HD3SS3212: AC capacitor placement questions

John Liu59

Part Number: HD3SS3212

Dear,

For HD3SS3212, in datasheet, AC capacitor of the TX can be put close to the host controller or close to the connector, in the real application, is there any difference between the two placement? what should be considered for the two placement?

Thanks.

over 6 years ago

0 Malik Barton57 over 6 years ago

TI__Guru 64326 points

Hi,

The AC coupling ideally would be in between the connector and HD3SS3212 as you want to black the "unknown" VCM from devices connected to the port. Please ensure that VCM o host is compatible with HD3SS3212.

0 John Liu59 over 6 years ago in reply to Malik Barton57

TI__Intellectual 2735 points

Hi Malik

If connect the AC coupling cap between HD3SS3212 and connector, and B0p,B0n, C0p,C0n is TX+, TX- signal, then there should be 0.1uF cap connect to theB0p,B0n,C0p,C0n, and for RX+,RX-(B1p,B1n,C1p,C1n), no cap is required.

Also for A0p,A0n,A1p,A1n which connect to the host side, no cap is required, am I right?

Thanks.

0 Malik Barton57 over 6 years ago in reply to John Liu59

TI__Guru 64326 points

Hi,

We recommend using 220 nF on TX and 330 nF on RX paths. That is correct A0 and A1 pins do not need AC coupling caps if placed on Bxy and Cxy pins.

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HD3SS3212: AC capacitor placement questions