SN74CB3Q3257: IBIS model issue

Hailiang Zhang

Tool/software:

Hi Team，

SN74CB3Q3257PWR Pin 4/7/13/14 set output in our design, but only "IN" Pin type in this ibis model, would you pls help to check it?

Besides，Is there a replaceable model that includes output pins, how about SN74HC744?

Regards，
Hailiang

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 321020 points

In the IBIS model, the I/O pins are neither inputs nor outputs, they are modelled as series switches. If they are shown as "IN" type, then your software is wrong.

0 Alex Vish over 1 year ago

TI__Genius 10552 points

Hi Hailiang,

This is a common question we get. The IBIS model does not define I/O pins as inputs nor outputs since it's just a passive switch. They're modeled as a series switch as Clemens described. The model itself has no issues.

If there's a chance they're using hyperlynx, we had a similar post in the past on how to resolve this.

Regards,

Alex

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SN74CB3Q3257: IBIS model issue