AnsweredAssumed Answered

(ADV7181D)What will happen if some kind of noise inputs to unused pin.

Question asked by donadona999s on Aug 23, 2017
Latest reply on Sep 14, 2017 by JeyasudhaMuthuPerumal



First I have to explain the back ground.


(Back ground)


Our customer have a problem at their system.

They are using ADV7181D AIN 3 ports for CVBS.

So other ports are connected to GND directly.

ADV7181D input signal pin 

The circuit is this.

At their system ,the SoC will read back ADV7181D's IN_LOCK bit and if system detect ADV7181D unlock CVBS SoC will quit output the image.

And at they said they detect IN_LOCK some time even when they input CVBS correctly and the system quit outputting image.

The CVBS source is rear view camera so this problem is very critical issue for them and we want to solve this problem.

I'm asking them to do this,

1) Check I2C waveform.

2) Check Analog input waveform.

3) They are using ADV7181D at past MP model so do the cross check.

     (connect same image source to past model and check)

4) I'm asking to change software not to read back IN_LOCK and check that is it ADV7181D problem or SoC problem/

5) Also I'm trying to detect CVBS unlock at my lab with the EVAL board to find more easier way to debug

    but it is not working.  => (ADV7181D)To detect unlock analog input. 




So my question are these.

(My question)



Do you have same kind of experience?

If you have , can you share the information?



When they input CVBS at one port (Ex,AIN4) , there are not input to other port(Ex, AIN1 & 3).

AIN1 & AIN3 is connected to GND with 75Ohms.

AIN2 & AIN5~10 are connected to GND directly.

And off course they are selecting AIN4 at their software.

At this case , if some kind of noise goes into AIN1 or AIN3 , would ADV7181D unlock AIN4 CVBS lock?



If you can help about this quickly it will be help for us and also our customer and OEM.

We can give you the full circuit with e-mail if you want.


Best regards