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LM5164: LM5164 gets hot

Joe Romine
Prodigy 10 points
Part Number: LM5164

Tool/software:

Hello,

I am trying to design a circuit to accept a variable voltage input between 15VDC and 100VDC. I need to convert this to a regulated 12V output to drive a few LEDs and MOSFET gates. The LM5164 was getting very hot to the touch in my design, and I figured there was a problem with my circuit. So, I created a new board with just the recommended test circuit from the datasheet (see attached circuit). I understand that the datasheet does recommend a specific layout of components and vias to help transfer heat. But should this device be getting so hot it can burn you if it is just driving a single LED using a 24VDC input? Or maybe there is some other TI product I should be using that would run cooler?

  • 0
    TI__Expert 5490 points

    Hi Joe,

    Your Pin 1 GND connection is incorrect. Pin1 is the GND connection for all internal circuits. In your design, you have connected GND pin 1 to GND plane through 100k resistor 

    Please make below changes to your schematic.

    Also, the PCB layout is pretty bad and it can't handle higher current due to PCB trace width. Recommend you to refer LM5164 datasheet layout guidelines for more details. 

    Thanks,

    Nitya