TPS51116: TPS51116 Failure in EMC Test

Steven Liu1

Part Number: TPS51116

Hi Team,

My customer is using TPS51116RGE as the DDR3 powering device. Recently they're doing the EMC test. The 4kV lighting surge test was implemented to their board and it would lead to the failure of the TPS51116's 1.5V output, it dropped to 0V.

After multiple tests, a relay coil, which located very near the TPS51116 is very suspicious to be the root cause that leads to the failure.

See below picture for details: the distance between the TPS51116 device and Relay Coil is about 10 mm.

If a shield is applied to the top of the TPS51116, it would help to benefit the result.

So the question would be why the lighting surge test affect the TPS51116 by the relay coil?

Is there any other risk you could see with this design?

Thank you!

over 4 years ago

0 Qian Chen over 4 years ago

TI__Mastermind 24075 points

Hi Steven,

It looks the radiate noise from relay coil is coupled to TPS51116 pins and damage the part.

Can you compare the pin impedance (with respect to ground) of damaged part and good part, so we can get an idea which pin is damaged?

Thanks

Qian

0 Steven Liu1 over 4 years ago in reply to Qian Chen

TI__Expert 4380 points

Hi Qian,

Thanks for your quick reply!

Actually, the part is not damaged. If power down and up, TPS51116 would give the correct 1.5V output.

Additionally, if adding a shield case on top of the TPS511116, the failure would not happen again with the EMC test.

So the question is: How the lighting surge test could cause the TPS51116 failure temporarily?

Any idea about optimizing the test if not adding a shield case on top of the device?

0 Qian Chen over 4 years ago in reply to Steven Liu1

TI__Mastermind 24075 points

Hi Steven

Can you send the schematic to my email box?

Just want to check if we can do anything to make the circuit less sensitive to noise.

Thanks

Qian

0 Qian Chen over 4 years ago in reply to Qian Chen

TI__Mastermind 24075 points

This issue is supported offline.

I will close this post.

Thanks

Qian

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TPS51116: TPS51116 Failure in EMC Test