DC-DC power supply

Hi

I am building a portable GPS app. My power source will be 3 AA 1.2V rechargeable batteries that give 3.6V but, some of my parts require 3.3V +- 5%. My app will consume at the most 900mA. I have checked out several DC-DC step-down IC's but the most of them need more than 4V input to give out 3.3V and the current my solution demands. Do anyone know of a solution for my problem? Could a zener diode (3.3V) and some capacitors be a good solution?

You could just use a diode with a lower voltage drop across it.

Although most low voltage logic systems are still not that fussy about how accurately the voltage is maintained. Being only .3 volt over the rated limit shouldn't cause any problems. Its still under the 10% over range limit thats common in most electronics devices.

My Computers system monitor doesn't register a over voltage alarm point until 3.9 volts on the 3.3 volt DC buss.

You could use a low dropout (LDO) linear regulator such as the LT1963A Linear Technology - LT1963A - 1.5A, Low Noise, Fast Transient Response LDO Regulators.

Ok. Thank you for your replays! I will check out the regulator from Linear and also how sensitive my components are to 3.6V.
But aren't the regulator better suited to supply more/"cleaner" current than no regulator?