VMP3203-5V High Efficiency DC-DC Module

Pros: Compact and simple. Draws practically no current by itself (when not under load). 3A output?! Pretty good price. Virtually no heat dissipation, so no heat sink needed.

Cons: This module was obviously designed as an SMD (Surface Mounted Device) to be soldered directly to a PCB (Printed Circuit Board), so it does not have any pins or connectors. Soldering wires directly to it is somewhat tricky, but not impossible. I stuck the whole thing with the wires soldered to it into a heat shrink tube to protect it.

Other: With so many devices that use 5V DC (practically anything that powers through USB ports, plus a lot more) this thing has many uses!

Pros: - compact
- super efficient
- powerful
- stable, clean power

Cons: - price (?)
- requires 5V on enable Input
- not really 3A (debatable)

Other: Buy this if you need a really small, yet powerful supply. Don't expect the unit to work right away, you need to put a logic level signal (5V) on the EN-Pin to turn it on. this can be easily achieved by a large resistor (10-47k doesn't really matter) and a 5V zener diode. Some may argue about the price but i think it's fair considering i'd probably pay 5 times as much if i bought something similar around here in a shop.
Oh, and don't forget the capacitor on the output. Instead of the suggested 47uF from the datasheet, i'd recommend you not to go any lower than 220uF. What's more important: Use ONLY low or super-low ESR types! "Normal" types will get very hot or even blow up due to the intense ripple current. And if they don't they'd still waste a lot of power impacting your efficiency considerably.

Pros: No heat till 1 Amp power output, seems the claim of high efficiency is true. I don't have a need to use more than 1A at this moment I can charge Vosonic VP-8360 that requires at least 500 mA, MP4 player, Nokia phones. I was also able to power up USB HD that require more power than what the USB port can provide

Cons: Can not charge iPhone 4. iPhone 4 didn't even give any indication that it is charging. multiple cables tried. Those cables works in charging iPhone 4 via the USB ports of notebook.

Other: It is a working solution providing 5V output at least for 500 mA. Just be careful if you want to charge iPhone 4. Not sure why it works with other devices needing 5V