Rohit, Both Murata and TDK have free tools which provide equivalent circuit and S-param models for most of their general purpose MLCC. Murata: http://www.murata.com/products/design_support/index.html TDK: http://www.tdk.com/seat.php Mike ________________________________________ From: si-list-bounce@xxxxxxxxxxxxx [si-list-bounce@xxxxxxxxxxxxx] On Behalf Of steve weir [weirsi@xxxxxxxxxx] Sent: Tuesday, January 17, 2012 11:01 AM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: S-parameter of dcap It all depends on what level of accuracy that you want / need, and what tools you are using. There are cap manufacturers who supply S parameter models. Depending on the tool you are using, S parameters may or may not be what you want. One tool from a major vendor will only deal with a single L-R-C model. Modeling a PDN without considering inductance saves a lot of time. It eliminates the need for bypass capacitors altogether. I highly recommend it for designs with di/dt's below 1A/s. Steve. On 1/17/2012 6:59 AM, Rohit MISHRA wrote: > Friends, > I am stuck in a problem so thought it would be better to take assistance from > all you experts there :) > > Actually we need to extract s-sparameter of PDN network of one USB board. > Board database(.brd) which we have got has all dcaps included and If I check > capacitance model in database, it has just capacitance value but has no ESR& > ESL mentioned. > > I have tried to find s-parameter of these MLCC dcaps so that I can add them > in PDN extraction but my bad luck :( all I have got is SRF& ESR. > > Now my question is : > > > 1) Do we really need to have s-parameter of dcap for accurate PDN > extraction ? > > 2) If I use dcap spice model instead, do we really need to have ESL in > that model. Can't we use just ESR& C in spice model ? > My argument is that ESL of dcap which is mentioned in datasheet or one which > we can calculate from SRF& capacitance is basically intrinsic/self > inductance of capacitance lead which in MLCC case will always be much lower > than mounting& spreading inductance So we shouldn't worry much about ESL of > dcap while extracting PDN network. > > Do you see any problem in this argument ? > > Rgds, > Rohit > > > > ------------------------------------------------------------------ > 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 > > > -- Steve Weir IPBLOX, LLC 150 N. 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