[SI-LIST] : RE: Charge moving from decoupling capacitors

...@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

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 charge to the IC during Tr through a transmission line. As you mentioned before:

RE: Charge moving from decoupling capacitors

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 them to work at 100 MHz

[SI-LIST] : RE: Charge moving from decoupling capacitors

-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

Re: Charge moving from decoupling capacitors

Message - From: Barry Ma barry...@altavista.com To: ral...@igs.net Cc: emc-p...@ieee.org 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

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 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

RE: Charge moving from decoupling capacitors

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.

[SI-LIST] : RE: Charge moving from decoupling capacitors

- 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 to make some comments

RE: Charge moving from decoupling capacitors

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

[SI-LIST] : RE: Charge moving from decoupling capacitors

-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

[SI-LIST] : RE: Charge moving from decoupling capacitors

-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 inputs. All responses to my

Re: Charge moving from decoupling capacitors

Hi Yu, Let’s 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

Re: Charge moving from decoupling capacitors

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

RE: Charge moving from decoupling capacitors

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 line such as stripline. Please allow me to say something different. (1) When a signal propagates along a transmission

Re: Charge moving from decoupling capacitors

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

RE: Charge moving from decoupling capacitors

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

Re: Charge moving from decoupling capacitors

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 serves.