HD3SS3220: Questions about HD3SS3220 application issues

Jacky Wang(QD)

Part Number: HD3SS3220

Hi Team,

Customer is using HD3SS3220 in their design as DFP, but they found the the ID pin for HD3SS3220 can not work to low or high output when type-C U-disk inserted during test, can you help to check customer's schematic as below and see what's the problem in here?

Schematic:

PCB Layout:

Thanks a lot!

3 months ago

0 David (ASIC) Liu 3 months ago

TI__Guru*** 149885 points

Hi,

Since this is a DFP design, how are they controlling the VCC5V_USB3_A? You have to make sure the CC handshake is completed before enabling the VCC5V_USB3_A.

Thanks

David

0 Jacky Wang(QD) 3 months ago in reply to David (ASIC) Liu

TI__Genius 10320 points

Hi David,

Customer used ID pin to control load switch to make sure VCC5V_USB3_A enabling after CC handshake, please refer to below updated schematic. Please help to check if any issue for ID pin not working:

Thanks.

0 Shane Hauser 3 months ago in reply to Jacky Wang(QD)

TI__Genius 14545 points

Hi Jacky,

I have a couple comments on your schematic.

1. You need to have a pullup resistor on the ID pin or it will never go high. This is because ID is an open drain output. I recommend adding a 200K pullup on the ID pin.

2. You have both sides of the 3220 AC coupled on your TX lines. You should only AC couple one side of the MUX or your total capacitance will violate the 75nF minimum for the USB spec. I recommend removing C2124 and C2125

You can use the typical application schematic in the 3220 datasheet for a good reference on how to design this part in:

Let me know if you have any questions.

Best,

Shane

0 Jacky Wang(QD) 3 months ago in reply to Shane Hauser

TI__Genius 10320 points

Hi Shane, David,

Thanks for the support, customer's circuit works now, it is due to additional AC coupling capacitors. After removing them, it works now.

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HD3SS3220: Questions about HD3SS3220 application issues