I'm planning a hobby project with the following characteristics
- 3.3 V circuit, battery operated (by regulating standard AAA batteries)
- Most of the time in "sleep" mode, so I need a very small quiescent current
- When operating it will consume 100-350 mA
- Linear regulator to avoid noise and ripples
I've chosen the MCP1825 linear LDO regulator because it has enough power (500 mA), very low dropout voltage (less than 210 mV) and reasonable quiescent current (less than 120 µA).
My questions are:
- What if I don't put any reverse current protection? Will the PMOS pass element in MCP1825 provide some protection?
- Could I avoid adding reverse current protection if I'm careful with batteries' polarity?
- If I have to put some sort of reverse current protection, how would you advice designing a simple one with very low (or non-existing) dropout voltage and quiescent current?