AM6548: SerDes AC capacitor placement

Sushruta Shetty

Part Number: AM6548

Hi Team,

We are designing a SoM with AM654 SoC.

We are planning to use SERDES Interface in the design. Could you please let us know the recommendations for the ac coupling capacitor placement.

As per the TRM section "12.2.4.4.4 Terminations", capacitor is recommended to be placed near the receiver pin of the BGA, unless PCIe interface is used. Does this hold good even for Superspeed USB lines?

What shall be the effect if placed near the transmitter pin.

Kindly advice.

Regards,

Sushruta

over 6 years ago

0 -DK- over 6 years ago

TI__Mastermind 27890 points

Hi Sushruta,

Not to ignore your question, but I'm not clear on the published requirements for cap placement being different for SS USB and PCIe. I know of no reason why that would be the case. Let me do some work on digging up that answer and perhaps it will also answer yours in the process.

I'll update this thread when I have the info, or Friday 6/28 with status.

0 -DK- over 6 years ago in reply to -DK-

TI__Mastermind 27890 points

Hi,

I'm still waiting for feedback from a coworker who is out until Monday. I'll provide a further update then.

0 -DK- over 6 years ago in reply to -DK-

TI__Mastermind 27890 points

Hi,

I've forwarded this to the IP designer for an answer. Hopefully not too much longer...

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AM6548: SerDes AC capacitor placement