Hey all I am having an issue using this AMS1117-3.3 SMD:

According to its documents it says its either a fixed or adjustable version? So I hook it up as I see in the documents:

The left pin (1) being Ground.
The middle pin (2) being the 3.3vdc output.
The right pin (3) being the 5vdc input.

Once I hook all those up, I test it with my voltmeter on 20 and i get a reading of 0.09vdc????????

I've already tried 3 of these to make sure I didnt blow it or anything but it keeps saying that readout.

Am I missing something here? This must be the adjustable version since I can not just hook it up and expect 3.3vdc to come out?

I also tried to just step down from 5vdc to 3.3vdc using 100ohm resistor but that only produced around 4vdc output....

Here is the way I hooked it up:

The document I am reading is HERE

And also on my breadboard:

And what I have it connected to (ESP8266 ESP-12f) this is its document stating above 80mA average:

 

Did you notice the tab is also connected to output?

Post a picture of you build and indicate what is what.

 

The datasheet says a 22uF solid tantalum capacitor is required on the output and that the minimum output current is 10mA so you need a resistor of not more than 330Ω across the output.

I don't think the lack of either of these would reduce the output so drastically but they have to be eliminated to be sure.

Does the regulator get warm?

 

The assembly looks OK. The breadboard is sketchy, unless you extended the leads they are not making good contact.

With an output of 0.9 volts I would look for shorts. If all your devices do this then you have a bad batch.

(I just got a batch of these off Amazon, I hope they are good LOL)

 

i dont have any capacitor on hand so is there any combine resistors I could you to get what i need for the input? Does the fixed version need anything on the output?

 

i dont have any capacitor on hand so is there any combine resistors I could you to get what i need for the input?

For the input to what?

Does the fixed version need anything on the output?

It needs a minimum load of 10mA.

Disconnect the output on your proto board and tack on a 10mA load. That would eliminate something you're trying to power as the problem.

Also check to make sure that none of the pads on your proto board are causing shorts to the tab of the regulator.

Why are there no markings visible on the regulator? If they came off while you were soldering, that's a sign of counterfeits. Did the parts come from China?

 

Can I not use some resistor's to drop the 5vdc down to 3.3vdc?

 

Can I not use some resistor's to drop the 5vdc down to 3.3vdc?

You don't want to do that.

The voltage drop of a series resistor would depend on current. A varying current would give a varying voltage.

A resistive divider would waste a lot of power because divider current needs to be at least 10 times the load current for proper stiffness.

A zener regulator would have similar power waste.

Fix the problem with the regulator.

 

Does the regulator get warm?

 

Alright this is what I have to work with:

2 x .1uF 100v Stack Metal Film
2 x 1N4148TA 100v 0.2A
2 x 35v 470uF
2 x 25v 47uF 20%
2 x 35v 220uF
2 x 10v 100uF 20%
2 x 1.0uF 50v 20%

Any of these work to step it down or use for the capacitors on the AMS1117?

 

Any of the 47 to 470 uF caps should work, but I'd be shocked if your regulator is putting out 0.09 volts because of too little load capacitance or especially too little load period.

Try turning the power off and see what an ohmmeter things the resistance is across that 3.3 volt output. My guess is there is a pretty good short right there.

 

Alright does this look like a good one to go by?

 

If there is something drawing too much current then this will pull the output voltage down. It won't damage the regulator but it will get warm hence my question about whether the regulator gets warm which you haven't answered.

 

FORGET THE DRAWING, check the resistance from the Ground pin to the Output pin on your regulator with the power turned off. Then see what is pulling it down.

 

im just going to design a pcb and get it populated with the needed componets.

Appreciate all the help!

 

I would never spin a PCB until I got my breadboard working.

 

Sure looks like the tab is connected (touching the pads) to column "I" on your circuit board..
Thus the output would be shorted to ground..