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LM43600: Is the 2A variant a direct replacement for the 0.5A variant ?

gilles mourier
Prodigy 210 points
Part Number: LM43600

The LM43600PWPR or LM43600QPWPR-Q1 is used in some of our products to convert 28V to 5V or 3.3V.

At the moment, our purchasing department cannot source the 0.5A variant but are able to source the 2A variant: LM43602PWPT.

I have compared the characteristics of the 0.5A variant to those of the 2A variant and I think the 2A variant can be a direct replacement for the 0.5A variant.

Am I right in thinking that? Are they any risk in doing that?

Thanks in advance for your support.

  • 0
    TI__Genius 13735 points

    Hi, Gilles,

    Thank you for the posting, Yes your understand is right for this pin 2 pin device to be alternative. Please verify if inductor need to change, you can refer to DS Table 2. L, COUT and CFF Typical Values, for the components check , or if need you can also share you SCH for us to review .

    Elena

  • 0 in reply to Elena Gao
    Prodigy 210 points

    Hello Elena,

    Thanks for your reply.

    Could you clarify why using the 2A variant of the switcher instead of the 0.5A would require a change of the inductor?

    Is there a risk in using a 2A switcher with 0.5A inductor (the load remains unchanged compared to the 0.5A switcher)? 

    Gilles

  • 0 in reply to gilles mourier
    TI__Genius 13735 points

    Hi， Gilles，

    To ensure the optimum transient response and loop stability of the converter, a inductor is calculate with max loading and max vin condition, . If they change it to another value, they should check the performance of the device for all their operating conditions. 

    Elena

  • 0 in reply to Elena Gao
    Prodigy 210 points

    Thanks for your answer. Our products using the LM43600 are not a new design, there is no reason for us at this stage to change inductor values which have been used for years without problems.

    I would like to evaluate what is the risk in using the 2A variant instead of the 0.5A variant as our purchase department can source the 2A but not the 0.5A. Inductors are rated to the maximum load (<200mA) but their saturation current remains lower than the maximum current of the high side switch especially for the 2A variant:

  • 0 in reply to gilles mourier
    TI__Genius 13735 points

    Yes, truly understand your concern, suggest once you change device, check the load transient response to confirm the loop is stable, and verify theVout ripple and SW waveform stable if you do not want to change external components.

    Elena