Favorite 3.3V regulator

With more and more stuff to connect to Arduino at 3.3V, tapping off of the USB is getting less handy.

What is everyone’s favorite, bullet proof, probably LDO, 3.3V regulator?

I’ve made notes on using the TI UCC283-5 and UCC283-3 low drop out (LDO) voltage regulators.

I used the UCC283-3 with success on my Netduino project.


Disclosure: The ones I used were from TI’s sample programme.

I don’t have a favorite, haven’t used them enough, but I have ran into several.

If I did have a favorite, it’d probably be a 7833, as it’s a drop-in replacement for the ubiquitous 7805. Not LDO, though, and not exactly common.

I have used a 2985 (or was that 2981?) 3.3V fixed. It’s a bit weak at 150mA (at least the SOT-23-5 version I used was).

I received some LP2950s in TO-92 a couple of weeks ago, but haven’t used any yet. LDO, but only 100mA.

The LM2940 is a nice LDO replacement that’s pin-compatible with the 78xx, available in 5v and 3.3v fixed versions, among others.

Of course, there are always the adjustable regulators; I’ve got a couple of LM317’s in service at 3.3V.


I like using Microchip’s MCP1700-33 LDO regulators when working with the Arduino. I use the TO-92 part so it’s small with a max of 250mA. It works well for powering most of the 3.3v sensors and parts I’ve used like XBees and other radio modules. It has a max input of 6.5V though, so I only connect it to 5V on the Arduino (not “Vin”).

When I need more current, I use the LD1117v33. It’s a LDO TO-220 regulator.