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TPS78101: remove VOUT programming resistors?

Anonymous
Anonymous


Hi,

I would like to ask a question on TPS78101.

Page 13 of its datasheet SBVS102B shows how VOUT can be programmed using resistor divider. The reference voltage is 1.216V.

However, if I would to use 1.216V output directly because if falls in the required range of my device, then can both R1 and R2 be removed, and connect [pin FB] directly to [pin OUT]?

This corresponds to (R1=0, R2=∞). But the datasheet also says that higher resistor should be avoided, and R2=∞ is absolutely a "higher" value and perhaps should be avoided.

Could anyone advise here?

 

Zheng

  • 0
    TI__Mastermind 41800 points

    Zheng,

    As you highlighted above, there is leakage in the FB pin of the device. For a resistor divider, this means less current going into the bottom resistor. If the current through the resistor divider is comparable to the leakage flowing into the FB pin, the voltage on the bottom resistor/ FB pin will be inaccurate and this will create an inaccurate output voltage. 

    For the case described above, there is no current flowing through R2=infinity so there is no Vfb inaccuracy.  

    Darwin 

  • Anonymous
    0 Anonymous in reply to Darwin Fernandez

    Darwin,

    This is solved. Thanks very much for the answer.

     

    Zheng