AnsweredAssumed Answered

(Video decoder)Full differential connect

Question asked by donadona999s on Apr 6, 2018
Latest reply on Apr 9, 2018 by donadona999s

Hi !


I want to confirm about Full-Differential connect.

At ADA4433x datasheet, this is written.

I think this is very usual use case.

Everything is connecting with 75Ohm so nothing will be problem.


But at this thread ADI's comment was "Using 150Ohm is correct".

(ADV7281A)Reference circuit. 

But if we use 150Ohm at CVBS-DIFF Rx, I think Impedance matching can not be secured.



At ADI recommends, it says 150 ohm should be used when we use Differential input.

But as I wrote, I think Impedance matching can not be secured because other impedance are 75Ohm.

What kind of value for cable impedance and which impedance value for output of CVBS - RX are do ADI assume?



Should our customer select 75Ohm for R1 when the output impedance is 75Ohm and cable impedance is 75Ohm?



If 150Ohm is correct, please explain why 150Ohm is correct.


Best regards