Stereo 20W Class D Audio Amplifier – MAX9744 Adafruit

Pump up the volume with this 20W stereo amplifier! This slim little board has a class D amplifier onboard that can drive 2 channels of 4-8 ohm impedance speakers at 20W each. Power it with 5-12VDC using the onboard DC power jack and plug stereo line level into the 3.5mm stereo headphone jack and jam out with ease. Since it’s class D, its completely cool-running, no heat sinks are required and it’s extremely efficient – up to 93% efficiency makes it great for portable or battery powered rigs.

We like the MAX9744 amplifier at the heart of this board because its very easy to use, but it also has both analog and digital volume control capability. Use a single 1KΩ pot (we include one) to adjust volume analog-style. Or hook it up to your favorite microcontroller and send I2C commands to set 64-steps of volume amplification.

Some great stats about the MAX9744:

• Power from 4.5V-14V DC voltage
• Up to 93% efficient (88-93% typical)
• 20mA quiescent current (or put into shutdown for 1uA quiescent)
• Up to 29.5dB max gain
• Use DC or AC coupled line-level input, up to 3Vpp
• Filterless Spread-Spectrum Modulation Lowers
  Radiated RF Emissions from Speaker Cables
• 20W Stereo Output (4Ω, VDD = 12V, THD+N = 10%)
• Low 0.04% THD+N
• Integrated Click-and-Pop Suppression
• Short-Circuit and Thermal-Overload Protection

We took this lovely chip and wrapped it up into a breakout for you, with polarity-protection, jacks and terminal blocks, i2c level shifting, and a spot to solder in a volume pot.

Each order comes with one MAX9744 breakout board with all surface-mount parts fully assembled and tested. We also include 3 x 2pin and 1 x 3pin terminal blocks, a 470uF power filter capacitor and 1KΩ trim pot. To use this board, a little soldering is required to attach the terminal blocks and other components, but its fairly easy and expect it should take less than 15 minutes. Check out our detailed tutorial for assembly instructions and overall usage.

Note: The terminal blocks included with your product may be blue or black.

TECHNICAL DETAILS

Dimensions (without 0.1″ header or terminal blocks):

• Length: 54mm / 2.1″
• Width: 41mm / 1.6″
• Height: 2mm / .08″
• Weight: 11g

Datasheets, PCB files, Fritzing object and more in the tutorial!