TIDA-00891: hd3ss3220

Doron Darmoni

Part Number: TIDA-00891
Other Parts Discussed in Thread: HD3SS3220

Hi,

i try to open the schematics reference design in the tidrk94.zip but the tida-00891 sch.opj is empty when open it in orcad

the tida-00891 sch.dsn is missing

thank you

Doron

over 5 years ago

0 Malik Barton57 over 5 years ago

TI__Guru 64326 points

Doron,

We are aware of this. Unfortunately we only have the .pdf of the schematic at this time for TIDA-00891.

0 Doron Darmoni over 5 years ago in reply to Malik Barton57

Prodigy 125 points

do you have other schematics of the hd3ss3220 in orcad capture format?

0 Malik Barton57 over 5 years ago in reply to Doron Darmoni

TI__Guru 64326 points

Doron,

I can send you the design files for the HD3SS3220 EVM. Please accept my request and post once you have done so.

0 Doron Darmoni over 5 years ago in reply to Malik Barton57

Prodigy 125 points

Hello,
i did it thank you
Doron

0 Malik Barton57 over 5 years ago in reply to Doron Darmoni

TI__Guru 64326 points

File have been sent.

0 Doron Darmoni over 5 years ago in reply to Malik Barton57

Prodigy 125 points

Thank you
what is the reason for the Pull Down resistors on the Host/Device USB SuperSpeed differential Signals (pins 6-7, 9-10)?

thank you,

Doron

0 Malik Barton57 over 5 years ago in reply to Doron Darmoni

TI__Guru 64326 points

Doron,

These pull down resistors are there due to some issues seen with early Type C devices. When connected to the EVM there would be a common mode voltage difference between SSTX on the EVM and SSRX on device. In order to combat this we added AC coupling caps and pull down resistor in order to bring the common mode on the EVM low. The resistor however are optional but we recommend AC coupling caps on SSTX (0.1 uF) and SSRX (330 nF) when routing to a connector.

0 Doron Darmoni over 5 years ago in reply to Malik Barton57

Prodigy 125 points

Hi Malik,
if i connect the hd3ss3220 SSTX /SSRX to a USB3 controller (NXP LS1020A) are the PD resistors required ?
the AC couple is on one side only ? the other suppose to be on the USB device? doesn't matter the USB mode (UFP/DFP/DRP)?
thank you
Doron

0 Malik Barton57 over 5 years ago in reply to Doron Darmoni

TI__Guru 64326 points

Doron,

if i connect the hd3ss3220 SSTX /SSRX to a USB3 controller (NXP LS1020A) are the PD resistors required ?

The PD resistor are only used for the connector side of HD3SS3220 not the host controller side.

the AC couple is on one side only ? the other suppose to be on the USB device?

Normally yes, HD3SS3220 needs to have some common mode bias with AC caps on one side. However if AC caps are needed on both sides due to common mode conflict then biasing between HD3SS3220 and AC cap is needed.

doesn't matter the USB mode (UFP/DFP/DRP)?

HD3SS3220 can handle all of these port configurations.

0 Doron Darmoni over 5 years ago in reply to Malik Barton57

Prodigy 125 points

Hi Malik,

The PD resistor are only used for the connector side of HD3SS3220 not the host controller side.-

On the reference design (TIDA-00891), the HD3SS3220 is between 2 connectors . there is no controller. I see PD on the Type A connector side.

also, I see the AC caps on the Rx on one side and on Tx1/2 on the other side.
assuming that there are AC caps on the Tx on one side and on the Rx1/2 the other side?

Thank you,

Doron

0 Malik Barton57 over 5 years ago in reply to Doron Darmoni

TI__Guru 64326 points

Doron,

Could you please rephrase your question? I do not think I understand what you are asking. Are you asking where AC caps are necessary?

0 Doron Darmoni over 5 years ago in reply to Malik Barton57

Prodigy 125 points

Hello Malik,

I will rephrase my question-

I connect the hd3ss3220 Tx/Rx side to USB controller- LS102xA . and the TX1/Rx1 & TX2/Rx2 side to the USB3 type-c connector.

Where the ac couple caps required?

On both sides?

On each side both Tx & Rx or only one of them?

On the LS102xA reference design used the USB5534B hub and placed ac caps on the connector side on both the SSTX & SSRX while on the controller side only on the controller SSTX

Thank you,

Doron

0 Malik Barton57 over 5 years ago in reply to Doron Darmoni

TI__Guru 64326 points

Doron,

Where the ac couple caps required?
- The AC caps for this application are required on the connector side.
On both sides?
- The AC caps are not required on the host side but can be placed if necessary. If AC caps are place on both sides then biasing will be need for the switch. I do not recommend placing AC caps on the host side
On each side both Tx & Rx or only one of them?
- AC caps on TX (connector side) are required, use 220nF . AC caps on RX (connector side) are optional, use 330 nF.

0 Doron Darmoni over 5 years ago in reply to Malik Barton57

Prodigy 125 points

Hello Malik,

[thank you for the detailed answer.

what do you mean by biasing if AC coupled used? should i add a 0-2V voltage between the caps and the hd3ss3220?

on the reference design , i see AC caps on the RXp/n (C18/C20) and no biasing (only 100K PDs).

also, the suggested below 220nF/330nF are not out of spec? 75-200nF?

thank you,

Doron

0 Malik Barton57 over 5 years ago in reply to Doron Darmoni

TI__Guru 64326 points

Doron,

HD3SS3220 needs to have a DC bias, if AC caps are place on both sides then external biasing is needed. The 100K PDs are apart of this biasing. Due tot he nature of the EVM, with connectors on both sides it is best to have AC Caps on RX and TX for both sides of the device.

The USB 3.2 AC coupling caps spec for transmitters and receivers are below. Recommendations are within these specs.

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TIDA-00891: hd3ss3220