Hi Team,
Our customer is using the LM25088 with the following specifications.
Input voltage: 24V
Output voltage: -5V
Output Current: 6A
However, the device failed when the load current is more than 1.5A. According to our customer,
"This circuit works fine up to -5V/1.5A. When it is loaded more than 1.5A, the output voltage drops and the integrated burns.
(The VCC and BOOT pins of the this IC are short-circuited. That is, the diode in the integrated is broken.)"
Please see attached schematic diagram and PCB layout.
Upon checking the layout, I noticed that the pad of the device don't have thermal vias that will dissipate the heat from the device to the board. The board also don't have a large ground plane to connect the vias. Hence, I concluded that this is a layout issue.
The second concern of our customer is the noise coming from the coil. According to our customer,
"In addition, when I load the circuit more than 1.5A, coil whine is heard. The circuit is not working properly when coil whine occurs. What could be the reason for this?"
Regards,
Danilo
