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INA333-HT: High temperature instrumentation amplifier

Antal Soos
Prodigy 70 points
Part Number: INA333-HT

Support Path: /Product/Development and troubleshooting/Find key information on a device/

We are using the INA333-HT with a 20K OHM 0.1% 0.15W  0603  (PATT0603E2002BGT1) gain resistor.

It works fine on room temperature, on the other hand at after 110C  the selected gain and output  signal start to reduce rapidly as the figure bellow illustrates.

The input is corresponds to pin2.

The pin3 input is 2.5V from the divider.

All test point to the  INA333-HT the 210C device not performing above 110C,

 For test purpose we also tested without the capacitors which did not effected the outcome.

Any suggestion?

The circuit is:

  • 0
    TI__Genius 14540 points
    Hi,

    At first glance I don't see anything obviously wrong with your circuit. Are you able to measure the voltage at pins 2 and 3 of the INA over temperature to ensure that each input is within the boundaries shown in Figure 23 of the datasheet. The device is behaving as if the VCM of an input exceeds this window even though your data above suggests otherwise.

    Thanks,
    Christian
  • 0 in reply to Christian Yots
    Prodigy 70 points

    The Problem Solved:

    The reason for the behavior is limited capability of the INA333-HT to drive loads at higher temperatures, over 110⁰C.

    The implemented voltage divider acted as RL=1379 ohm load, which was too much to be driven by the INA333-HT.

    Eliminating the R81 and R80 resistor solved my problem.

    If we assuming a linear behavior over 175⁰C  the load driving capabilities of the INA333-HT are diminishes as the temperature rises.

    It would have save me lots of time if this is emphasized in the INA333-HT data sheet.

    Best Regards,

    Antal