EDN Article and IBIS

          Howdy,
          
          I don't know how clear it was at the meeting, but I wanted to
          again point out the article in EDN which I believe is
          pertinent to IBIS. Please reference "Treat pc-board traces as
          transmission lines to specify drive buffers", EDN Sept. 2 1993
          page 129.
          
          The article shows that the best way to design/qualify a buffer
          for proper AC operation is by referencing its V/I curve (and
          not its DC sink current). Furthermore, it's the best way to
          achieve similar drive capabilities across various vendors and
          processes (a concept I've been able to convince Intel of as we
          create "compatible" chipsets and processors). For the first
          time (that I'm aware of) it's quite clear what's meant by a
          "PCI driver."
          
          All of us probably would have seen a lot less manufacturing
          problems if "LS" or "F" parts were equated through their V/I
          curves rather than "24mA", "64mA", or some such nonsense,
          across vendors.
          
          And yes, I'm aware that this doesn't work with certain types
          of buffers (which we feel are handled by T/V/I). But I think
          it's a good start if people begin looking at where dynamic
          performance really comes from. And for IBIS, the data and
          methods are akin to the underlying structure.
          
          Comments?
          Don Telian
Received on Thu Sep 16 09:43:36 1993