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TPS62110HT, what is the drift ?

richard payne
Genius 4640 points
Other Parts Discussed in Thread: TPS62110-HT, TPS62110, TPS40200

Hi

I have been evaluating the TPS62110HT to 175C and found the VOUT drifted from 1.85V at 25C to 2.05V at 175C for RLOAD 10K to 10R. I tested with VIN=5V, 10V and 12V.

Between 150C to 175C it goes from 1.87V to 2.0V. 

I checked the datasheet and to my surprise there is no drift parameter or chart for HT and EP datasheet.

Is there way to fix the drift issue? it connect to SM320F28335 device.

Regards 

  • 0
    Genius 4640 points
    Bump, any progress?
  • 0 in reply to richard payne
    TI__Intellectual 2385 points
    Hi Richard,

    Looking at the datasheet, the feedback voltage tolerance is from -7% to 8% at 175C. My hunch is something is happening in the feedback circuit. Could you confirm that the resistors you are using are classed for the temps you are using?

    Regards,
    Josh
  • 0 in reply to JoFu10
    Genius 4640 points
    Hi
    I can confirm it in sync with TPS62110-HT (and EP/Q1), R2 = 390K and R1 = 220K, the circuit is essentially similar to the TPS62110-HT.

    The SMD resistor is 150C automotive grade and meta film type. I use same resistor for TPS40200 to 175C and did not drift much as TPS62110.

    There is difference between initial tolerance and drift tolerance. Does the drift repeat in same way for all batch because I could consider tuning R1/R2 to start 1.7V (25C) and drift to 1.9V (175C), but there is no drift chart in datasheet.

    Here the results below.

    Temp, Vout Drift Factor
    25 1.81 1
    153 1.867 1.03
    162 1.892 1.04
    166 1.905 1.05
    174 1.947 1.075
    178 1.973 1.090
    Under 200mA fixed load (restive).

    Temp, Vout Drift Factor
    25 1.829 1.000
    153 1.899 1.038
    162 1.929 1.055
    166 1.944 1.063
    174 1.987 1.086
    178 2.012 1.100
    Under 2mA fixed load (restive).
  • 0 in reply to richard payne
    Prodigy 10 points
    Hi all,

    You might want to look at the FB leakage current in the TPS62110-HT datasheet (2100nA at 175oC).

    regards
    Patrick