Hi Forum Users,
I'm working with the LM1117IMPX-5.0/NOPB a linear voltage regulator used to drop up to 15 volts down to 5. I'm trying to use this to give safe power to my ATMega328p-pu. I hook up the regulator like the circuit below. This circuit was found in the data sheet for the LM1117. I then supply a 12 volt 2 amp power supply.
Typically nothing! I get a variation of readings. Some start at 5 volts but then quickly drop to 0.2. Others sit at 0.2ish volts.
I've tried setups with two tantalums, one tantalum (only on output), and zero tantalum capacitors.
I've tried multiple units and have only gotten the correct 5 volt output twice. I just tried using a 0.1 uf ceramic capacitor to limit noise on the output but still no luck.
I purchased the units at Arrow.com.
The data sheet can be found here: http://www.ti.com/lit/ds/symlink/lm1117.pdf
Please help. Thanks!
What package are you using? I see the datasheet circuit, but how's about a picture of YOUR circuit? What are you using to solder it?
Thanks for the comment! I just fixed it. My lack of motivation to solder meant I was trying to use a breadboard this whole time. I was sticking the three surface mount pins into the breadboard slots. I thought they were making contact due to the voltage readings. Turns out, besides the one time on breadboard when contact was being made, the voltage was due to the discharging capacitors. That's why the voltage was slowly dropping.
Essentially my circuit was open the whole time so it wouldn't work. I spent a lot of time researching and trying different things. From too much noise to faulty capacitors and 1117 units. It's always the dumb mistakes that bite me in the butt.
I just threw the circuit onto perf board due to your comment and POOF! It works!! Thank you.