Scott-What leads to believe that the network has to stop at the Rx pad? If there are significant circuit elements between the Rx pad and the Rx termination, what leads you to believe that they would be excluded from the network analysis?
Please be aware that over a year ago, we proposed to IBIS ATM using on-die S parameters to solve a number of problems, including proper modeling of the on-die circuit elements. We've worked with several companies who use on-die S parameters because they feel it's a better way to model the analog behavior of the pin electronics. To date, such models must be considered to be proprietary and non-compliant with IBIS because there has been no action on the on-die S parameter proposal.
I also wonder what you mean by "large errors". What is your numerical estimate of the magnitude of such errors? How did you perform that estimate? What data did you base your estimate on?
Mike S. On 05/27/2010 05:31 PM, Scott McMorrow wrote:
Walter you would be incorrect. "Lumped approximations between TxTerm/TxPad and RxTerm/RxPad do not hold" A simulation based upon your assumption would have large errors. Scott On 5/27/2010 6:31 PM, Walter Katz wrote:Scot, I think a better picture is:TxTerm --- TxDie --- TxBump -- TxPkg -- channel -- RxPkg -- RxBump -- RxDie --- RxTerm| | | | TxPad RxPad Walter Walter Katz 303.449-2308 Mobile 720.333-1107 wkatz@xxxxxxxxxx www.sisoft.com -----Original Message----- *From:* Scott McMorrow [mailto:scott@xxxxxxxxxxxxx] *Sent:* Thursday, May 27, 2010 6:25 PM *To:* Walter Katz *Cc:* IBIS-ATM*Subject:* Re: [ibis-macro] another silly IBIS-AMI question about deriving the impulse response of a channelWalter,You are misinterpreting my picture. I was showing the network of just a Tx or Rx. When I say "network" I truly mean a circuit network. Let me create a better picture of the entire channel.TxTerm --- TxDie --- TxBump -- TxPkg -- channel -- RxPkg -- RxBump -- RxDie --- RxTerm| | | |TxPad RxPadFor a 50 ohm single-ended channel TxTerm = 50 ohm RxTerm = 50 ohm TxPad = some high impedance RxPad = some high impedance Lumped approximations between TxTerm/TxPad and RxTerm/RxPad do not hold What I was showing was just one part of the total channel. (50 ohm)RxBump --- Network --- RxTerm (50 ohm) | | RxPad (10k ohm)-- Scott McMorrow Teraspeed Consulting Group LLC 121 North River Drive Narragansett, RI 02882 (401) 284-1827 Business (401) 284-1840 Fax http://www.teraspeed.com Teraspeed® is the registered service mark of Teraspeed Consulting Group LLC