EMI noise with LNK306

Posted by: kienhoefer on 04/06/2014

We are using the LNK306 to power a touch field sensor AT42QT1011 for example. This device generates a electric field around an electrode. We have problems that the switching supply generates so much EMI noise that the touch sensor gets errors recognizing touches.

What is the best practice to reduce the noise? Coil shielding?

Thanks for your help

Jueren

Comments

Are you following the recomendations for PCB layout?

I am not sure if you have buck converter , if you d, are you using the inductor recomended in the application notes?

Hi PI-worf,

I have the same problem with Jueren. I used LNK306 power supply for Touch board, but the touch IC sometine can not recognizing touches.

Because of the PCB space limit, I can not have the same layout with the datasheet guide. The inductor we used is a copper wire around a ferrit coil, the inductor is about 1 mH.

I tested with another load, LNK306 was good, no sound, maximum current output was about 12V-300 mA. But when I supply for my touch board, it was not worked. When I change the power supply adapter, the touch board was worked well.

Please suggest me some solutions for this problem.

Thanks,
Dat

Hi,
Thanks for contacting PI.
For a A B comparison, what is the topology of the power supply adapter? Is it isolated power supply like flyback, or it is the same buck converter?
Thanks