Can anyone explain why the two capacitors (C8, C9) in the CLC input filter are set up the way that they are? The screenshot is from this reference design:
I will provide some more context to my question:
I understand that there needs to be a smoothing capacitor on the output of that full-wave bridge rectifier to smooth rectified DC voltage. A rule of thumb of 2 - 3uF per watt of input power yields a value of 135uF - 405uF for Cin.
I also know that there needs to be an LC input filter to help mitigate differential-mode EMI.
According to TI's AN-2612 (linked below), the LC values are chosen based on equations outlined in section 4.2.
I cannot for the life of me figure out how we end up with those capacitor values (or inductor values for that matter) in that configuration. Can anyone offer their expertise?