SN74AUP1T34: IBIS Model shows too fast rise / fall times for AUP logic and low output impedance

Ulrich Schratter

Part Number: SN74AUP1T34

We commonly use AUP logic for slowing down rise and fall times. In a new design we use the part SN74AUP1T34 but we see very fast rise and fall times (350ps) in ibis simulation (aup1t34a0.ibs). Also ouput impedance in simulation is much lower than typical for AUP devices (23 Ohm).

Can I trust this simulation model?

Kind Regards

Ulrich Schratter

over 8 years ago

0 Michael J Schultis over 8 years ago

TI__Mastermind 24975 points

Hello Ulrich,

While the simulation models can be a good guide in many cases to help understand the device behavior, they dont always perfectly simulate the actual device characteristics. These models are behavioral models to help guide understanding, but aren't a perfect replacement for bench testing and characterization.

Is it common that you use the AUP parts to slow down rising and falling edges? Is this to help reduce ringing?

Best,
Michael

0 Ulrich Schratter over 8 years ago in reply to Michael J Schultis

Prodigy 20 points

Hello Michael,
thank you for your quick reply.
Yes, we try to use logic families with slowest possible raise/fall times for SI and EMC issues. We have good experience with using AUP logic. Furthermore series termination can be omitted with this type.
Kind Regards,
Ulrich

0 Michael J Schultis over 8 years ago in reply to Ulrich Schratter

TI__Mastermind 24975 points

Ulrich,

Very happy to help!
Our product experts are constantly monitoring these forums in order to respond in a timely manner, so I would encourage you to continue using this as a resource to help aid in your designs, and we are happy to help.
Good luck in your design.

Best,
Michael

Logic

Logic forum

SN74AUP1T34: IBIS Model shows too fast rise / fall times for AUP logic and low output impedance