LM5009A: The re-circulating diode have failed for a period of time.

Leo Liu

Prodigy 10 points

Part Number: LM5009A

Tool/software:

We have designed the LM5009A in our power system.

Recently, we found there are failures occurring on the LM5009A related power rail.

After our investigation, we found that the re-circulating diode was damaged.

The whole system appears to function normally except for this issue.

Do you have any recommendations for this situation?

(The Schottky diode used is SS110, 100V/1A.)

1 month ago

0 Niranjan Nair 1 month ago

TI__Genius 11130 points

Hi,

What is the input voltage and load current of the LM5009A?

Regards,

Niranjan

0 Leo Liu 1 month ago in reply to Niranjan Nair

Prodigy 10 points

Hi Niranjan,

The input voltage is 54V, and the output voltage is 3.3V. The load current is approximately 0.3A.

Regards,

Leo Liu

0 Niranjan Nair 1 month ago in reply to Leo Liu

TI__Genius 11130 points

Hi Leo,

The LM5009A is a 0.15A device, it should not be used at 0.3A load current. The device will always be in current limit in that case and regulation might not be proper. I am not sure if this is related to the diode damage but it should be changed anyways.

Can you also probe the SW node waveform and send?

Regards,

Niranjan

0 Leo Liu 1 month ago in reply to Niranjan Nair

Prodigy 10 points

Hi Niranjan,

Thank you for your reply. I reconfirmed that the load current should be 0.1A instead of 0.3A. Sorry for that.

Regarding the SW node waveform, I’ll probe it and provide the waveform for check.

Regards,

Leo Liu

0 Niranjan Nair 1 month ago in reply to Leo Liu

TI__Genius 11130 points

Hi Leo,

Sure, I will wait for that

Regards,

Niranjan

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LM5009A: The re-circulating diode have failed for a period of time.