Subject: IBIS parameters....

From: Stephen Peters <[email-masked]>
Date: Fri, 08 Jul 1994 17:23:24 -0700

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.