TDP158: TDP158 Strap pin adjust the output signal common mode voltage

Vincent Li00

Intellectual 2035 points

Part Number: TDP158

Hi Guys

Our customers are using our TDP158 as a re-driver for HDMI. Application is Scope.

when we test the Eye Diagram. Input signal is differential signal and the common mode voltage is equal to 0. however We didn't find the output of TDP158 reach the Standard Voltage of HDMI. You can see the out put of TDP158 below. The signal VL is 2.01V and Eye height is 520mV. But we have to make the VL between 2.7V and 2.9V. Right? how to adjust the Eye height by using strap pin or any other solution to adjust it? We don't want to use the I2C to adjust it because of to much software work. The schematic is below. Please check it.

The out put of TDP158:

Schematic:

Any feedback are appreciated. Very urgent issue.

Thanks

over 5 years ago

0 Malik Barton57 over 5 years ago

TI__Guru 64326 points

Vincent,

TDP158 common mode voltage seems to be off on the output. Are there AC coupling capacitors on the input? Could not see via your schematic. Also VL should between 2.7 and 2.9 V.

0 Vincent Li00 over 5 years ago in reply to Malik Barton57

TI__Intellectual 2035 points

the input signal is for Clock signal. and the input signal is AC signal please see below:

0 Vincent Li00 over 5 years ago in reply to Malik Barton57

TI__Intellectual 2035 points

Hi Malik
We have told customer to remove the ESD and load switch part on the schematic and add a remote terminate pull up resistance to 3.3V. By using the high impedance probe to test the signal again.
More info will go next.
Thank you

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TDP158: TDP158 Strap pin adjust the output signal common mode voltage