Rahul, It is not considered as over design it is about achieving optimum design sizing. Something similar to location of operating point in a transistor amplifier circuit. The main factors are to optimize the efficiency, heating power, operating individual devices at their safe limits at all i/p power and o/p power at all ambient temperature, and minimize the RF emission as well. All these optimization leads to better MTBF. The over design happens when you don't know the optimum level of the requirement or optimum level of critical devices. I hope you will spend some good time in the public domain ///lr to http://www.xppower.com/pdfs/techguide.pdf Thanks Sen ------------------------------------------------------------------ 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 forum is accessible at: http://tech.groups.yahoo.com/group/si-list List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu