... which, I'm sure, doesn't surprise anyone ...


Unless you make statistical observations [incoming inspection] of the products you buy for use in your end-product, I don't see how you can verify anything. It's only those observations that I asked about.


All I asked was information. Presumably, you have, at some point, verified that the devices you use actually meet their advertised specifications.


Nope ... what I wanted was a reading on how well the commercial switcher performs, particularly as compared with its spec's. You know ... "raw" ripple at 10% of rated capacity ... "raw" ripple at 90% of rated capacity ...


... <sigh> ... If only it were that simple. Small switchers generally have an input filter and an output filter, and the units that take AC input have a transformer and filter input, too. As these decay, which happens when the power is turned off, they behave in different ways, certainly not as simply as you describe. Further, it certainly is different from a linear regulator, as I'm sure you can imagine.



I generally don't build my own switchers, though I have done that. I have, however, never encountered even ONE small switcher, on the order of 1 ampere output rating or less, that was (a) actually capable of what its datasheet claimed, and (b) was satisfactory for use with any serious MCU application. I've tried premade boards, modules, etc. They're all, IMHO, WAY too noisy, and regulate far too poorly under conditions of changing load.

Now, you've stated that you use the switching regulator as a pre-regulator for your primary Vcc (3V3) and that's probably a good thing, but I'm curious what YOU have found, since you use these products all the time.

I don't use small switchers, and haven't examined available small commercial switchers in quite some time, but might be taking another look in the near future. I do sometimes use wall-warts as a raw unregulated input to on-board regulators, though I have, in the past, been pretty disappointed with them, too. Since almost all my serious 805x contact is in systems that have existed for 15 years or longer, all of which, so far, have had significant linear supplies on hand, I certainly haven't concerned myself with the use of switchers with 805x's.

I don't, at least so far, care about the filtering you apply. Since you use these small switchers, I figured you could shed some light on what they actually do. What I like or dislike, or what I consider adequate or inadequate, is not really germane to the question. I'm just curious about the observations you've made, and not just about the published claims.

BTW, I do use switchers when practical, just not small ones. Fewer and fewer applications demand the 80 to 100-ampere multi-output supply, though, and fewer and fewer of them tolerate the switching noise ...

RE