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TPS77001 FB pin leakage current vs recommended resistive divider

lech lachowicz
Prodigy 70 points

The FB pin leakage current is specified as +/-1uA on page 5 of the datasheet.  On page 13 of the data sheet the recommended divider current is 7uA.  Using 0.1% tolerance resistors and the internal TPS7701 FB reference (+/- 3%) the worst case output voltage +/- tolerance is 11%.  Is there an error on the datasheet for the FB leakage current or is this an acceptable output voltage tolerance?

 

3.1V supply Nominal minimum maximum tolerance tolerance
divider,vfb 3.12885 2.782541783 3.475892419 -11.0682269 11.09169244
leakage vfb 1.00E-06 -1.00E-06
  • 0
    TI__Mastermind 41760 points

    Hi Lech,

    This is a much older IC and though it does not say in the parameter or test conditions columns of the specifications table, the 3% output voltage accuracy includes variations in the load, temperature, and recommended resistor divider on page 13 of the datasheet (i.e 1% resistors with 7uA through the resistor divider) for the adjustable version.

    The 1uA feedback current spec is an upper limit due to test capability. It is difficult and expensive to test for the real feedback current because it is much much lower.

     

  • 0 in reply to Darwin Fernandez
    Prodigy 145 points

    Thanks Darwin!

    I was curious how this was tested and see that you and Jeff are both saying there is a min limit to the ATE's tester capabilities. Hope you are doing well!

    Take Care,

    Michael