TUSB9261: AC coupling capacitor at host or device side

Shifali N

Expert 2145 points

Part Number: TUSB9261
Other Parts Discussed in Thread: TUSB1002A

Hi,

I am using tusb9261 host in my design. I would like to understand the coupling capacitor connector.

1. Should the capacitor be present in both TX and RX lines of Host and Device side

2. Should the capacitor be present only in both TX and RX lines of Host side or Device side

Also the recommended value for SATA as per spec is 0.01uF. Why is 0.1uF considered. Any specific reason.

over 4 years ago

0 Malik Barton57 over 4 years ago

TI__Guru 64326 points

Hi,

Per USB spec, SSTX should be AC coupled with 100nF and SSRX can be optionally AC coupled with 330 nF. This is used when AC coupling to a external USB connector. For a embedded connection, no external USB connector, both SSTX and SSRX can be AC coupled with 100 nF.

Per SATA spec, both TX and RX should be AC coupled. 0.01uF should be used on the SATA side only.

0 Shifali N over 4 years ago in reply to Malik Barton57

Expert 2145 points

Hi Malik,

Thankyou for your response.

I would like to know for SATA specification, can the coupling capacitors be placed in both TX and RX lines of Host and Device Side.

0 Malik Barton57 over 4 years ago in reply to Shifali N

TI__Guru 64326 points

Hi,

Yes AC coupling is used on both sides, Host and Device when using a external connector. See example image below from the TUSB1002A datasheet.

Interface

Interface forum

TUSB9261: AC coupling capacitor at host or device side