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TPS7A49 / TPS7A30 resistive divider current

Alexander Uvarov
Intellectual 300 points
Other Parts Discussed in Thread: TPS7A49, TPS7A30

Hello!

I use TPS7A49 and TPS7A30 to provide bipolar supply. The output voltage is adjusted by the R1-R2 divider (see datasheet, p.11 or 12) and it is noted that current of this divider must be equal to or greater than 5uA. The question is how much could this current be?

For example, I calculated values for Vout=+5V: R1 = 5.1k, R2 = 1.6k. The current in this case I = 746uA. Is it normal for TPS7A49 or can destroy the scheme?

Regards, Alexander Uvarov.

  • 0
    TI__Expert 3300 points

    Hello Alexander,

    Thank you for your post. This current through the resistor divider will depend on the value of your resistance that you choose and you have calculated it correctly in the example you posted. Also keep in mind, the leakage through he F/B pin is maximum 100nA for the TPS7A49 so this will have to taken into account. The LDO will work fine, but if you want lesser current through the divider, you could use larger resistances but Vout/ (R1 + R2) should always be greater than 5uA as stated in the PDS. All current that the F/B cannot sink, will just slow to GND. Hope this helps.

    Regards,

    Krtik

  • 0 in reply to Kartik Sinha
    Intellectual 300 points

    Yes, Kartik, it helps.

    Thanks a lot for your reply! The question is solved.

    Regards,

    Alexander.