> In the latest Maxim flyer is the MAX6971-MAX6976
>
> http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3441
>
> 5V - 72V i/p linear regulator, 300mA o/p
>
> It, or something like it, sounds ideal for the application. I need
> several supplies from an 8V - 30V i/p. Battery charging (both

Data sheet here

        http://pdfserv.maxim-ic.com/en/ds/MAX6791-MAX6796.pdf


Maximum dissipation is 2.66 Watt, derate 33.3 mW/C above 70 C.
Say 2 Watt to be sensible.

30V to 12V allows 2/(30-12) = 110 mA at 30 Vin 12 Vo.

No magic here and no grwat vakue in the part for you.
An LM317 would do about as well.

For 8V to 12V you are going to need some sort of boost converter. 
(Actually 8v to 14V or more for SLA charging.
Bite the bullet, make an MC34063 step up converter of some sort and 
linear regulate its output if you must.

Or best of all a boost buck of some sort so you can handle 8-30 Vin in 
one go.


        RM

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