I2S DAC with 3W amplifier - MAX98357A (OT6745)

If you're looking for an easy and affordable way to amplify your digital audio files, the MAX98357 I2S Amp Breakout is for you. It takes standard I2S digital audio input and not only decodes it to analog, but also amplifies it directly to a speaker. Perfect for adding compact amplified sound, it combines 2 breakouts (I2S DAC + Amp) into one.
What is I2S?
I2S is a digital audio protocol used in circuit boards to pass audio data. Many advanced chips and processors manage all audio in digital I2S format. To input or output data, three or four pins are used (data in, data out, bit clock, and left-right channel select). Typically for audio devices there is a DAC chip that takes I2S and converts it to analog that can drive headphones.
This little mono amplifier is surprisingly powerful - it can deliver 3.2 watts of power into a 4 ohm speaker (at 5V supply and 10% THD). Inside the miniature chip is a class D controller, which operates from a 2.7V-5.5VDC supply voltage. Because the amplifier is class D, it is extremely efficient, making it perfect for portable and battery powered projects. It has built-in thermal and overcurrent protection, but we barely noticed it getting warm.
The audio input is I2S standard, you can use either 3.3V or 5V logic data. The outputs are "bridge tied" - that means they connect directly to the outputs, with no connection to ground. The output is a ~300KHz squarewave PWM which is then 'averaged' by the speaker coil - the high frequencies are not heard. All of the above means you cannot connect the output to another amplifier, it must drive the speakers directly.
There is a Gain pin that can be adjusted to change the gain. By default the amp will give you 9dB of gain. By connecting a pull-up or pull-down resistor, or wiring directly, the Gain pin can be set to 3dB, 6dB, 9dB, 12dB or 15dB.
The ShutDown/Mode pin can be used to put the chip to sleep, or set which I2S audio channel is routed to the speaker. By default the amp will output a (L+R)/2 stereo mix to mono output. By adding a resistor you can change it to left only or right only out.

Specifications:

Output Power: 3.2W at 4Ω, 10% THD, 1.8W at 8Ω, 10% THD, at 5V supply
PSRR: 77 dB typ. at 1 kHz
I2S sample rates from 8 kHz to 96 kHz
No MCLK required
Click + Pop reduction
Five pin-selectable gains: 3 dB, 6 dB, 9 dB, 12 dB, 15 dB
Thermal shutdown protection
Comes with 7 header pins and 2 screw terminals
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