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Original question:

TPS74401: Difference between TPS74401KTWT and TPS74401KTWR

TPS74401: can 74401 support 3.05A load current?

BX27
Genius 3900 points
Part Number: TPS74401
Other Parts Discussed in Thread: TPS7A85A

Hi.

We use TPS74401 for 1.23V convert to 1.03V output. estimated max load current is 3.05A.  a little exceed the 3A rating of 74401. We do not hope to introduce a new 4A/5A LDO into our company library.

is it possible for 74401 to support 3.05A？ any caution for hardware design？Thanks，and have a good weekend.

  • 0
    TI__Guru 55940 points

    Hi Yi,

    It is important to recognize that TPS74401 was designed, tested, and characterized for a maximum output current of 3 A.  As your application will be beyond this region you may or may not achieve the performance as depicted in the datasheet.

    Due to your low headroom (Vin - Vout), your application is at risk of entering dropout.

    We highly recommend using an LDO that is rated for above 3.05 A such as TPS7A85A.  

    Very Respectfully,

    Ryan

  • 0 in reply to Ryan Eslinger
    Genius 3900 points
    Hi Ryan,
    I checked again, we use 74401 in several config, such as 1.23V--->1.03V, and 3.5V--->3.3V, and our V_BIAS for all 74401 is 5V, VQFN package, so the VDO max is 195mV at 3A load. I think it should be ok.
    I look into TPS7A85A, its VDO(max) is larger than 0.2V, unfortunately, our Vin can not be changed already , so all we can do is to choose a very low VDO LDO like 74401, and we choose Vin-Vout=0.2V to minimize power loss on LDO.
    Now return to 3.045A question. We may need to adjust load distibution, to reduce the load of single 74401 under 3A.
    Thanks again.