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!
- 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
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.