SN65DP141: Trace impedance of SN65DP141...

Peter Tseng

Part Number: SN65DP141

Dear Sirs,

I have a question about the suggested impedance of DP141.

In the datasheet page24, the application schematics suggest the impedance is 90ohm.

And in the layout guide section mentioned, the diff. pairs impedance is 100ohm.

In the customer side, the chipset vendor suggests using 85ohm.

The customer gets confused about which one they should follow.

Please help to verify!

Thanks.

0 David (ASIC) Liu over 4 years ago

Hi,

Between the source and the DP141, I will follow the chipset vendor recommendation of differential 85ohm.

Between the DP141 and the DP connector, I will follow the DP spec recommendation of differential 100ohm.

Thanks

David

0 Peter Tseng over 4 years ago in reply to David (ASIC) Liu

Dear Sir,

Thanks for reply!

But how to explain the 90ohm suggestion in page24 if DP spec. is 100ohm.

0 David (ASIC) Liu over 4 years ago in reply to Peter Tseng

Hi,

I am not sure why the schematic says 90ohms,. From the DP specification, it requires the differential impedance to be 100ohms +-10%.

Thanks

David

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