On Fri, 13 Sep 2002, Alan B. Pearce wrote:

>>Also examine the simple switchers from National and the
>>ancient 78S40 and other chips.
>
>
>The MC34063 seems to be a cut down version of the 78S40 so it fits in an 8
>pin package. It is also multi-sourced, so should be readily available at a
>good price. In the UK RS Components has them for 56p 1 off, and a tube of 98
>set you back under GBP30. These prices are for the SM version. This is not
>that different in price to a 7805 1A regulator in TO220 package, which would
>then need to have legs bent and be screwed down to mount on board.

And a heatsink which may be more of a pita in a small device that cannot
get hot. There remains to be seen how this works out noise-wise. I have
mixed experiences with 78S40. Unless you guarantee a minimum load it will
be 'chaotic' <g> in operation.

Peter

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