Adafruit Industries LM3671 3.3V Buck Converter Breakout - 3.3V Output 600mA Max

Your power supply problems just got SUPER SOLVED! This 3.3V Buck Converter Breakout board is great for supplying power to low voltage circuits from a single Li-Ion cell battery or USB power. This chip provides up to 600-mA load current across the entire input voltage range of 3.5 to 5.5V. Great for your portable project, we made this "pin compatible" with the LM1117-3.3V TO-220 chip so you can swap it in for better performance (90-95% efficiency!) There's also an ENable pin, tie it low to shut down the output completely.