During development of Arduino USB Host Shield I designed small and simple boost converter to provide 5V to Vbus from 3.3V input. The circuit, built around Linear Technology’s LTC3426, worked so well, that I decided to release a standalone version. There are many uses for such converter – LCD contrast bias being most typical. Another example when 3.3V to 5V converter could be handy, is old style Arduino shields. This photo shows my converter sitting on empty space of 3.3V-only Arduino Pro board.
Maximum output current of the converter is 650ma. It can be loaded up to 700, but inductor becomes warm. Output ripple is around 25mv at 500ma. If less ripple is desired, 3.3uH inductor can be used. Output capacitor can be increased also, hovever, benefits are marginal. Measured efficiency of this circuit is around 90%.
Project files, including Eagle schematic and layout files, as well as Gerbers, are available from Downloads section. Design rules are pretty relaxed and board is routed almost on a single side (the other side is a ground plane), so making one at home should not be a problem. Also, PCBs and assembled and tested converters are available in the store.
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