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TPS7A91: Output accuracy in temperature

Part Number: TPS7A91

Hi,

I am characterizing the LDO TPS7A91 using a thermal chamber.

Setting a temperature range between 20 and 140 degree Celsius,  I am seeing that the output voltage accuracy, respect to the output voltage value at 25 degrees, is about 3% when the temperature reaches 80 degrees.

To define Vout , I am using 0.1% tolerance resistances with 25ppm of temperature coefficient. For this reason, I was expecting to see output accuracy < 1.7% in all the temperature range.

Could you have any explanation why is this happening? Do you have performed any test that guarantees the accuracy of the component in all its temperature range?

My conditions are the following:

Input voltage=5.5V

Output voltage (nominal)=3.4V

Output Load=22 ohm

Regards

Michele

  • Hi Michele,

    TPS7A91 has an accuracy specification of +/- 1% over temperature.  This specification does not include the external resistor divider tolerance (per footnote 1).

    Could you help me understand how you are making your measurements? Is your measurement 3% high or low?

    Would you be able to provide a scopeshot with Vin, Vout, Ven, and Iout?

    It looks like you attempted to add an image.  Please refer to the following on how to insert an image on E2E:

    Very Respectfully,

    Ryan

  • Hi Ryan,

    Thank you for giving your support.

    These were the images I was trying to attach:

    I haven't taken so far any image from the oscilloscope during the test.

    Measurements have been taken by KEYSIGHT 34972A + acquisition module 34902A.

    The resistors used to set the Vou have a 0.1% of tolerance and 25ppm of thermal coefficient.

    Regards

  • Hi Michele,

    Thank you for the additional data. I apologize for my delay in responding (I was out of office).

    One thing I would like to confirm is your nominal Vout. Is it 3.3 V or 3.4 V? Your initial post states 3.4 V; however, the calculations appear to be based off of a 3.3 V output.

    Very Respectfully,
    Ryan