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TPS7A4501-SP: Vadj query

David Court
Prodigy 10 points
Part Number: TPS7A4501-SP

Tool/software:

Dear TI team,

I was looking through the TPS7A4501-SP data sheet and noticed Vadj is stated as 1.174V minimum, 1.246V maximum across the full operating range. I assume this then scales linearly so that for a design with Vout=3.3V for example the variation in Vadj could lead to an output of anywhere from 3.202V (1.174*3.3/1.21) to 3.398V (1.246*3.3/1.21), i.e. +/- 98mV deviation from nominal.

Is this assumption correct? Looking at the value stated for 25°C only gives a +/- 14mV variation in Vadj from typical, is it right to assume this is device-to-device variation with the additional 22mV variation for the full range being due to temperature?

Kind Regards,

David Court

  • 0
    TI__Genius 12150 points

    Hi David,

    Your approach for approximating the influence of Vadj variation on the VOUT set voltage would be roughly valid. Other factors like Iadj could be considered depending on your needs.

    Using the min/max of our datasheet specs is often a fairly conservative approach since they account for part-to-part variation, full temp range (unless specified as single temp only), operating voltage/load (depending on stated test condition), rated TID (according to SMD), and include some statistical guard-banding on top of that. 

    David Court said:
    Looking at the value stated for 25°C only gives a +/- 14mV variation in Vadj from typical, is it right to assume this is device-to-device variation with the additional 22mV variation for the full range being due to temperature?

    Yes, the 25C test largely highlights part-to-part variation at a single temp, VIN, and load. The Full Range test shows the influence of temp, line, and load corners. We also have a Typical graph showing the influence of temp on one measured unit to give insight into how Vadj varies with temp. 

    Our TID report can also be referenced as it shows measurements pre- and post-radiation across VIN and IOUT corners for Vadj at 25C. This may be a useful datapoint if your analysis of the tolerance is a bit tight for your design goals. 

    Thanks,

    Sarah