Every time I connect a new ESP8266 (ESP-12F) to a new LD1117v33, as long as I insert an ammeter in between, it runs fine. It consumes about 70mA during normal running, and almost 0mA when in deep sleep. Once I remove the ammeter from the circuit, the ESP is immediately damaged, so that it begins heating up, and after about a minute is too hot to touch. When I connect the ammeter back again, the ESP constantly draws either 320mA or 550mA, irrespective whether it's in "normal" operation or in deep sleep. This obviously means something inside breaks, but what exactly and why?
I'm not using any capacitors on the input or output of the LD1117v33. I know most people complain that it's necessary for "stability," but I don't see how it would be relevant to this particular problem. The voltage shown on the DMM is always 3.2V, which seems fine. I really need to get to the bottom of this, otherwise I'm going to keep damaging ESP after ESP. They all continue to work, but permanently draw way too much current and run hot, and it always only happens once I remove the ammeter out of the circuit or abstain from inserting it to begin with.
When I power the ESP from a 300W/20A down converter (ebay,) it runs perfect & cool, even if the voltage is 3.4V, 3.5V, or 3.1V. If I use a tiny down-converter (also EBay; don't know exact model) instead to power small electronics such as the ESP, that converter also gets too hot to touch. Although I never thought to check, I'm beginning to realize the same problem might be happening there, too. I never realized any of this before because I assumed it was normal for the heatsink the LDO is attached to to get that hot, and I never cared about power consumption or measured it. I probably have been damaging all of my ESPs up to this point without realizing it. It just now came to light since I started using deep sleep and measuring current consumption for a battery powered project. As for the mini-down converter, I simply assumed it was too weak to handle the ESP, whereas most likely the ESP was also drawing far too much current than it normally would.
My theory: The sudden current inrush upon connecting is throwing the LDO off, exposing the ESP momentarily to the full 12V input to the LDO. The inrush current might be damaging internal capacitors under the hood, but aren't they supposed to withstand high current swings by design/purpose? I don't see why any voltage spikes would accomodate the current inrush, since there is no reason to assume there is any inductance beyond usual parasitic levels. If that were actually the reason, why/how would adding capacitors to the LDO stabilize/resolve the issue?
Meanwhile I'll test further by adding a 1 ohm resistor in series to VDD, to dampen that inrush. I'll respond with results once they're in.