Khalid Ansari wrote: > >I just have enough space to place this one close to the pin, the rest have >to go quite further away due to space constraint. Placing them too far >away I have to worry about the loop inductance. > The loop inductance you need to be concerned with is that of the loop formed by the decap, the mounting pads, vias and power planes. The distance between the decap and the IC doesn't determine the loop inductance. That being said, the distance IS an issue when you consider the time of flight between the decap and the IC consuming the current. A commonly used rule-of-thumb is that the decap should be within 1/10 wavelength (at the frequency of interest) of the chip it is supplying in order to be effective. If you are too far away, the chip requiring the current may not get it in time from the decap sourcing the current. -Ray Anderson Sun Microsystems Inc. ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field 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