SN65LVDS180: SN65LVDS180 Signal Integrity (on "R" pin)

Matthew Huff

Part Number: SN65LVDS180

I'm having some difficult understanding some results I'm seeing with a Hyperlynx simulation using the IBIS model for SN65LVDS180.

On a rising edge I"m seeing a pull-down to -0.5 V before rising up. This is causing some pretty nasty reflections in the signal.

I've noticed that the SN64LVDS32 does NOT do this. This is what I was expecting to see...

My question is...

Is the IBIS model for the SN65LVDS180 part correct? Does it really pull down low before rising to a "high" level?

over 2 years ago

0 Joshua Salinas over 2 years ago

TI__Mastermind 22400 points

Hello Matthew,

Can you provide us with your simulation setup?

Regards,

Josh

0 Matthew Huff over 2 years ago

Prodigy 10 points

Unfortunately that I can't do. I can tell you all I did was set up a standard (ideal) transmission line (50 Ohm) with this IBIS model and a generic receiver. The transmission line was about 8 inches with no vias. I used a variety of source series termination values, but all of them showed this behavior for the LVDS180. If I changed the IBIS model to the SN64LVDS32 chip, the issue went away.

0 Joshua Salinas over 2 years ago in reply to Matthew Huff

TI__Mastermind 22400 points

Matthew,

Thanks for the information. Please give us time to see if there are any issues with this IBIS model. Thank you.

Regards,

Josh

0 Joshua Salinas over 2 years ago in reply to Matthew Huff

TI__Mastermind 22400 points

Hello Matthew,

Thank you for you patience and I apologize for the delay. It seems there are a some inaccurate data points with the SN65LVDS180 IBIS model. Due to upcoming IBIS model for our newer devices, unfortunately I cannot give a timeline when our design team can start on a remodel for this part.

Regards,

Josh

0 Matthew Huff over 2 years ago

Prodigy 10 points

Joshua, Thank you for the information. I'll await an updated model.

0 Joshua Salinas over 2 years ago in reply to Matthew Huff

TI__Mastermind 22400 points

Matthew,

I will let you know when an update for this IBIS model is released. Thanks.

Regards,

Josh

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SN65LVDS180: SN65LVDS180 Signal Integrity (on "R" pin)