LMR16006: To much EMC noise

Michael Larsen59

Part Number: LMR16006

Hi Texas!

I have used LMR16006Y to supply 15V ~0.2A, with 36V input voltage, but it seams to emits more noise than accepted by EN55011.
First I though that the noise was due to my "bad layout", so I changed my layout according to App notes,
but it still emits to much noise.
I have tested TI's evaluation board with 18V input battery and 5V output, and 50R load.

The EMC noise from the Evaluation board is about 20dB too high!

What can I do? can anyone give me an alternative to LMR16006, the input voltage is 36V but must tolerate 50V

over 8 years ago

0 Arief Hernadi over 8 years ago

TI__Mastermind 23845 points

Will this help?
www.ti.com/.../PMP15013

You can try to use LMR16006X which has a lower frequency (700kHz).

Thanks
-Arief

0 YangZhang over 8 years ago in reply to Arief Hernadi

TI__Genius 11085 points

You can add an input filter to before the LMR device. The input filter can reduce both conducted and radiated EMC.

Please refer to this app note for more details:
training.ti.com/.../snva755.pdf

0 Michael Larsen59 over 8 years ago in reply to YangZhang

Prodigy 40 points

Hi Yang and Arief!

Thank you for your prompt reply!

To Arief: You are right, when I use a LMR6006X the EMI is reduced, but not enough, and the phase margin is getting too narrow, but thanks for the input, it would have been a been a smart fix!

To Yang: The app note is very usable, and it might solve the problem, but I think that I have to find a solution I know will pass the EMI:

Our customer is not impressed by us, this would be the third redesign and the third extern EMC Test, and I want it to pass; so I think we will try to find the space on the PCB and use a linear solution! burning off around 2W !!

It is not nice, but I am over the EMI problem.

Thank you for your support

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LMR16006: To much EMC noise