LM5013: Part burns always at the same spot

Isaac Atia-Abugbilla

Part Number: LM5013

Tool/software:

I made a pcb with where I am taking about 52v as input and outputting 12v using LM5013 step-down converter. I have attached a picture of my schematic below. Soldering was also done very well and I double checked all parts to make sure they were current. However anytime I pass the input voltage, the converter catches fire and burns always at the same spot [ the EN pin]. From the datasheet this converter should be able to handle up to a 100 volts so I think 52v should not be a problem. I have already burnt about 4 of those chips always at the same spot. What could be the issue

9 months ago

0 ARPITA NATH 9 months ago

TI__Expert 6392 points

Hi Isaac,

Please fill in the LM5013 Quick-Start calculator and share with us.

Have you captured any waveforms during the start-up? Please provide waveforms (if captured any) and PCB layout for further investigation.

regards,

Arpita

0 ARPITA NATH 9 months ago in reply to ARPITA NATH

TI__Expert 6392 points

Hi Isaac,

Try placing may be 22uF electrolytic capacitor at the input side in parallel with input capacitors and check is the issue is resolved.

It is recommended to use the electrolytic capacitor at the input parallel to the input pin and GND. When the input DC source is hot plugged to the device with long cables, due to long cable inductance / PCB trace inductance and ceramic capacitor the LC oscillation will happen, and which causes the voltage to cross abs.

Regards

Arpita

0 Isaac Atia-Abugbilla 9 months ago in reply to ARPITA NATH

Prodigy 30 points

Unfortunately the device does not stay on long enough for me to capture a waveform on an oscilloscope before it fries. I have however provided the pcb layout.

0 Isaac Atia-Abugbilla 9 months ago in reply to ARPITA NATH

Prodigy 30 points

This is the updated quick-start calculator filled for your reference

5468.LM5013 Design Calculator revB.xlsm

0 ARPITA NATH 9 months ago in reply to Isaac Atia-Abugbilla

TI__Expert 6392 points

Hi Isaac,

1) Have you tried placing an electrolytic capacitor nearly 22uF across input as suggested?

2) Is the EPAD routed to GND? Have you routed EPAD to GND in inside layers? Could you please share the complete PCB layout?

3) Please probe VIN voltage across the input capacitor in single trigger mode around 60V and share with us. Keep the y axis setup at to show up to 120V.

Regards,

Arpita

0 ARPITA NATH 8 months ago in reply to ARPITA NATH

TI__Expert 6392 points

Hi Isaac,

Please let me know if the issue has been resolved. is there any update?

0 ARPITA NATH 8 months ago in reply to ARPITA NATH

TI__Expert 6392 points

Closing this thread due to inactivity. Please feel free to reopen again if you have any update.

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LM5013: Part burns always at the same spot