Adafruit
Stereo 20W Class D Audio Amplifier - MAX9744
A compact Class D stereo amplifier breakout based on the Maxim MAX9744. It drives two channels of 4–8 Ω speakers at up to 20 W each, powered from 4.5–14 V DC...
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A compact Class D stereo amplifier breakout based on the Maxim MAX9744. It drives two channels of 4–8 Ω speakers at up to 20 W each, powered from 4.5–14 V DC. With up to 93% efficiency, it runs cool without heatsinks — ideal for portable and battery-powered audio projects.
Volume can be controlled via an included 1 kΩ trim pot (analogue) or via I²C commands from a microcontroller with 64 steps of digital volume adjustment. The board includes polarity protection, audio jacks, terminal blocks, and I²C level shifting.
Key Features
- 20 W Stereo Output – 4 Ω speakers, 12 V supply, THD+N = 10%
- Class D Efficiency – 88–93% typical, no heatsink required
- Power Supply – 4.5 V to 14 V DC via onboard barrel jack
- Audio Input – 3.5 mm stereo headphone jack, up to 3 Vpp (DC or AC coupled)
- Dual Volume Control – Analogue (1 kΩ pot included) or I²C digital (64 steps)
- Max Gain – 29.5 dB
- Low Distortion – 0.04% THD+N
- Low Power – 20 mA quiescent, 1 µA in shutdown mode
- Protection – Short-circuit, thermal overload, and click-and-pop suppression
- Spread-Spectrum Modulation – Reduces radiated RF emissions from speaker cables
Package Contents
- 1× MAX9744 amplifier breakout (SMD components pre-assembled)
- 3× 2-pin terminal blocks
- 1× 3-pin terminal block
- 1× 470 µF power filter capacitor
- 1× 1 kΩ trim pot
Resources
Jargon buster
Plain-language definitions for the technical terms used above.
- breakout
- 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
- 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.
- microcontroller
- 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.
- RF
- RF means radio frequency, referring to signals used for wireless communication and other high-frequency electronics. A low-noise, stable power supply is important for RF circuits because power noise can affect signal quality and measurements.
- SMD
- SMD means surface-mount device, a component style designed to be soldered directly onto the surface of a circuit board rather than through holes. SMD parts are compact and mounted flat on the board, which suits smaller and mass-produced designs.
- Terminal block
- 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.
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adafruit 20w stereo audio amplifier class d max9744
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