Hi Paul, I'm one of those people who probably uses the words interchangeable.
To me, 'bypass' brings to mind *shunting* something to another place, like bypassing IC-generated noise to circuit common, or bypassing circuit noise to chassis. 'Decoupling' makes me think of *separating* two parts of a circuit, like decoupling noise from an IC from getting to the power bus, or preventing power bus noise from reaching an IC. For a component that addresses control loop stability issues, I typically use the word 'compensation'. If you want a more focused audience, consider subscribing to the 'si-list', which deals with signal integrity problems. One web link that looks current is http://www.freelists.org/archives/si-list/ Pat Lawler EMC Engineer SL Power Electronics Corp. [email protected] wrote on 04/16/2008 08:41:03 AM: > Not sure if this is the right post to ask this question > but feedback would be appreciated. > > Can anyone provide me with the difference between a bypass and > decoupling capacitor? My understanding is that bypass caps are used > for stabilizing a power supply, and would be used to provide low end > AC filtering on a power supply up to a couple hundred MHz and they > could be located from the power supply output to being scattered > through a board to stabilize the power distribution system and > normally have higher than .1uF cap values. Also, decoupling caps > would be used local to the ICs on the PCB and provide high frequency > noise coupling as well as provide some local power stabilization for > the switching noise that will occur due to the high frequency > switching of the transistors in the IC. > > When I looked online for these definitions, it seems > like some people are using these terms interchangeably. It may just > be semantics, but I am looking for some confirmations from people > with a bit more experience on this subject. > > Thanks in advance for your help. > Paul Denomme <remainder of post removed> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
