Re: Use of [Ramp] keyword

>>>>> "FITZPATRICK" == FITZPATRICK John <uunet!ln.cit.alcatel.fr!John.Fitzpatrick> writes:

    FITZPATRICK> Hello all, A short question regarding interpretation
    FITZPATRICK> of a model:

    FITZPATRICK> In the IBIS 2.1 spec, the ramp rate is defined as

    FITZPATRICK> dV 20% to 80% voltage swing -- =
    FITZPATRICK> -------------------------------------- dt Time to
    FITZPATRICK> take to swing the above voltage

 
    FITZPATRICK> When I scan through a random set of IBIS models, I
    FITZPATRICK> see the following entries after the [Ramp] keyword of
    FITZPATRICK> the following types:

    FITZPATRICK> a) dV/dt_r 1.84/0.65n 1.77/0.65n 1.87/0.53n

    FITZPATRICK> b) dV/dt_r 4.1/1n 1.6/1n 8.2/1n

>> From my point of view, a) is correct, but b) is not good.

    FITZPATRICK> I would like to be able to extract dV and dt
    FITZPATRICK> individually. As [Ramp] is an obligatory keyword, I
    FITZPATRICK> hoped it would be safe to do so .... until I saw b).

    FITZPATRICK> Thanks for your help, John

You are right, b is probably meaningless (unless the risetime happens to
be 1ns. What model was this in?

Jon
Received on Wed May 15 08:43:42 1996