>> Have a browse around the Linear Technology web site. ISTR they do some
>> single cell boost chips - and they provide samples.
>>
>Something like this?
>http://www.linear.com/pc/productDetail.do?navId=H0,C1,C1003,C1042,P1901
>
>I'm not very experienced with switchers :) I need 3V out at least, 1V
>input, 250mA output. Looks like the circuit on p.13 might do?
>http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1042,P1901,
D2814

That could be a possibility, but also look at LT1615 (1.2 to 15V input,
ThinSOT package), LTC3400/3400B ((0.85 to 5V input, ThinSOT package),
LTC3401 (0.5 to 5V input, output 6V max, MS package).

As to not being experienced with switchers, choose a recommended coil and
capacitors from the suppliers recommended in the datasheet, and layout the
pattern as they recommend, and there should not be much more to it.

I'm currently looking to have a play with the LT3470 step down switcher,
which does 4 to 40V input, and outputs up to 200mA with a total of 8
components including the IC. Seems like a real nice chip to use as a 78xx
replacement in a lot of things where one is getting marginal because of heat
dissipation. The whole thing could be built on a PCB that became a 78xx with
low dissipation. ;)

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