LM25149-Q1: How to disable the AEF?

Darius Babar

Part Number: LM25149-Q1

Tool/software:

Hi,

I want to disable the AEF, just to compare the EMI measurement results. I am trying to do it by connecting a jumper pin between CNFG and GND AFTER startup. But it does not seem to work. What am I missing?

EDIT: I have a 24.9k ohm resistor between CNFG and AGND.

2 months ago

0 Andrew Kutzler 2 months ago

TI__Genius 15310 points

Hi Darious,

Can you connect a Voltage source to CNFG that is below 0.8V?

Thanks,

Andrew

0 Darius Babar 1 month ago in reply to Andrew Kutzler

Prodigy 40 points

Hello,

I do not have a 0.8V source in my possession. My design is identical to LM25149-Q1EVM-2100, but with components for 440 kHz switching frequency.

The datasheet says tie CNFG to GND to disable AEF. But I am still getting the same EMI results.

0 Andrew Kutzler 29 days ago in reply to Darius Babar

TI__Genius 15310 points

Hi Darius,

It should only affect the conducted EMI. Can you try shorting out the the input pi EMI filter and try again? It might also be more noticeable if you try different frequencies or a lower quality inductor.

Thanks,

Andrew

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LM25149-Q1: How to disable the AEF?