Is there a Dual Voltage Regulator?

Microchip has a document called 3V Tips ‘n Tricks. It has some options you can chose that will help you.

What you're asking for is pretty common since there are a lot of mixed-voltage IC applications out there with the same constraints (especially the two voltages you listed since most ICs operate off either of those two). Here are two options for you:

• MIC5211-LXYM6 from Micrel should do what you want. It's a dual-output, +3.3V/+5V linear regulator but only can output 80mA.

• TPS767D301 from Texas Instruments if you require more power than that. It has a +3.3V fixed output and an adjustable output which will go up to +5.5V. It can output up to 1A (per supply) and should be able to source most projects that I could think of.

If you require more power than either of these two, it would make sense to go to two separate supplies.

There are plenty of dual regs, but it is often cheaper to use two seperate ones unless you have severe space constraints, as there are many more parts to choose from in single-output versions.