Vinod, what they are really saying is that below a cut-off frequency the supply can vary by +/-4% and above it the supply can only vary by +/-2%. If you think about generic PSRR rejection, you will see that it can be very high at low frequencies, and degrades at higher frequencies. Steve. On 5/23/2013 10:01 PM, vinod ah wrote: > Hi All, > Have a very basic question on AC DC spec provided to power pins of an > ASIC/IO Controller. > > I am working on PLL Characterisation and i find that supply voltage for > that PLL is from an Pin which is 1.2V powered. AC spec is +-2% while DC > spec is +-4%. > > I assume that AC spec means ripple while DC spec means supply voltage > tolerance (not ripple). > > So was wondering how is the AC DC spec derived in the first place? > > Regards > Vinod A H > > > ------------------------------------------------------------------ > 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 > > > -- Steve Weir IPBLOX, LLC 1580 Grand Point Way MS 34689 Reno, NV 89523-9998 www.ipblox.com (775) 299-4236 Business (866) 675-4630 Toll-free (707) 780-1951 Fax All contents Copyright (c)2013 IPBLOX, LLC. All Rights Reserved. This e-mail may contain confidential material. If you are not the intended recipient, please destroy all records and notify the sender. ------------------------------------------------------------------ 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