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LP3874-ADJ: LP3874ES-ADJ/NOPB

ikon
Genius 5355 points
Part Number: LP3874-ADJ
Other Parts Discussed in Thread: TPS7A85A, TPS7A84A, TPS7A83A, , TIDA-01232

Hi Support,

If I need to output more than 0.8A of current, can I connect 2 of these LDOs in parallel? Any risk or issue?

Thanks.

  • 0
    TI__Guru 55940 points

    Hi Ikon,

    While it is possible to parallel two LDOs, is there a reason you do not want to use an LDO with a higher current rating such as TPS7A83A, TPS7A84A or TPS7A85A?

    Here are a couple of TI-Designs that go into methods of paralleling LDOs.  You should be able to use the same methods with LP3874-ADJ.

    Very Respectfully,

    Ryan

  • 0 in reply to Ryan Eslinger
    Genius 5355 points

    Hi Ryan,

    Can you check if I can do so without the use of Op-amp? The 2 output 4V8 is connected together to output to load. The same 5V_Main is used to supply the 2 LDOs. See schematic below.

    The document for current sharing dual LDO did not state the Bias voltage for the Op-amp, but if it needs to be greater than 5V, it is not feasible as I only have a max 5V source.

    Thanks.

  • 0 in reply to ikon
    TI__Guru 55940 points
    Hi Ikon,

    Please note that TIDA-01232 does not use an op-amp. The schematic you have will only work if the reference of both LDOs and your resistor dividers are exactly the same values. This is statistically unlikely due to some variation in manufacturing. The variation will result in one of your LDOs having an output voltage slightly higher than the other. The LDO with the higher output voltage will bear the full load of your application.

    Due to your voltage constraints, I highly recommend you consider TPS7A83A. This is a 2 A LDO that will be capable of handling your full load by itself. You will be able to reduce component count and save on board space over the paralleling approach.

    Very Respectfully,
    Ryan