HD3SS3220: HD3SS3220 design: invert TX/RX pin ?

Robert huynh

Part Number: HD3SS3220

Tool/software:

In the Document 'HD3SS DFP Dongle Evaluation Module ' The USB SS TX pins of the HD3SS3220 is connected to the RX pin of the Host and the Same for the USB-C connecteor at output .

This is not the case in the datasheet of the HD3SS3220 . What is the right connection ?

2 months ago

0 David (ASIC) Liu 2 months ago

TI__Guru*** 149885 points

Hi,

Both connections are correct, please see this e2e link for a detailed explanation, https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1304559/hd3ss3220-about-high-speed-signals-on-the-type-c-side.

Thanks

David

0 Robert huynh 2 months ago in reply to David (ASIC) Liu

Prodigy 10 points

Hi, Thank you david. Also the 0.47uF Caps are mandatory on TX pins(pin6 and 7) of HD3SS ?( They are not mentioned in the datasheet).

BR/robert

0 David (ASIC) Liu 2 months ago in reply to Robert huynh

TI__Guru*** 149885 points

Robert

USB3x spec requires TX must be AC coupled with AC coupling capacitor value between 75-265nF. Typical value is 100 or 220nF.

RX AC coupling capacitor is optional. If used, it needs to be 330nF.

So for pin 6 and 7 which are connected to SSRX, 0.47uF is optional and it should be 0.33uF if needed.

Thanks

David

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HD3SS3220: HD3SS3220 design: invert TX/RX pin ?