MAX98357A I2S Class D Mono Audio Amplifier Module

The MAX98357A is a compact, easy-to-use digital audio amplifier module that accepts I2S digital audio input and directly drives a speaker, eliminating the need for a separate DAC and amplifier stage. Based on the Maxim MAX98357A Class D amplifier IC, it combines an I2S digital-to-analog converter with a high-efficiency Class D power stage, making it ideal for ESP32, Raspberry Pi, and Arduino audio projects.

Key Features

• Digital I2S audio input – no external DAC required
• Built-in Class D mono audio amplifier
• Output power up to 3.2W into a 4-ohm speaker
• High efficiency of up to 92 percent
• No MCLK signal required for operation
• Five selectable gain levels: 3dB, 6dB, 9dB, 12dB, 15dB
• Supports Left, Right, or (Left/2 + Right/2) channel output
• Built-in click and pop noise suppression
• Short-circuit and thermal shutdown protection
• Easy integration with ESP32, Raspberry Pi, and Arduino

Technical Specifications

Applications

• IoT and Smart Speaker Projects
• ESP32 and Raspberry Pi Audio Output
• Voice Assistant Devices
• Portable and Battery-Powered Audio Systems
• Robotics Sound Notification Systems
• DIY Bluetooth and Wireless Speakers
• Embedded Audio Playback Systems
• Gaming and Haptic Feedback Devices

Important Notes

• Requires a digital audio source with I2S output (LRC, BCLK, DIN); does not accept analog audio input.
• Output is Bridge-Tied Load (BTL); connect the speaker directly and do not connect outputs to ground or another amplifier.
• Pull the SD pin low to place the module in shutdown mode.
• Select gain using the GAIN pin with pull-up or pull-down resistors as per the datasheet.
• Use a speaker with matching impedance (4 ohm or 8 ohm) for correct power delivery.
• Ensure adequate power supply capacity, especially at higher gain settings and output power.