Tool/software:
Dear WEBENCH experts, when using the input filter functionality of your tool, I noticed that it has problems with ceramic Cb_inpflt: In spite of having an easily adjustable Rd_inpflt in series, the tool will require the ESR of Cb_inpflt to be larger than typical MLCC will provide. For example, it would require the ESR of Cb_inpflt to be between roughly 10 and 300 mOhms, preferably 150 mOhms, with a 150 mOhms Rd_inpflt in series. Given that 10 mOhms are a lot for a ceramic capacitor, I get very little choice of ceramics and most suggestions will be OS-CON or tantalum. I believe it would be possible to set a lower ESR limit of zero for Cb_inpflt by making slightly higher Rd_inpflt the default.
Another interesting option would be to select whether or not the input filter should have those two components at all. Simulation results reported by your tool are not much worse if I "disable" the damping by manually setting Rd_inpflt to a very large (megaohms) value. I could then omit both components in real life for a reduced footprint solution with a simplified, but not completely absent input filter.