The Adafruit Mono 2.5W Class D Audio Amplifier delivers powerful sound from a tiny package. Based on the PAM8302 chip, it drives 4–8 ohm speakers at up to 2.5 W with over 90% efficiency — making it ideal for portable and battery-powered audio projects. A significant upgrade over basic LM386-based amplifiers.
The amplifier runs from 2.0–5.5 V DC and includes built-in thermal and over-current protection. An on-board trim pot lets you adjust volume down from the default 24 dB gain. The differential inputs pass through 1.0 µF coupling capacitors, and the bridge-tied output connects directly to the speaker — no connection to ground required.
Key Features
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2.5 W Output – Into 4 Ω at 10% THD; 1.5 W into 8 Ω (at 5.5 V supply)
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Class D Efficiency – Over 90% efficient at 8 Ω, half-watt load
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Wide Supply Range – 2.0–5.5 V DC, perfect for battery power
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Volume Trim Pot – Adjustable from the fixed 24 dB gain
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Differential Inputs – AC-coupled via 1.0 µF capacitors; tie A− to ground for single-ended sources
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Bridge-Tied Output – Drives speakers directly; not designed to feed another amplifier
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Built-In Protection – Thermal shutdown and short-circuit/over-current protection
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Low Power Draw – 4 mA quiescent, 1 µA in shutdown mode
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Filterless Design – Ferrite bead + capacitors on output; 50 dB PSRR at 1 kHz
Ideal For
- Portable and battery-powered audio projects
- Adding sound output to microcontroller projects
- Alarm and notification systems
- Interactive exhibits and installations
Package Contents
- 1× Adafruit PAM8302 Mono Class D Amplifier Breakout (assembled and tested)
- 1× Header strip
- 1× 3.5 mm screw terminal block (colour may vary)
Note: Speaker not included. Use any speaker with 4 Ω or greater
impedance. The bridge-tied output should drive speakers directly — do not connect the output to another amplifier.
Jargon buster
Plain-language definitions for the technical terms used above.
- breakout
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A breakout board carries a small or fine-pitched component and brings its connections out to standard, breadboard- and header-friendly pins. Describing a part as a breakout means it can be wired into a project without soldering directly to the component's tiny contacts.
- DC
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DC means direct current, where electricity flows in one constant direction, as supplied by batteries, USB ports and many plug-pack power supplies. When a product specifies DC, it runs from a DC supply rather than mains AC, so you need to provide the correct voltage and polarity.
- Impedance
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Impedance is the total opposition a component or circuit presents to alternating current, measured in ohms, combining resistance with frequency-dependent reactance. It appears in many contexts, such as matching a speaker's impedance (for example 4 ohm or 8 ohm) to an amplifier or the input and output impedance of signal circuits, and a correct match helps avoid weak signals, distortion or damage.
- microcontroller
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A microcontroller is a small computer on a single chip that runs a stored program and controls connected inputs and outputs such as buttons, sensors, displays and communication interfaces. In a device built around one, it is the part that executes the code and coordinates the device's behaviour.
- Terminal block
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A terminal block is a connector that joins wires together in a neat, removable, or serviceable way, usually clamping each wire under a screw or spring instead of soldering. It makes it easier to connect, change, or service wiring without permanent joints.