Replies embedded below At 01:56 PM 9/8/2010, Shahbaz Assad wrote: >Hi Experts, > >What does it means by power plane impedance while doing Power >Integrity analysis. > >The power plane impedance is kept at mili ohms for a wide range of >frequencies for better PI. > >Kindly guide me > >1. what does it means by power plane impedance? The impedance seen >by the IC Chip between the Vcc adn GND planes, to put it in a simple >(but not exactly true) way. >2. what should be its nominal value? As low as possible, ideally 0 ohms >3. For better PI, should its value be as small as possible like >2mOhms? Yes. Theoretically consider wires connected to the vcc and >gnd pins of a chip which have 0 inductance and 0 resistance. That >would be an ideal case with 0 power plane impedance. But >unfortunately this never happens in real life. >4. if yes? what is the reason. One issue in power plane is >resonance. All conductors comprise R,L,c. With any RLC comes >resonance frequencies. The impedance of circuits changes >dramatically at resonance frequencies. For example an ideal C and L >in series has zero impedance at resonance frequency and an ideal C >and L in parallel has infinite impedance at resonance >frequency. Effectively, at resonance frequency the power plane >presents a high impedance to the chip so current will not flow in >easily as needed at that frequency. > > >Thanks In advance. I am new to SI and PI > > >Thanks, >Shahbaz Assad > >System design Engineer - WhizzSystems, Inc. > >_____________________________________ >Skypes ID: sassad85 | >sassad@xxxxxxxxxxxxxxxx > > > > > > > > > > > >------------------------------------------------------------------ >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 technical documents are available at: > http://www.si-list.net > >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 > ------------------------------------------------------------------ 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 technical documents are available at: http://www.si-list.net 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