With a 3.3V driver, the 178 ohm parallel term appears to produce a ~2.5V swing at the receiver. Maybe the receiver is a 2.5V part. Maybe they were trying to trim the duty cycle. For the perfectionist, the series term may have to be 55-2*7=41 ohm instead of 36 ohm. Thanks, Vinu Lucas Bossetti wrote: > Hi all, > In the schematic of an evaluation board I've seen some clock nets like that: > > > parallel term to gnd R=178 ohm > > | > > | > |---SERIES TERM 36ohm----Tline 55 > ohm------|----RECEIVER > DRIVER 7 ohm--------| > | --SERIES TERM 36ohm-----Tline 55 > ohm------|---RECEIVER > > | > > | > > parallel term to gnd R=178 ohm > > Can someone explain me why the value of the parallel term is 178 ohm? > Any comment will be appreciate. > > Thanks in advance > Lucas > > ------------------------------------------------------------------ > 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 > ------------------------------------------------------------------ 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