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Original question:

TPS7A84: will 1.3V voltage backflow at the output port affect the chip function?

TPS7A84: 40mA reverse sink current

Jayden Qiu
Intellectual 1285 points
Part Number: TPS7A84

Hi Team,

ZTE uses TPS7A8401A, and they have some question when using this part.

Test condition: Vin=3.3V, Vout=2.5V, Iout=0.5A; RFB_up=30.1k, RFB_bottom=7.44k, cff=0.01uF

After the LDO normally outputs 2.5V, the load will have a reverse sink current of about 40mA, which will cause the FB voltage to be pulled up to 0.54V, and the output voltage will rise to 2.8V. 

Is there any application risk in this way?

Thanks

Brs

Jaydden

  • 0
    TI__Mastermind 18466 points

    Hello Jaydden, 

    The recommended maximum reverse current is 5% of the rated output current, so 150mA for this device. Normally an OR'ing device is used for this kind of application to protect both power supplies. 

    Per the datasheet:

    Best,

    Juliette