ESP8266 Community Forum

- Wed Jun 08, 2016 2:16 pm #48802 Today I received my first self-made PCB's from dirty pcb's.

Previously I was using LM1117 voltage regulators to convert the 5v that my wall adapter supplies into 3.3v for the ES8266. To save room, I ordered SMD versions of the LM1117 thinking they would do exactly the same as the bigger through-hole versions. What I got was labeled "AMS1117-3.3V "

When I soldered everything in place, and powered it up, nothing happened. When I took measurements, I noticed that the power on the pins of the ESP was just 0.6v, so something was going wrong. Not much later, the AMS1117-3.3V started to smoke, so something was certainly wrong.

I also soldered one onto a board with no other components at all. It worked, but only gave me 2.9v as output. I measured all the lines on the PCB, there doesn't seem to be any problem there, so I'm suspecting that the AMS1117-3.3V is not the right choice. The datasheet doesn't give me much of a clue either, according to it, a input voltage of 4.8v should give me a output voltage of 3.3v, so with 5v I should be very close to that.

Does anybody have a clue what I'm doing wrong?
I've recently also ordered a few HT7333 LDO's, they have the same size, so possibly I could use them as a replacement....?

- Wed Jun 08, 2016 2:41 pm #48806 I don't know why you got one AMS1117 into smoke.
But one thing for sure, although I still have some in stock, the AMS1117 isn't a good LDO, especially when looking at quiescent current.
Yes, HT7333 is a better choice, there is also SPX3819 and XC6203.

- Wed Jun 08, 2016 4:01 pm #48811 I suspect you either got a particularly crappy batch of AMS1117 or somewhat more likely there's something wrong with your circuit. Does the pinout match or are there any shorts on your board?
You may want to consider posting your schematic & board files and high res photos of the actual board, perhaps someone here will spot an error...

- Wed Jun 08, 2016 6:48 pm #48816 check the pinouts!