: Barry Ma [mailto:barry...@altavista.com]
Sent: Monday, May 15, 2000 1:33 PM
To: george_t...@exchange.dell.com; si-l...@silab.eng.sun.com
Cc: emc-p...@ieee.org
Subject: RE: Charge moving from decoupling capacitors
Thanks a lot for your inp
Hi Yu,
Lets begin with the excellent description written by Andrew Ingraham:
The voltage sag propagates outward from the chip, consuming charge stored in
the intrinsic capacitance of the planes bit by bit (not all of it at once!),
and eventually reaching external capacitors which help hold u
Steve,
Thanks a lot for the very nice hierarchy description below.
If there's a 10 mil or less spacing between pwr and gnd planes, the plane cap
is available. The plane cap and the decaps are complementary in whole frequency
range. Plane cap takes care of high end, and decaps cover low portio
t; From: Barry Ma [SMTP:barry...@altavista.com]
> Sent: Tuesday, May 16, 2000 4:29 PM
> To: EMC-PSTC; si-l...@silab.eng.sun.com
> Subject: Re: Charge moving from decoupling capacitors
>
>
> Hi Andrew,
>
> You said: "It is just like an ordinary transmission l
Hi Andrew,
You said: "It is just like an ordinary transmission line such as stripline. "
Please allow me to say something different.
(1) When a signal propagates along a transmission line, we could observe a
current loop from source to load through the transmission line. The signal
velocity
nal Message-
> From: Barry Ma [SMTP:barry...@altavista.com]
> Sent: Monday, May 15, 2000 4:33 PM
> To: george_t...@dell.com; si-l...@silab.eng.sun.com
> Cc: emc-p...@ieee.org
> Subject: RE: Charge moving from decoupling capacitors
>
>
> Thanks a lot for your input
A\ndy,
Those are very good answers. Keep up the good work.
Lee
Ingraham, Andrew wrote:
> > As the speed of digital signals gets faster and faster, people begin being
> > concerned with the distance for electric charge to move on power and
> > ground planes of multilayer PCB during the signal r
Thanks a lot for your inputs.
All responses to my second question are only concerned with the inductance due
to long distance between chip and decap. Nobody seems to agree imposing
another constrain to the distance. My question was
Do we really have to limit the distance letting the charge
forwarding for Francis
Reply Separator
Subject:RE: [SI-LIST] : Charge moving from decoupling capacitors
Author: "Kai; Francis"
List-Post: emc-pstc@listserv.ieee.org
Date: 5/12/00 9:02 AM
Dear Electrical Engineers,
Based o
forwarding for Andrew.
Reply Separator
Subject:RE: [SI-LIST] : Charge moving from decoupling capacitors
Author: "Ingraham; Andrew"
List-Post: emc-pstc@listserv.ieee.org
Date: 5/12/00 2:13 PM
> As the speed of digital signals ge
> As the speed of digital signals gets faster and faster, people begin being
> concerned with the distance for electric charge to move on power and
> ground planes of multilayer PCB during the signal rise time from a
> decoupling capacitor (cap) to a chip it serves. I would like to raise two
> ques
TC"
Sent: Friday, May 12, 2000 11:24 AM
Subject: Re[2]: [SI-LIST] : Charge moving from decoupling capacitors
>
> Forwarded for Larry.
>
> Reply Separator____
> Subject:Re: [SI-LIST] : Charge moving from decoupling capacitors
> Autho
avista.com]
Sent: Thursday, May 11, 2000 3:50 PM
To: EMC-PSTC; si-l...@silab.eng.sun.com
Subject: [SI-LIST] : Charge moving from decoupling capacitors
Hi,
As the speed of digital signals gets faster and faster, people begin being
concerned with the distance for electric charge to move on power
Hi, Barry,
Responses below:
At 03:49 PM 5/11/00 -0700, Barry Ma wrote:
>Hi,
>
>As the speed of digital signals gets faster and faster, people begin being
concerned with the distance for electric charge to move on power and ground
planes of multilayer PCB during the signal rise time from a decoupli
Forwarded for Larry.
Reply Separator
Subject:Re: [SI-LIST] : Charge moving from decoupling capacitors
Author: "Larry Miller"
List-Post: emc-pstc@listserv.ieee.org
Date: 5/12/00 7:37 AM
Hi, Barry,
Responses below:
At 03:49 PM 5/1
Barry Ma wrote:
>
> Hi,
>
> As the speed of digital signals gets faster and faster, people begin being
> concerned
> with the distance for electric charge to move on power and ground planes of
> multilayer
> PCB during the signal rise time from a decoupling capacitor (cap) to a chip
> it se
Hi,
As the speed of digital signals gets faster and faster, people begin being
concerned with the distance for electric charge to move on power and ground
planes of multilayer PCB during the signal rise time from a decoupling
capacitor (cap) to a chip it serves. I would like to raise two quest
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