I am trying to choose a low dropout linear regulator to partially smooth the output of a dual rail SMPS I'm using to power analog circuits. I'm confused about the difference between the specified RMS noise and the PSRR of LDOs. Here is an example from a datasheet I have been looking at.
If my SMPS were to have 10 mV @ 1MHz of ripple on the positive output, and I used the device detailed above, should I expect .8uVrms of noise on the output, or would the SMPS ripple be attenuated by 76 dB and appear on the output. The device I'm taking these numbers from is the LT3045, datasheet here.
Also, I understand that the specifications listed in the features section of the datasheet are best-case device parameters, and that a much closer inspection of this LDOs documentation would be required to effectively utilize it. I don't plan on using this particular chip, as I'm just looking for information on how to use these figures found in all LDO datasheets.