Re: National switching regulator LM2678


<acctforjunk@xxxxxxxxx>

** Don't top post.

Bad usenet ettiquette.

Looks hostile and offensive.


I finally figured it out. I needed more filtering on Vin. I put a
0.47 uF right across the power pins.



** A 0.47 uF what ???

The data *** showed 3 x 15 uF electros.

Got them too ?


Read my original post: "a 1000uF cap at the input".


** Does not answer my question.


Switchers Made Simple 6.24 specifies a 1000uF cap for nearly any
voltage/current combination,


** For what ?

100 / 120 Hz ripple filtering ?


and this will eventually go into a
variable power supply. The 0.47uF is just for "up close and personal"
bypassing.


** Again - a 0.47 uF what ??

Film, tantalum, electro ???

If you had a 1000 uF electro fitted close to the device, a 0.47 uF would do
SFA - whatever type.




........ Phil








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