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TPS7H1101A-SP: Feedback Terminal Voltage (Vfb) End of Life Ranges

BRANDON BURGETT
Prodigy 60 points
Part Number: TPS7H1101A-SP

Hello, 

I was looking to see if TI had any information on how the Feedback Terminal Voltage varies as the parts age. Right now our worst case analysis is failing due to our estimate of how this parameter will change over the duration of the mission. 

If there is some information on the worst case Feedback Terminal Variation per year (or any other unit of time) or even some test data from some actual parts or data from other projects if those are shareable would be welcomed. We might be able to use some data here to bring in our estimates of how much the voltage could and get some more confidence in the design over the course of a couple years. 

Thanks,

Brandon 

  • 0
    TI__Expert 7655 points

    Hi Brandon, 

    I can  check what data is available and get back to you.

    What values are you currently using for your worst-case FB voltage? Datasheet min/max, estimates within those parameters, or extrapolations that are added on top of the datasheet min/max?

    Thanks,

    Sarah

  • 0 in reply to Sarah Koch
    Prodigy 60 points

    Hi Sarah, 

    For the worst case FB voltage we have an initial tolerance of +/- 0.011 V. 

    The end of life contribution ends up at - 0.03653 V and +0.03788 V. I see the note from our parts specialists where they assume 1% at 1000hr, 125 C test. So it is estimated at least partially, and extrapolated from some shorter test, they assumed it would degrade linearly. For reference the Service life for this estimate is 112 months, minimum temperature of -35 C and maximum of 80 C with a radiation dose of 12 krad. 

    So it's a combination of the initial datasheet values and the extrapolation based on our environments we will  be operating in. 

    Thanks,

    Brandon

  • 0 in reply to BRANDON BURGETT
    TI__Expert 7655 points

    Hey Brandon,

    Looking at the SMD for this device, I can see that the Feedback Pin Voltage parameter is covered under the Group A Subgroups: 1, 2, and 3. 

    This means that the min/max electrical end-points in the SMD (which match the datasheet min/max in this case), will also include Group C test. So one would not need to add additional end-of-life contribution to the min/max for the QMLV-grade device if they are basing the aging estimates for their mission on Group C test definition of 1000hrs @ 125C. 

    I am less clear on whether your mission time/temp profile would fall within the extrapolated mission profile that Group C is meant to emulate, so please feel free to clarify and let me know if further support is still needed.

    Thanks,

    Sarah