TS3DV642-Q1: Design inquiry

Ailing Wang

Part Number: TS3DV642-Q1

Above is TS3DV642-Q1 demo design.For part A, why does HDMI and I2C connect to VCC with 0Ω resistor? Is it for sink termination ? and there is no mention the level of VCC .

Below is our use case, Whether partA is required or the value of resistor should be changed up to test result?

For part B, from my experience, it’s uncommon to add a coupling capacitor for HDMI bus ,and whether 0.22uF is accurate?

over 2 years ago

0 David (ASIC) Liu over 2 years ago

TI__Guru**** 178606 points

Hi,

Please see this e2e thread for my response, https://e2e.ti.com/support/interface-group/interface---internal/f/interface---internal-forum/1194833/ts3dv642-q1-evm-design-question.

Thanks

David

0 Ailing Wang over 2 years ago in reply to David (ASIC) Liu

Prodigy 140 points

Sorry, It shows that the page is not found

+1 David (ASIC) Liu over 2 years ago in reply to Ailing Wang

TI__Guru**** 178606 points

Hi,

1. TS3DV642-Q1 is a passive MUX that can support multiple interface standard such as HDMI, DP, MIPI, etc.

2. SCL, SDA, CEC, HPD have the same electrical characteristic as the data I/O, so they are all the same.

When I designed the TS3DV642-Q1 EVM, I was trying to make it as generic as possible. The 0ohm to VCC resistors are there if you have an interface that has the common mode voltage outside the TS3DV642-Q1 requirement. In this case, you want to AC couple both sides of TS3DV642-Q1 and then use the 0ohm resistor to VCC termination network to restore the TS3DV642-Q1 common mode voltage. The 0-ohm resistor is a placeholder and can be changed depending on the specific termination requirement.

HDMI 1.4/2.0 supports DC-coupling, so there is no need to have 0.22uF capacitors.

Thanks

David

0 Ailing Wang over 2 years ago in reply to David (ASIC) Liu

Prodigy 140 points

Hi ,

1,About 0ohm to VCC ，What's the value of VCC? Could it be same as the IC power 3V3?

2,Refer to the picture below, I2CB interface is not a common mode voltage,then it also pull to VCC， so I am still confused ,please clarify for me，

Thanks a lot！

0 David (ASIC) Liu over 2 years ago in reply to Ailing Wang

TI__Guru**** 178606 points

For this portion of the diagram, this is for implementing the external termination network if needed. VCC goes to the banana jack which allows you to supply a particular termination voltage including IC power 3.3V

SCL/SDA are just pin names, but they are the same as D0, D1, D2, and D3. But if you do use SCL and SDA in a HDMI application and connect them to the SCL and SDA pin of the HDMI receptacle, then SCL and SDA need to be pulled up to 5V through 2k resistors.

Thanks

David

0 Ailing Wang over 2 years ago in reply to David (ASIC) Liu

Prodigy 140 points

Hi David,

Sorry to bother you again !

About I2C voltage in the HDMI application,the I2CA and I2CB are from the HDMI input connector , and will be pulled up to 5V. I think that the DDC port connected with decoder should also be pulled up to 5V,but from the pin description it shows it's common port ,and the common port rated voltage should below 3.6V.

So can I pull DDC port up to 5V ?