# Adafruit STEMMA Audio Amp
## Overview
The ** Adafruit STEMMA Audio Amp** is a super small mono amplifier is surprisingly powerful - able to deliver up to 2.5 Watts into 4-8 ohm impedance speakers. Inside the miniature chip is a class D controller, able to run from 2.0V-5.5VDC. Since the amp is a class D, it's very efficient (over 90% efficient when driving an 8Ω speaker at over half a Watt) - making it perfect for portable and battery-powered projects. It has built in thermal and over-current protection but we could barely tell it got hot. There's even a volume trim pot so you can adjust the volume on the board down from the default 24dB gain. This board is a welcome upgrade to basic "LM386" amps!
This board is a simplified version of our breadboard-friendly Adafruit Mono 2.5W Class D Audio Amplifier board. This version is designed to be 'plug and play' - with no soldering required. You can input the audio via the JST-PH 3 Pin connector - such as a [pin header cable](https://www.adafruit.com/product/3893) or [one with alligator clips](https://www.adafruit.com/product/4030). The trade-off is that this board doesn't have differential inputs, instead the audio inputs are referenced to the power/signal ground wire.
The input to the amplifier goes through 1.0uF capacitors so you can have DC. The output is "Bridge Tied" - that means the output pins connect directly to the speaker pins, no connection to ground. The output is a high frequency 250KHz square wave PWM that is then 'averaged out' by the speaker coil - the high frequencies are not heard. All the above means that you can't connect the output into another amplifier, it should drive the speakers directly.
The board comes fully assembled and tested. We also include header to plug it into a breadboard and a 3.5mm screw-terminal blocks so you can easily attach/detach your speaker. You will be ready to rock in 15 minutes! **Speaker is not included, use any 4 ohm or greater impedance speaker.**
- Output Power: 2.5W at 4Ω, 10% THD, 1.5W at 8Ω, 10% THD, with 5.5V Supply
- 50dB PSRR at 1KHz
- Filterless design, with ferrite bead + capacitors on output.
- Fixed 24dB gain, onboard trim potentiometer for adjusting input volume.
- Thermal and short-circuit/over-current protection.
- Low current draw: 4mA quiescent and 0.5mA in shutdown (due to pullup resistor on SD pin)
**Note:** The terminal block included with your product may be blue or black.
- [Next Page](https://learn.adafruit.com/stemma-audio-amp/pinouts.md)
## Primary Products
### Adafruit STEMMA Audio Amp - Mono 2.5W Class D - PAM8302
[Adafruit STEMMA Audio Amp - Mono 2.5W Class D - PAM8302](https://www.adafruit.com/product/5647)
The ** Adafruit STEMMA Audio Amp** is a super small mono amplifier is surprisingly powerful - able to deliver up to 2.5 Watts into 4-8 ohm impedance speakers. Inside the miniature chip is a class D controller, able to run from 2.0V-5.5VDC. Since the amp is a class D, its...
In Stock
[Buy Now](https://www.adafruit.com/product/5647)
[Related Guides to the Product](https://learn.adafruit.com/products/5647/guides)
## Featured Products
### STEMMA JST PH 2mm 3-Pin to Male Header Cable - 200mm
[STEMMA JST PH 2mm 3-Pin to Male Header Cable - 200mm](https://www.adafruit.com/product/3893)
This cable will let you turn a JST PH 3-pin cable port into 3 individual wires with high-quality 0.1" male header plugs on the end. We're carrying these to match up with our Hallowing, for extending and connecting sensors or LEDs - and the wires are even color coded!
In Stock
[Buy Now](https://www.adafruit.com/product/3893)
[Related Guides to the Product](https://learn.adafruit.com/products/3893/guides)
### JST PH 2mm 3-pin Plug to Color Coded Alligator Clips Cable
[JST PH 2mm 3-pin Plug to Color Coded Alligator Clips Cable](https://www.adafruit.com/product/4030)
This cable will let you turn a JST PH 3-pin cable port into 3 individual wires with grippy mini alligator clips. We're carrying these to match up with any of our boards or breakouts with 3-pin 'STEMMA' connectors on them such as the
In Stock
[Buy Now](https://www.adafruit.com/product/4030)
[Related Guides to the Product](https://learn.adafruit.com/products/4030/guides)
### STEMMA JST PH 2mm 3-Pin to Female Socket Cable - 200mm
[STEMMA JST PH 2mm 3-Pin to Female Socket Cable - 200mm](https://www.adafruit.com/product/3894)
This cable will let you turn a JST PH 3-pin cable port into 3 individual wires with high-quality 0.1" female header sockets on the end. We're carrying these to match up with our Hallowing, for extending and connecting sensors or LEDs - and the wires are even color coded!
In Stock
[Buy Now](https://www.adafruit.com/product/3894)
[Related Guides to the Product](https://learn.adafruit.com/products/3894/guides)
### JST PH 2mm 3-pin Plug-Plug Cable - 100mm long
[JST PH 2mm 3-pin Plug-Plug Cable - 100mm long](https://www.adafruit.com/product/4336)
This cable is a little over 100mm / 4" long and fitted with JST-PH 3-pin connectors on either end.
We dig the solid and compact nature of these connectors and the latch that keeps the cable from coming apart easily. We're carrying these to
In Stock
[Buy Now](https://www.adafruit.com/product/4336)
[Related Guides to the Product](https://learn.adafruit.com/products/4336/guides)
### Mono Enclosed Speaker with Plain Wires - 3W 4 Ohm
[Mono Enclosed Speaker with Plain Wires - 3W 4 Ohm](https://www.adafruit.com/product/4445)
Listen up! This single 2.8" x 1.2" speaker is the perfect addition to any audio project where you need 4 ohm impedance and 3W or less of power. We particularly like these speakers as they are small and enclosed for good audio volume and quality. This speaker _does..._
In Stock
[Buy Now](https://www.adafruit.com/product/4445)
[Related Guides to the Product](https://learn.adafruit.com/products/4445/guides)
### Speaker - 40mm Diameter - 4 Ohm 5 Watt
[Speaker - 40mm Diameter - 4 Ohm 5 Watt](https://www.adafruit.com/product/3968)
Hear the good news! This speaker is a great addition to any audio project where you need a 4 Ohm impedance and 3W or less of power.
At **40mm diameter** it has a more square-ish shape, but a smaller face. Sound quality and volume are nicely sandwiched between our...
In Stock
[Buy Now](https://www.adafruit.com/product/3968)
[Related Guides to the Product](https://learn.adafruit.com/products/3968/guides)
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