Electromagnetic interference issues of PCB

Thread Starter


Joined Mar 13, 2023
Hey,guys!Today I find an annoying phenomenent of my PCB borad.
A Chip,LT8316, and some components on the front of the PCB borad.A LED on the back.And chip controls the On-off of a NMOS to control the power supplied to LED.When I tested the borad alone,the LED almost brighted perfectly.But when I let a metal plate get close to the area around the LT8316 whether from the front or the back,the LED turnt into dark no more than a second.And I found if there was something electrically conductive get close to the LT8316,the LED shut down,too.
I have already tried to put two piece of fomex(a kind of insulating material) on the chip,but it can't prevent this phenomenent from happenning.And I need to let the led sticked to a metal wall in my real usage scenarios and there is no space for the third piece.I want to ask you guys,do you have any strong and space-saving method can solve this problem?Or do I need to modify my PCB design?And how should I change it?
Fllows are my design documents of my PCB borad.