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LP299 Missing datasheet information (PSRR)

Nikita Gorshkov
Prodigy 165 points
Other Parts Discussed in Thread: LP2992

Dear colleagues,

Can you please advise on the following issue:

We noticed that the LP2992 is promoted as having High PSRR in this guide:

http://www.ti.com/lit/sg/slyt228g/slyt228g.pdf

However, the PSRR is not quoted in the actual datasheet. Is this known or available, please?

Kind Regards,

Nick

  • 0
    Mastermind 7395 points

    The PSRR is published on the datasheet as the Output Voltage Line Regulation

  • 0
    TI__Mastermind 22610 points

    The LP2992 probably made the marketing guide based only on 'Low Noise' in the data-sheet title, not for 'Low Noise AND High PSRR'

    The LP2992 data-sheet has numerous PSRR Typical Performance curves labeled 'Ripple Rejection'. PSRR is affected by the Cout value, the Cbypass value, Vin value, and Vin to Vout differential.

    The ~typical~ PSRR with Vin=5.0V, Vout=3.3V, Iout=50mA, Cout=10uF, and Cbypass=0, at f=1kHz would be about 60dB. This would also probably be the optimum value, as PSRR can be lower depending on the component values and the application.

    The data-sheet specification for "Output Voltage Line Regulation" could be interpreted as PSRR at f=zero, or some very low frequency well off the left side of the Ripple Rejection Typical Performance chart.