LMR34215-Q1: CISPR25 class5

PAN-M

Part Number: LMR34215-Q1

Dear team,

Our customer is going to use this device by the 9V output.
Therefore, we choose a device of 400kHz.
As for the device of 400kHz, "Spread spectrum" is No, will you meet CISPR25 class 5 standard?

Best Regards,
PAN-M

over 4 years ago

0 Samuel Jaffe over 4 years ago

TI__Mastermind 25590 points

PAN-M,

Yes this device should be able to meet CISPR 25 class 5 at 400kHz with no spread spectrum. The 2.1MHz results are in the datasheet and show plenty of margin, but that's with spread spectrum. 400kHz will have >30MHz EMI about 15dBuV less and spread spectrum typically helps up to 10dBuV so you should have an extra 5dBuV on top of the results in the datasheet.

-Sam

0 PAN-M over 4 years ago in reply to Samuel Jaffe

Mastermind 8375 points

Thank you for answer.

Are four layers of boards necessary?

Regards,
PAN-M

0 Samuel Jaffe over 4 years ago in reply to PAN-M

TI__Mastermind 25590 points

PAN-M,

I have had success with a low-EMI 2-layer design. I do not expect 4-layers is required but please make sure to follow the layout guidelines in the datasheet.

-Sam

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LMR34215-Q1: CISPR25 class5