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TPS7A11: PSRR Spec question

Seokmin Hong
Prodigy 10 points
Part Number: TPS7A11

Hello, I am going to use TPS7A11 LDO for my system.

LDO's PSRR is important factor. And in the datasheet,  there is only TYP spec of PSRR.

Doesn't PSRR has Min or Max Spec? There is no defined Min or Max Spec of PSRR.

I think there should be some variation at samples.

For example Normal Accuracy spec is -0.5% to 0.5%. Like this I think PSRR could be changed at sample to sample.


Could you tell me min or max range of PSRR for this LDO? (Other all ti's LDO has only typ.Spec of PSRR.)

ex. -5%~5%, -10%~10%?

Thanks.

  • +1
    TI__Genius 14245 points

    Hi Seokmin, 

    You are correct that there can be some small amount of variation in the PSRR performance from part to part, however the part to part variation tends to be VERY small. 

    In the industry LDO's generally do not specify min/max values for PSRR. At TI the reason we don't specify a min/max value is because this is an extremely noise sensitive measurement and it is not conducive to being measured directly in a manufacturing environment. As you can imagine the manufacturing test floor can be a noisy environment (EMI) and the parasitics introduced by the sockets, cabling, test hardware, etc... also negatively affect the ability to accurately capture transient performance. 

    To give you a sense of the amount of change to expect, I have measured the PSRR of MANY LDOs over the years and I can tell you that generally we don't see more than 1 or 2 dB when comparing part to part variation, even when remeasuring units manufactured many years after the original data was taken.  

    Kyle Van Renterghem

    Applications Manager

    TI LDOs