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LTM4622A parallel combination issue

Dear Sir/Mam,

Please find the attached schematic for your reference.

Input Voltage: 16VDC

Output Voltage Required: 12VDC/4A

I have designed a schematic as per figure No: 28 in the LTM4622A datasheet.

But when I connect the input supply, it get burned.

Please let me know if I am doing anything wrong.

Thanks in advance.


  • Hello Akarsh,

    if part gets burn at start-up/connecting input supply: please see following document:

    Regarding the desired 12V@4A output load: Figure 29 is a better example for such high output voltages, but figure 28 fits in principle as well.

    And please start using common sense on power numbers:

    12V*4A are 48W!

    Even with very good 94% efficiency you end up with 3W power losses in the tiny modul! Please check the derating curves and thermal impedance in the datasheet to get a number for maximum ambient temperature or possible reduced output current capability.

    kind reagrds


  • Hi Mark,

    Thanks for your reply.

    But we are testing it on a room temp. and we haven't connected the output load.

    We are checking the output without load.

    And when we turned on the input regulated supply(Agilent DC Power supply), it get burned.

    So, My question is that what's the issue with the schematic for parallel application.

    I know, it would not give me 4A  exact output but atleast it should work first then will measure the max current. 

    So, Please suggest me some solution.

  • Hello Akarsh,

    as stated above the AN 88 describes a possible scenario where a DC/DC regulator gets burned/destroyed by voltage transients at the input. Please try following: 'turn-on'/connect  the Agilent DC supply at 0V and increase input voltage manually resp. slowly till the desired input voltage. If your circuit survives this test I bet  AN88 will offer you a solution.

    kind regards