I have (a chinese clone of) a Wemos D1 mini board, which uses the ESP8266 microprocessor. Since the ESP8266 has a 3.3V operating voltage, it includes a low dropout regulator for the USB 5V. According to the Wemos D1 mini schematic, it uses the RT9013 LDO .
According to the (RT9013 schematic), it has an operating voltage of 2.2V to 5.5V. This I do not understand, I thought the LDO could only drop to a lower voltage?
Also, it has a dropout of 250mV at 500mA, which I thought meant that there must be at least 3.55V. With that in mind, what's the best amount of AAA batteries I can use in series to power it?
I assume non-rechargeable batteries have an operating voltage of around 1.5V, which would mean that I would need three AAA batteries (4.5V). I've also read that the lowest the battery gets is 1.2V or so, which would mean that the total voltage would only be 3.6 V. This is still above the 3.55V minimum, so should it be OK?