This incredibly small stereo amplifier is surprisingly powerful - able to deliver 2 x 3.7W channels into 3 ohm impedance speakers. 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 (over 90% efficient when driving an 8Ω speaker at over a Watt).

This amplifier is perfect for portable and battery-powered projects. It has built in thermal and over-current protection, but you really have to drive it hard before it even gets warm! This board is a welcome upgrade to basic "LM386" amps!

Specifications:

• Output Power: 3.7W at 3Ω, 10% THD, 1.7W at 8Ω, 10% THD, with 5V Supply
• Passes EMI limit unfiltered with up to 12 inches (30 cm) of speaker cable
• High 83dB PSRR at 217Hz
• Spread-Spectrum Modulation and Active Emissions Limiting
• Differential Inputs
• Five pin-selectable gains: 6dB, 9dB, 12dB, 15dB and 18dB. Select with a jumper or by setting the G and G' breakout pins (see schematic for breakout board showing gain pin settings for details)
• Excellent click-and-pop suppression
• Thermal and short-circuit/over-current protection
• Low current draw: 2mA quiescent and 10uA in shutdown mode

What is a Class D Amplifier?

A Class D Amplifier uses PWM to generate high-frequency square waves with a duty-cycle proportional to the voltage level of the input audio signal. By minimizing the transition time between fully on and fully off, the MOSFET drivers are able to operate at a very high efficiency. Class D amplifiers such as this one typically operate at over 90% efficiency, compared to efficiencies of 50% or less for typical class AB amplifiers.

The high frequency square-wave component of the output signal is filtered by the inductance of the speaker voice coil, leaving only the amplified audio signal.

Available from Adafruit!