โมดูลขยายเสียงสำหรับ ESP32 MAX98357 I2S 3W Class D Amplifier Breakout

โมดูลขยายเสียงสำหรับ ESP32 MAX98357 I2S 3W Class D Amplifier Breakout



Product description


This is an all in one digital audio amp breakout board that works incredibly well with the Raspberry Pi! If youre looking for an easy and low cost way to get you digital sound files bumpin then the MAX98357 I2S Amplifier Breakout is for you. It takes standard I2S digital audio input and not only decodes it into analog but also amplifies it directly into a speaker. Perfect for adding compact amplified sound it takes 2 breakouts (I2S DAC + Amp) and combines them into one.

I2S (not to be confused with I2C) in a digital sound protocol that is used on circuit boards to pass audio data around. Many high end chips and processors manage all of the audio in digital I2S format. Then to input or output data three or four pins are used (data in data out bit clock and left-right channel select). Usually for audio devices theres a DAC chip that will take I2S in and convert it to analog that can drive a headphone.

This small mono amplifier is surprisingly powerful - able to deliver 3.2 Watts of power into a 4 ohm impedance speaker (5V power @ 10% THD). Inside the miniature chip is a class D controller able to run from 2.7V-5.5VDC. Since the amp is a class D its incredibly efficient - making it perfect for portable and battery-powered projects. It has built in thermal and over-current protection but we could barely tell it got hot.

The audio input is I2S standard you can use 3.3V or 5V logic data. The outputs are Bridge Tied - that means they connect directly to the outputs no connection to ground. The output is a ~300KHz square wave PWM that is then averaged out by the speaker coil - the high frequencies are not heard. All the above means that you cant connect the output into another amplifier it should drive the speakers directly.

Theres a Gain pin that can be manipulated to change the gain. By default the amp will give you 9dB of gain. By connecting a pullup or pull down resistor or wiring directly the Gain pin can be set up to give 3dB 6dB 9dB 12dB or 15dB.

The ShutDown/Mode pin can be used to put the chip in shutdown or set up which I2S audio channel is piped to the speaker. By default the amp will output (L+R)/2 stereo mix into mono out. By adding a resistor you can change it to be just left or just right output

Works great with Raspberry Pi Arduino Zero and any other microcontroller or microcomputer with I2S audio outputs

Specification

Output Power: 3.2W at 4 10% THD 1.8W at 8 10% THD with 5V supply
PSRR: 77 dB typ @ 1KHz
I2S sample rates from 8kHz to 96kHz
No MCLK required
Click + Pop reduction
Five pin-selectable gains: 3dB 6dB 9dB 12dB 15dB
Excellent click-and-pop suppression
Thermal shutdown protection