Introduction: The LM380N Audio Amp

I was a little intimidated by this IC the first time I looked at the datasheet because of all the ground connections. I thought it was a little silly. But after prototyping with this audio amp I don't think I'll ever go back to the LM386.

Step 1: Materials

1 LM380N
1 10 ohm resistor
1 potentiometer between 1k and 10k, this is your volume knob so its really your choice.
2 470uF electrolytic capacitors
Jumper wires
1 3.5mm audio aux jack
A power source, I'm using a 12.5 regulated power supply, you can go as low as 10 volts and as high as 22 volts. 8 AA batteries would run it nicely if you're looking to make it portable.

Step 2: The Circuit

First let's get all of those ground connections out of the way. Connect pins 3, 4, 5, 6, 7, 10, 11, and 12 to ground.

Then connect your positive power source to pin 14 through a 10 ohm resistor. And connect pin 14 to ground through a 470uF capacitor. The negative lead should be connected to the negative rail.

Now connect your common input of the 3.5mm jack to ground and the right and left both to the left pin of the potentiometer. The middle pin should be connected to pin 2 of the lm380 and the right pin should be connected to ground.

Now put a 470uF capactor from pin 8 to the positive terminal of your speaker (Negative lead of capacitor connects to the speaker) and the negative speaker wire should be grounded.

Step 3: The Schematic

This is not my schematic but this may be a little easier to follow.

Step 4: Conclusion

Try this circuit if you haven't before. I think you'll be pleasantly surprised. There's no feedback or crackling of any kind like I always get with the LM386. I will definitely be using these in more of my projects. I also ordered some more parts from digikey today so I may have more audio amps to come :) happy prototyping!

Comments

author
grayl (author)2017-01-22

Remember R1 has to carry the total load of the circuit, including losses. With a 4 ohm speaker, nominally you have 6.2 ohms across the input voltage. Given 18.6 volts, that's 3 amps. The 1/4 watt resistor you show will not cut it.

author
mastergabe (author)2015-12-28

Hi

I am using this as an amplifier for my car and i was wondering how i could use the one chip to amplify both the left and right terminals on the headphone jack

author
Soldat7 (author)2014-05-10

I love the LM380. the 386 is nice for a beginner with a budget, but very quickly people may find themselves with a speaker of 2w for which the 380 is far better and if you ever need more power to drive a bigger speaker you can just replace it by the LM384. which is basically the LM380 pin by pin, but with 5w rating.

My number 1 favorite power-amp however is the the TDA2003 10watt amp. doesn't require a lot of components (just a couple of caps and resistors which help quality a LOT) and can push out very good sound even at a lowly 12v. Only downside is that needs a decent heatsink to work at full efficiency. If you never tried it i would suggest to take a look if you ever need something heavier.

author
francisdsa (author)2014-01-06

a circuit diagram would be appreciated

author
dbyrd26 (author)francisdsa2014-01-06

I have now included the schematic

author
dbyrd26 (author)2014-01-06

I'll give that one a try. I ordered a few low watt and a few higher watt amps yesterday. I think amps are my favorite circuits right now. I'm thinking about etching a board for this circuit today since we're snowed in up here :)

author
tutdude98 (author)2014-01-06

try tda2822m its in every pc speaker amp and also it can give 2x5w if you "overclock it"