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) - 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. This board is a welcome upgrade to basic "LM386" amps!
The amplifier inputs go through 1.0uF capacitors, so they are fully 'differential' - if you don't have differential outputs, simply tie the R- and L- to the ground. The outputs are "Bridge Tied" - which means they connect directly to the outputs, with no connection to the ground. The output is a 360KHz square wave PWM that is then 'averaged out' by the speaker coil - the high frequencies are not heard. All the above means that you can't connect the output to another amplifier, it should drive the speakers directly.
Comes with a fully assembled and tested breakout board with 1.0uF input capacitors. We also include a header to plug it into a breadboard, pre-soldered 3.5mm screw-terminal blocks so you can easily attach/detach your speakers, a pre-soldered 2x4 header, and a jumper to change the amplifier gain on the fly. You will be ready to rock in 15 minutes! Speakers are not included; use any 3ohm or greater impedance speakers.
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
Five pin-selectable gains: 6 dB, 9 dB, 12 dB, 15 dB and 18 dB. 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
Revision History:
As of July 12, 2024- This board now comes with the terminal blocks and 2 x 4 header pre-soldered.
As of December 5, 2022– we've updated this PCB with Adafruit Pinguin to make a lovely and legible silkscreen - you may get the new PCB or the older version with vector fonts - both are identical other than the fancy silkscreen.
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