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LM22676: LM22676 burn up when it power up

aggil liang
Expert 2660 points
Part Number: LM22676
Other Parts Discussed in Thread: LM22674

Hi TI teams,

     When we use LM22676 or LM22674, we design the circuit as below, the FB signal is from the MCP6002. The output voltage is changed following the DAC output signal. 

But when we PP the product, and do test, LM22676 burn up when the system is power up.  The failure rate  is about 10%, and when finish power up , the system is steady. Can you help to check whether the circuit is OK ?  and pls. give some advise. thanks 

  • 0
    TI__Guru 57555 points

    It looks like you have the feedback from the output going through another device.

    The FB input is very sensitive and may be causing some kind of trouble.  I would test

    your boards with the FB input connected through the FB divider directly and see if that helps.

    Also, be sure that the inductor and diode are both rated for the full current limit of the regulator.

    You can return the damged units to TI for evaluation if you wish.