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LM22673: LM22673

user5006944
Intellectual 630 points
Part Number: LM22673

LM22673 in the temperature -40 to 70 degrees under the load or not load the test, there will be no damage, when the standstill after the run to take the test at room temperature, there will be damage to the situation, found ss pin and ground short circuit, resistance 5 ohms , The occurrence of such a situation is also accidental, would like to ask what is the reason.

I want to know the detail internal of SS PIN.I would like to analyze the reasons or ask you to help analyze the reasons.Thanks.

  • 0
    TI__Expert 4100 points
    Hello,
    From your description it is very hard to tell what could be possible cause for behavior you observed.
    Also the schematic you attached is not legible and it is very hard to see component values. If you could attach higher resolution schematic that would be helpful.
    As far as internal working of SS pin is concerned, please refer to device datasheet for detailed description.
    Regards
    Brani
  • 0 in reply to user5006944
    TI__Genius 11085 points
    The schematic looks ok. Note that 18V to 15V with 1.5A load current may not be able to be supported by LM22673. The switchng frequency is 500kHz and Toffmin-max is 300ns. So duty cycle max is 85%. With losses at 1.5A, it may need more than 85% duty cycle to keep 15V output.

    The only reason SS could be damaged is some higher voltage appears on the pin higher than the Abs Max 7V. I cannot tell why that might happen from the schematic. We can review your board layout if you'd like to send it over.

    Regards,