Re: UCC33420 dc/dc converter eval

On 10 Apr 2025 08:48:48 GMT, Uwe Bonnes
<bon@hertz.ikp.physik.tu-darmstadt.de> wrote:

john larkin <jl@glen--canyon.com> wrote:

 
 
My TI rep was being difficult, so I just bought an eval board from
Digikey for $100.
 
It makes a nice 4.993 volt output, but it's wicked noisy.
 
https://www.dropbox.com/scl/fo/8fybyu5l3w4tdgt1y0386/AFunYi9K15UgNpkQzEbYaVA?rlkey=j261b4ca5kc966vq2y03fw0md&dl=0
 
53% efficient into that 0.25 watt load.
 

>
I think this high frequency noise should be easy to filter by some CLC
Filter.

Not really. I need it to be close to the load, and that load is super
noise sensitive. I didn't check, but there is no doubt some
considerable and nasty emitted mag fields too.

In addition to all the high frequency crud, there's the basic burst
and its side effects in the hundreds of KHz range, would would take
giant parts to filter.

There are interesting parts around now that include their own power
isolation. Some are capacitive, not inductive, so may be better.