DS250DF410: AC coupling caps

Hideki Hayashi1

Part Number: DS250DF410

HI experts,

Customer have question regarding 9.2.3.1 AC coupling capacitors in the range of 100 to 220nF are required for the RX inputs and TX outputs.

1. Please kindly let them know the most recommended caps? For example, smaller (100nF) is better or bigger (220nF) is better. Or recommended ESR...

2. Please kindly let them know the best layout recommendation? Recomended to be near the DS250DF410 pin or so on.

Best regards,

HIdeki

over 2 years ago

0 Rodrigo Natal over 2 years ago

TI__Mastermind 19135 points

100nF is ideal
You may reference the layout used on the TI DS250DF410 EVM board. You can obtain access to this layout file via TI.com product page request
- https://www.ti.com/licreg/docs/swlicexportcontrol.tsp?form_id=202045&prod_no=DS250DF410-DESIGN&ref_url=sva_sds

Thanks,

Rodrigo Natal

0 Hideki Hayashi1 over 2 years ago in reply to Rodrigo Natal

TI__Expert 6000 points

Hi Rodrigo,

I'm not sure but my altium can not open BRD file. Please let me know whether AC coupling capacitor is to be on near the pins or opposite?

Regards,

Hideki

+1 Rodrigo Natal over 2 years ago in reply to Hideki Hayashi1

TI__Mastermind 19135 points

Hi Hideki,

See link Altium instructional link below.

https://www.altium.com/documentation/altium-designer/allegro-import-ad

I've included below a picture of the DS250DF410EVM layout. In this case we placed the AC coupling capacitors opposite to the device BGA pads to minimize reflections near the retimer.

Thanks,

Rodrigo Natal

Interface

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DS250DF410: AC coupling caps