IBIS parameters....

Hello Syed: My answers are below, prefixed with a >>....

Hi,
        Some questions about the IBIS parameters:

        When we specify R_pkg, Do we really mean the Resistance of the pin or
        the Impedence of the pin. This makes a lot of difference
        in calculation of R_pkg. Impedence is an easy calculation(based on L & C)
        but something like Resistance needs Bond wire length, Area of wire,
        resistivity of the wire etc to get R_pkg.

>> I have always taken R_pkg as the DC resistance of either the
>> bond wire/pin or the trace resistance of a trace in a PGA package.

        Any idea how someone gets these R_pkg numbers. Don't say from the
        packaging group !!

>> OK, I won't say it :-). If you have a mechanical sample perhaps
>> you could use a low ohm meter and make a direct measurment.

        Also, the C_comp. How does one measure this ? I know of measuring this
        using TDR method and comparing with known capacitance curves but that
        is not too straight forward. Any ideas !!

>> If you have a tristateable device you can hook the output thru a
>> resistor to a very fast (pS) rise time pulse generator. Send a
>> pulse thru the resistor and into the output then measure the RC
>> time constant. (This is what I do in a simulation environment.)

>> I hope these sugestions help.

                Best Regards,
                Stephen Peters
                Intel Corp.

Regards,
Syed Huq
National Semiconductor Corp.
Received on Fri Jul 8 17:26:48 1994