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LMZ14202: LMZ14202 issue

Manai Oussema
Prodigy 150 points
Part Number: LMZ14202
Other Parts Discussed in Thread: LM2575

Hello everyone,

I requested a sample of the LMZ14202 in order to try its performance, so i prepared a prototype board for it in order to test different output voltages( i used a potentiometer to vary the feedback) with different input voltages( mainly 12V and 24V). Unfortunately, when i powered the circuit the IC gave me 5V for a few seconds then it was blown up. I couldn't find an explanation although the circuit is very basic (typical application of the datasheet). Attached, the schematics of the board and a picture of it.

Thank you in advance for any help.

  • 0
    TI__Mastermind 18940 points
    Hello Manai,

    Apologies for the delayed response.

    Normally you would use low ESR ceramic capacitors on the input and output. Can you put a 1-10uF ceramic cap in parallel with the input electrolytic capacitor?

    Have you tried replacing the part? If yes, do you get a consistent failure?
    Do you have any oscilloscope images of the device input voltage when you power up?

    Regards,
    Denislav
  • 0 in reply to Denislav Petkov
    Prodigy 150 points

    Thank you for your reply Denislav,

    now i added the two 10µF ceramic capacitors in the input and the output, and i also removed the potentiometers and replaced them with fixed resistors for the voltage divider in order to have 3.3V output. I tested it with a 200mA load and it worked fine. I still don't know the source of the problem.

    By the way, i need a technical advice if you are ok. I'm doing this test in order to replace the power input stage of the boards i design, the current IC i use is the LM2575 (and with its necessary components). The reason for me to make this change is to get rid of the inductor (both, from the PCB to reduce input stage footprint, and to reduce the hustle of choosing the proper inductor that matches with the needed current). So what's your opinion about that? and thank you in advance.

    Best regards,
    Oussema.

  • 0 in reply to Manai Oussema
    TI__Mastermind 18940 points

    Hello Oussema,

    I would suggest trying our power designer tool (

    )

    You can input your power requirements and the tool will provide you with several solutions that fit your power needs. It will calculate the necessary BOM components for you. 

    Cheers, 
    Denislav