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The MAX98357 I2S 3W Class-D Audio Amplifier Module is an all-in-one digital audio output solution designed for modern microcontrollers. Utilizing the MAX98357A IC in a compact WLP/BGA-style silicon layout, this breakout board eliminates the noisy analog audio path entirely by receiving raw PCM digital audio signals over a 3-wire I2S bus ($BCLK$, $LRCK$, $DIN$).

The onboard circuitry takes digital audio directly from platforms like ESP32, Raspberry Pi, or STM32, converts it internally via its high-resolution DAC, and amplifies it through an efficient filterless Class-D driver stage. It delivers up to $3.2\text{W}$ into a $4\Omega$ speaker at $10\%$ THD ($2.5\text{W}$ at $1\%$ THD) from a $5\text{V}$ power rail. Supplied without pre-soldered pin headers, this board allows developers to solder custom right-angle pins, straight headers, or direct silicone lead wires to match tight enclosure footprints and custom 3D-printed audio gadgets.

Key Features and Benefits

• Direct I2S Digital Interface: Accepts digital PCM audio signals over 3 lines ($BCLK$, $LRCK$, $DIN$), bypassing noise-susceptible analog audio inputs.

• Filterless 3.2W Class-D Output: Drives up to $3.2\text{W}$ output into $4\Omega$ or $1.6\text{W}$ into $8\Omega$ speakers with over $92\%$ power efficiency.

• No MCLK (Master Clock) Required: Uses internal PLL clock recovery from the $BCLK$ signal, reducing the required GPIO connection count on host microcontrollers.

• Configurable Gain Settings: Selectable gain levels ($3\text{dB},6\text{dB},9\text{dB},12\text{dB},15\text{dB}$) via a single $GAIN$ pin configuration.

• Selectable Audio Channel (L/R/Mix): Configurable $SD\_MODE$ pin allows selection of Left channel, Right channel, or Mono-mix $(L+R)/2$ output for multi-speaker setups.

• Unsoldered Terminal Flex: Supplied with loose header pins and terminal block, giving total mounting freedom for low-profile projects.

Technical Specifications

Pinout & Wiring Guide

Breakout Interface Connections:

• $LRCK$ (WS): Left/Right Frame Clock / Word Select Line

• $BCLK$ (SCK): Bit Clock Line (Bit rate sync)

• $DIN$ (SD): Serial Data Input Line

• $GAIN$: Gain select setting (GND $=12\text{dB}$, VDD​=9dB, Unconnected $=12\text{dB}$ with internal pull-up)

• $SD\_MODE$: Shutdown and channel select input ($GND=$ Shutdown, VDD​= Right Channel, Unconnected $=(L+R)/2$ Mono mix)

• $GND$: System Ground ($0\text{V}$)

• $Vin$ (VDD​): Power Supply ($2.5\text{V}-5.5\text{V DC}$)

• $+$ / $-$ Speaker Out: Bridge-Tied Load (BTL) speaker output terminals ($4\Omega -8\Omega$ impedance)

AUDIO WIRING WARNING: The speaker output is a differential Bridge-Tied Load (BTL) driver. Do NOT connect the positive ($+$) or negative ($-$) speaker terminals to common system ground ($GND$). Doing so will damage the internal output stage transistors.

Applications

• ESP32 Internet Radio & Smart Speakers: Streaming web radio, Spotify streams, or custom voice assistants (e.g., ESP-ADF / Alexa voice nodes).

• Retro Gaming Handhelds: High-quality digital sound reproduction for Raspberry Pi Zero/Pico handheld consoles.

• Text-to-Speech & Sound Effect Boxes: Playing MP3/WAV voice notifications and alert sound clips in IoT devices.

• Portable Bluetooth/Wi-Fi Speakers: Battery-powered compact speakers using $18650$ lithium-ion power cells.

Package Includes

• 1 x MAX98357 I2S 3W Class-D Audio Amplifier Breakout Board

• 1 x 7-Pin Male Header Strip (Unsoldered)

• 1 x 2-Pin Screw Terminal Block for Speaker Output (Unsoldered)

Shipping & Delivery

• Free shipping on orders above ₹999 across India

• Dispatched within 1-3 business days

• Expected delivery: 3-7 business days depending on location

• Secure packaging to ensure safe transit of electronic components