ELEKTOR FORUMS

Hello Sirs.
I working on development of three products who will be powered by batteries.
I'm thinking to use 3x 1,2V NiMh batteries in series. Considering them connected in series, the voltage of the system will be around 3V (when the batteries are almost fully discharged) and around 4.2V (when they are fully charged). I will also need to use these power supplies on USB ports (range 4.75 to 5.25V).

So my actual input range will be 3V to 5.25V.
Considering some tolerances, I will need two kinds of power supplies:

A) Input range: 2,8V to 5,5V. Output: Fixed at 3,3V (capability of 400mA or more)
B) Input range: 2,8V to 5,5V. Output: Fixed at 5V (capability of 400mA or more)

Which IC is recommended to meet these requirements, some ideas? I think some Bulk step-up\step-down converters may do this job fine.
Remembering that input voltage is adjustable (2,8 to 5,5V) and not a fixed voltage.

I checked LM2735's datasheet from National but I continue thinking that input voltage must be stable to obtain a stable output voltage with this IC and thats not the objective of this power supplies.

An easy-to-find IC would be great. From National, Fairchild, Microchip, Texas etc.
Im looking for an IC in SMT package, like SOT23, SOT223 or something similar.

Somebody suggest ICs for this purpose?