Hello Naveen, If all you need is a unique serial number, you could use something like the= DS2401 from Dallas/Maxim (http://www.maxim-ic.com/quick_view2.cfm/qv_pk/= 2903). They don't come any simpler than that. If you are worried about = frying it, you can put in some further protection in the form of some app= ropriately chosen series resistances. If you need something more, e.g. a bit of extra memory to record more infor= mation, check out some of the other Dallas 1-wire devices, there might be= something suitable. I think there are other companies making similar devices, but the Dallas pa= rt is the one I'm familiar with. They are fairly low cost, too. Since most designers don't like active components on the backplane (for goo= d reason), most designs I've seen (and worked on) uses just a board ID, t= o indicate revisions, by pulling down a few lines to ground. Usually, it= 's enough. Regards, Sandor Daranyi Senior Design Engineer -----Original Message----- From: "Naveen Reddy" <naveenr@xxxxxxxxxxxxxxx> To: <si-list@xxxxxxxxxxxxx> Date: Thu, 16 Oct 2003 11:52:32 -0700 Subject: [SI-LIST] Active components on a highspeed backplane Dear All, Have any of you folks had any designs where you had to place an active component on the backplane? In particular, I need to have a unique 'Board ID' for each backplane and the only feasible solution I can think of is to add a Serial EEPROM; but I am a little weary of this solution because of the risk of 'frying' the chip. Using dedicated pins on connnectors is another possibility, but this is going to require more pins than I can spare. If you have had designs similar to this, I would really like to hear your thoughts on this. Regards Naveen. ------------------------------------------------------------------ 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: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //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