In a project, I am using the PTN78020H power supply, and it has a recommended circuit (from the datasheet linked above) that looks like this:
Now on the input, it requests a massive 4 x 4.7uF ceramic capacitors. I've had a look around and haven't found any place selling through whole ceramic capacitors in values anywhere near that.
Typically a ceramic cap is used to filter high frequencies, and electrolytic have much worse performance, so I don't want to switch all the input caps to electrolytic, but would it be feasible to, say, use 10uF electrolytic and 1uF ceramic?
Tantalum caps come in the 4.7uF capacitance range, and I believe have better performance than electrolytic?
My question is pretty much: Assuming I can't get hold of 4.7uF ceramic capacitors, what should I do?
Best Answer
Your assumption is incorrect. 4.7 uF ceramic capacitors are widely available. Mouser, the same site where you seem to have found your power supply, has on the order of 100 listings for through hole 4.7 uF ceramic capacitors, and over 1000 for SMT.
So the best thing to do would be to simply purchase 4.7 uF ceramic capacitors, as recommended by the datasheet of your power supply.