Your formula is for instantaneous stored energy in a capacitor, not power. Power is the time rate of energy flow, which requires integration to solve for. This results in disappearance of the factor of 1/2 and an answer that involves V rather than V^2. When Eric's formula divides the V^2 in the numerator by P (= VI), that is what you get. Orin -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Amit KUMAR STE Sent: Friday, August 05, 2011 3:44 AM To: si-list-request@xxxxxxxxxxxxx; si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Power dissipated in a chip Hello Experts , Sorry if I sound naïve. According to Eric Bogatin's SI book , the time until the voltage droop increases to 5% of the supply voltage , because of the decoupling capacitance is : t=(C*0.05*(V^2))/P where P is the average power dissipation of the chip. C is the decoupling capacitance between the power plane and ground plane. How do we get this forumula for the time taken in voltage droop? The power forumula I know is P=1/2 CV^2 . Please give me some reference from where I can understand this . Thanks and Regards Amit ------------------------------------------------------------------ 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