DS90UB921-Q1: DS90UB921-Q1 Layout Issue

Steven Liu1

Part Number: DS90UB921-Q1

Hi Team,

My customer is using the DS90UB921-Q1 from RGB to COAX.

One question related to the capacitor and resistor layout goes that:

where is the best position to put the C1, C2 and R7? is it better to put it closer to the silicon or the FAKRA connector?

Any impedance control requirement?

over 6 years ago

0 Michael.Walker over 6 years ago

TI__Mastermind 19720 points

Hello Steven,

The AC caps should be as close to the 921 as possible. For the resistor most of our customers put the resistor close to the 921 due to space constraints, but if the resistor is placed near the connector it helps reduce any noise that could be coupled on the DOUT+ line.

Regards,
Michael W.

0 Steven Liu1 over 6 years ago in reply to Michael.Walker

TI__Expert 4455 points

Thanks Walker!
Your reply answered my question. Thanks a lot!
One additional questions is that do we need any resistor, such as 49.9ohm, on the DOUT- line?

0 Michael.Walker over 6 years ago in reply to Steven Liu1

TI__Mastermind 19720 points

Hello Steven,

Yes, you do need a ~50 ohm resistor on the DOUT- line.

Regards,
Michael W.

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DS90UB921-Q1: DS90UB921-Q1 Layout Issue