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TPS7A83A: Vdropout, output noise and PSRR

Part Number: TPS7A83A

Hi Team,

Customer would like to see the real test data with their condition to make sure no problem for Vdropout, and output noise and PSRR performance. Would you please help to verify and note what's the proper Cnr/ss, Cff, and Cout you use?

- 4.5Vin(with same Vbias) to 4.1Vout/1.2A

- frequecy range 100Hz - 10MHz

Thanks.

Allan

  • Hi Allan,

    The Noise and PSRR curves in the datasheet are real measurements and specify what conditions and capacitors are used.  Attached is a few slides which show how application conditions impact noise and PSRR:

    3872.Application Conditions Impact on PSRR and Noise.pdf

    You will note in the presentation that a plot with the same dropout will yield similar PSRR.  As such the light blue line in Figure 6 gives you an indication of your application's PSRR at 2A, but when adjusting for the lighter load current, we would expect your application's PSRR to be similar to the green line.

    You will see in the presentation that for noise, it is the output voltage yields the biggest impact.  Figure 10 shows that the noise for output voltages from 3.3 V to 5 V are very similar.

    Very Respectfully,

    Ryan