See TL783, from 21.5V to 125VDC input, adjustable output:
http://www-s.ti.com/sc/ds/tl783.pdf
or this:
http://focus.ti.com/docs/search/paramsearch.jhtml?tfsection=param_table&templateId=2&showAssociated=false&familyId=437

Ling SM
> Can anyone suggest a good way of creating a 5V supply (max 250mA) from a
40V
> supply. Most of the simple regulators don't seem to like this high an
input
> voltage.

> Oh and if this is too easy how about generating a +5V supply again
> 250mA from a -40V supply, needs to be able to share the same ground as the
> +40v and -40v supply and must be +5V not -5V.

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