Glen, within a chassis Ethernet magnetics are generally overkill. Ethernet can be DC isolated with capacitors instead of magnetics provided that the PHY expects 1:1 turns ratio, and you bias properly. If the PHY expects a different ratio, then you need to take steps to match the impedance. You will also have loss, but that shouldn't be a problem inside a box. This likely doesn't apply to you, but for POE you absolutely need magnetics. Going out of chassis is another matter. You will be hard pressed to find a capacitor arrangement that can meet the 802.3 specs at any price. Steve. At 01:50 AM 2/26/2006, glenchen@xxxxxxxxxxxxx wrote: >Hi , all members of si-list , > In ethernet connection , we use transformer for DC blocking . While >in audio applications or other high speed links , we use capacit for DC >blocking . >Can we use capacitor for DC blocking in ethernet connection ? Why ? What >is the difference between using transformer and using capacitor for DC >blocking ? > I am very appreciated if anyone can give me the answer . > >- Glen Chen > SynerChip Tech . > >------------------------------------------------------------------ >To unsubscribe from si-list: >si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field > >or to administer your membership from a web page, go to: >http://www.freelists.org/webpage/si-list > >For help: >si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > >List FAQ wiki page is located at: > http://si-list.org/wiki/wiki.pl?Si-List_FAQ > >List technical documents are available at: > http://www.si-list.org > >List archives are viewable at: > http://www.freelists.org/archives/si-list >or at our remote archives: > http://groups.yahoo.com/group/si-list/messages >Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: http://www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: http://www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu