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INN3268C-H202-TL EMI problems

Posted by: Ensider on 11/11/2021

Good day! We use your INN3268C-H202-TL microcircuit in the power supplies. The problem today is that when a 4kV EMI is supplied with a frequency of 5kHz and 100kHz with different grounding polarities, a short-term decrease in the set value of the output voltage occurs, first to 14V, then to 0V. After removing the interference, the set value of the output voltage is not restored and remains equal to 14V. I attach the oscillogram and the circuit in the attachment. The block parameters are output 24V and 2A. It is worth clarifying that the experiment was carried out at maximum load; at minimum load at the output, this behavior of the block did not manifest itself. EMI tests for 1kV and 2kV units were successful. Thanks.


Attachment Size
VOUT 51.15 KB
Shematic 206.08 KB
SR FET 41.84 KB


Submitted by PI-Chloe on 11/16/2021

Hi Ensider,

Good day! 

I would like to know the specific EMI test that your doing. 





Submitted by Ensider on 11/17/2021

Hi PI-Chloe!

I do an EMI test for electrical fast transient (EFT)/burst transients.


Attachment Size
Снимок_5.PNG 9.36 KB
Submitted by PI-Chloe on 11/24/2021

Hi Ensider 

Good Day! 

Asked if there are reported for this kind of concern. We did not receive this king of concern or experience any when designing INNO3. 

I think there is a layout concern that makes the EFT enters the power supply.

The MOV, Xcap, bulk cap should help to prevent the EFT from entering the circuit.

I also observed that there is a lot of Ycap, I'm thinking that it can be a possible path of the EFT depending on the PCB layout.