Benny, I know my question is so basic and seems to be ridiculous. What I interest is how to get the current profile for voltage noise simulation associated with PDN, for it is hard to get the current = profile of ICs in the power rail from IC supplier. Though there's a method to get current profile by voltage tests = indirectly, I'm still interested in getting it by direct tests. So I ponder upon the problem whether it exits a path I can test simply = and accurately? Zhengrong -----=D3=CA=BC=FE=D4=AD=BC=FE----- =B7=A2=BC=FE=C8=CB: Benny Yan [mailto:zyan@xxxxxxxxxx]=20 =B7=A2=CB=CD=CA=B1=BC=E4: 2007=C4=EA8=D4=C230=C8=D5 21:20 =CA=D5=BC=FE=C8=CB: xuzhengrong@xxxxxxxxxx; si-list@xxxxxxxxxxxxx =D6=F7=CC=E2: RE: [SI-LIST] the difference of current profile between = power supply path, signal path and return path in a circuit loop Forgot Kirchhoff's current law? =20 Benny Yan IO Methodology Inc.=20 -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] = On Behalf Of xuzhengrong Sent: Thursday, August 30, 2007 8:34 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] the difference of current profile between power = supply path, signal path and return path in a circuit loop Hi all, After scanning the discussion about the return path, I have to think = such a question that, what does the current profile in power supply, signal = path and return path in a circuit loop look like, and what is the difference = of the three ones? As is known to all, in a simple DC circuit such as small bulb loop, = current supply is equal to the return current between possive pole and negative pole. Then, in a high speed digital circuit, if only one buffer works and = outputs one signal level(excluding multi-signal use the common return path and = power supply path ), would current profiles in the signal path and its return = path be the same? Furthermore, as the source of the signal current, what is the = difference between the current profile in the power supply path and its signal = current profile? Thanks for any idea. Zhengrong ------------------------------------------------------------------ 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 technical documents are available at: http://www.si-list.net List archives are viewable at: =20 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 =20 ------------------------------------------------------------------ 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 technical documents are available at: http://www.si-list.net 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