How is it even possible to "design" a PDN when IC manufacturers do not provide any information about the power characteristics of their parts such and current draw vs. frequency. There are no models as to what is inside the ICs at the power pins. So all the design tools in the world are not going to solve that problem. It seems that IC manufacturers could provide this information if they had the motivation to do so. Joel -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Istvan Novak Sent: Saturday, February 07, 2009 4:10 PM To: Aleksandr Oysgelt Cc: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: What are power integrity tools available out there? Anything inexpensive that works? Aleks, You raise valid and good questions, but I am afraid the answers may not make you happy. If you look around the tool market, there are several good commercial tools on the market; you named two of them, and we can add some more, for instance the Ansoft/Ansys SiWave and Cadence PI tools. These are the most sophisticated publicly available tools at the moment, and even these wont give you a design. Some tools have optimization features built in, but one could argue that the outcome of the optimization depends largely on the initial constraints you put in, so unless the user has some idea of what is going on, it wont tell you what to do, it just tells you the performance of the design you have come up with (or within the constraints you set in the optimizer). It would be great to have both pre and post layout simulation capabilities in the same package at a low cost. When you look at the commercial tools, you will find that they are all better or more convenient only in one or the other. To get the cost down and get you something beyond lumped spreadsheet and rectangular-plane cavity-resonance formulas, your best bet is to look around among pre-layout tools. For instance, you might want to try EZ PowerPlane from http://www.ems-plus.com/ezpowerplane.html. When it comes to DC drop, you can do what-ifs with a pre-layout tool, but you really want and need a post-layout check, because pre-layout tools will not easily capture all the fine details (via antipad dimensions, via barrel resistance) that you eventually need for a reasonable answer. We know that there are less demanding and more demanding designs in terms of how much work you may need to put into the power distribution network design to get a satisfactory product. If you deal with the category where you can stay competitive only if you squeeze out every drop of extra fat from your system, the possible alternatives are: either you outsource this aspect of the design (and beyond cost, this solution has its own extra challenges), or the company gradually gains the knowledge and expertise (and the necessary tools) to handle these tasks. So in this respect I view the last wish-list item as not being compatible with the rest of the list items. And finally, when you go through the exercise of obtaining the suitable tools and playing with them and a few designs have been completed successfully, you may find that you do not need the tools for certain tasks, because you already gained the knowledge so that you know what to do without simulations. I hope this helps. Regards, Istvan Novak SUN Microsystems Aleksandr Oysgelt wrote: > I am starting to look at power integrity tools and would like to know what > is available and whether there are any "slimmed down" versions that can do > what I need at lower price than full-blown Sigrity-like packages. > Currently we use "spreadsheet" approach where we analytically compute plane > impedance based on self+mounting impedances of various types of caps plus > plane impedance. This is fairly accurate to 100MHz or so. However, it does > not help us at all in figuring out where the plane resonances are and where > we should place caps to help with them. > > So, here is my wishlist. I don't require all to be addressed by same tool. > Depending on price - I'd be happy to get just some of the bullet points and > not all. > > - Figure out plane impedance curve > - Figure out plane resonance - where should we place caps > - Figure out resistive losses plus current distribution > - Be able to figure out tradeoffs between using higher capacitance > plane/ground structure vs using large number of caps vs using different > types of caps. > - Do pre and post layout simulation > - Have non-SI expert be able to run the tools > > So far Sigrity and HyperLynx PI (just announced) seem to do the job but at > quite substantial cost. I keep asking myself a question - what problem do > they solve vs cost (in license fees and training/simulation time) vs using > spreadsheet/simple simulation. So far I don't have a clear answer - thus I > am asking you for other ideas on approaching the power integrity problem. > > Thank you > Aleks > > > ------------------------------------------------------------------ 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 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 ------------------------------------------------------------------ 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 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