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LMR14030: LMR14030 burn out

Betty Guo
Expert 7300 points
Part Number: LMR14030

Hi,

Customer use LMR14030 in 24V applicaiton, and found that it very easy burn out, the pins impedance are short to ground. 

we measured the Vin voltage waveform and not found it higher than 40V. here is customer schematic, please help review it and give comments.

Vin:24V 

Vout:5V

Iout:0.3A

LMR14030 SCH.pdf

  • 0
    TI__Mastermind 27045 points

    Hi Betty,

    Do you mean LMR14030 was damaged or 5V load was damaged?  it burn out at what condition? 

    What's the P/N of D1? a 10uH--22uH 5A inductor is OK for this conversion, why use 2pcs 22mH inductor? normally the 22mH inductor has quite small current rating, it maybe saturated in this application and cause device damaged.

  • 0 in reply to Andy Chen
    TI__Expert 7300 points

    Hi Andy,

    LMR14030 was damaged, the P/N of D1 is SRM54ALF.

    customer also feedback that the D1 can be damaged sometimes. they made mistake about inductor value. According the eq.10, the induction vaule is about 32.9uH.

    why inductor saturation damages the device?

    thank you

  • 0 in reply to Betty Guo
    TI__Mastermind 27045 points

    Hi Betty,

    The saturated inductor can't limit the current peak during high side FET turn ON, too high current peak may cause EOS damage on IC and diode.