LM25088: The MOSFET is very hot when the output is below -11V@2A

aggil liang

Part Number: LM25088

We design a negative circuit using LM25088. The spec is Vin=24V, Vout= -10 to -18V @1.5A.

When the output is below -11V(-11V, -12V, -15V, -18V) with no load, the MOSFET AO4354 is very hot. the temperature is above 80℃. when it is on 1.5A load at with any VOUT, the temperature of MOSFET rise up 110 ℃ quickly. We disable it.

Can you check the schematic to improve it ?

over 6 years ago

0 Katelyn Wiggenhorn over 6 years ago

TI__Genius 11040 points

Hello,

Thank you for sharing the schematic. Would you be able to also send the layout for this design for review?

Thank you,
Katelyn

0 aggil liang over 6 years ago in reply to Katelyn Wiggenhorn

Expert 2660 points

Hi Katelyn

FYI

CK3-CF3_Print_Board_V0.1_190228gerber.rar

0 Katelyn Wiggenhorn over 6 years ago in reply to aggil liang

TI__Genius 11040 points

Hello,

We will be in the process of reviewing your board today, and we will provide feedback by tomorrow.

Best Regards,
Katelyn

0 Katelyn Wiggenhorn over 6 years ago in reply to Katelyn Wiggenhorn

TI__Genius 11040 points

Hello,

What program did you create or view these gerber files with?

Thank you,
Katelyn

0 Katelyn Wiggenhorn over 6 years ago in reply to Katelyn Wiggenhorn

TI__Genius 11040 points

Hello,

I was able to find a program to open the layout files. Thank you for sharing.

I do not see any thermal vias on the design. It is important to have thermal vias from the DAP and around the device in order to aid in heat dissipation. This will help keep the board running at a cooler temperature. Also if possible, you could connect the DAP to a ground plane on the top of the device in order to aid in heat spreading.

Best Regards,
Katelyn

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LM25088: The MOSFET is very hot when the output is below -11V@2A