Adafruit MAX98357A I2S 3W Class D Amplifier Breakout Board

Introducing the Adafruit MAX98357A I2S 3W Class D Amplifier Breakout Board, an all-in-one solution for amplifying digital audio signals seamlessly compatible with the Raspberry Pi.

This breakout board simplifies the process of enhancing your digital sound files, offering an easy and cost-effective means to amplify your audio. By accepting standard I2S digital audio input, it not only decodes the signal into analog but also directly amplifies it to drive a speaker. Combining two breakouts (I2S DAC + Amp) into one compact unit, it streamlines the audio enhancement process.

Utilizing the I2S digital sound protocol—distinct from I2C—this board efficiently passes audio data on circuit boards. Typically managed by high-end chips and processors, I2S format facilitates audio input and output via three or four pins (data in, data out, bit clock, and left-right channel select). A built-in DAC chip converts I2S input to analog output, suitable for driving headphones.

Despite its small size, this mono amplifier delivers a surprising 3.2 Watts of power into a 4-ohm impedance speaker (5V power @ 10% THD). Featuring a class D controller, it operates within a wide voltage range of 2.7V-5.5VDC, ensuring versatility for various projects, including portable and battery-powered applications. Equipped with built-in thermal and over-current protection, it maintains operational safety and reliability.

The audio input adheres to the I2S standard, accommodating both 3.3V and 5V logic data. The “Bridge Tied” outputs connect directly to the speaker without grounding, producing a ~300KHz square wave PWM output that is then smoothed by the speaker coil. Consequently, direct connection to another amplifier is not recommended, as the output is intended for driving speakers directly.

The Gain pin enables gain adjustment, providing default gain of 9dB, with options for 3dB, 6dB, 9dB, 12dB, or 15dB gain settings through resistor manipulation. The ShutDown/Mode pin facilitates chip shutdown and selection of the I2S audio channel piped to the speaker. By default, the amp outputs a (L+R)/2 stereo mix into mono output, adjustable to left or right output with resistor configuration.

Compatible with Raspberry Pi, Arduino Zero, and other microcontrollers or microcomputers with I2S audio outputs, this amplifier breakout board offers versatile integration options for a wide range of projects.

Features:

1. Output Power: 3.2W at 4Ω, 10% THD, 1.8W at 8Ω, 10% THD, with 5V supply
2. PSRR: 77 dB typ @ 1KHz
3. I2S sample rates from 8kHz to 96kHz
4. No MCLK required
5. Click + Pop reduction
6. Five pin-selectable gains: 3dB, 6dB, 9dB, 12dB, 15dB
7. Excellent click-and-pop suppression
8. Thermal shutdown protection
9. Dimensions (L x W x H) mm: 19.4 x 17.8 x 3.0
10. Product Weight: 1.2g

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    Package Includes:

    1 x Adafruit MAX98357A I2S 3W Class D Amplifier Breakout Board