2x3W digital audio amplifier PAM8403

Product detailed description

The compact Class D stereo amplifier based on the PAM8403 circuit delivers up to 2 × 3 W to two speakers while operating on a standard 5V power supply. Thanks to its filterless design, it requires no output inductors or heatsink, and with board dimensions of 21 × 19 mm, it occupies minimal space. Ideal for portable speakers, projects with Arduino or ESP32, playing back voice prompts, or as a power stage for a Bluetooth receiver.

Specifications:

• Circuit: PAM8403 (Diodes Incorporated)
• Amplifier Class: D, filterless design
• Number of Channels: 2 (stereo)
• Power Supply: 2.5–5 V DC (absolute maximum 5.5 V), stable 5 V recommended
• Output power:
  • At 4 Ω: 2 × 3 W (5 V, THD 10 %)
  • At 8 Ω: 2 × 1.7 W (5 V, THD 10 %)
• Speaker Impedance: 4 Ω or 8 Ω
• Output Type: bridge-tied load (BTL), differential – none of the outputs must be connected to ground
• Gain: fixed 24 dB (the board has no volume control)
• THD+N Distortion: from 0.08 % (at low power)
• Efficiency: up to 90% (approx. 85–89% at 1.7 W / 8 Ω, approx. 80–83% at 3 W / 4 Ω)
• Quiescent current: approx. 10–15 mA
• PSRR: 45–55 dB at 1 kHz
• Protections:
  • Thermal: shutdown at 120 °C, hysteresis 40 °C
  • Short-circuit: on outputs
  • Under-voltage (UVLO): 2.0 V
• Pins (solder pads with 2.54 mm pitch):
  • Power supply: 5V (+) and (−)
  • Input: L, R and GND (ground symbol on board)
  • Output: L OUT (+ / −), R OUT (+ / −)
• Cooling: not required, circuit operates without a heatsink
• Dimensions: 21 × 19 mm
• Weight: 5 g
• Suitable speakers from our range:
  • Speaker 3W 4Ω 40mm
  • Speaker 5W 4Ω 40mm
  • Speaker 2W 8Ω 18x53x15mm Stereo
  • Speaker 5W 8Ω 100x45x21mm Stereo

Important wiring notice:

• Outputs are bridged (BTL). Connect each speaker separately between the + and − of the respective channel. Never connect the output to ground, to the power supply, or to the output of the second channel– otherwise the amplifier will only buzz and vibrate, or it may be destroyed. No resistor should be placed between the amplifier and the speaker.
• Connect the speaker directly, without a passive crossover. Filterless Class D assumes that the speaker itself is the load. A passive crossover is a non-standard load for this circuit – distortion increases sharply, and ringing and oscillations may occur. For a two-way system, insert an LC filter at the output or use an amplifier with a filtered output.
• Do not compromise on the power supply. At full power, the current draw exceeds 1 A; a weak USB port or a 5V pin of a development board will result in distortion, volume drop, or restarts. Use a stable power supply and connect a 100–470 µF blocking electrolytic capacitor as close as possible to the power pins.
• The board does not handle volume control. The gain is fixed at 24 dB; therefore, adjust the level at the signal source or insert a dual potentiometer of approx. 10 kΩ before the input.
• The input is designed for line level. A preamplifier is required for a microphone or a phono cartridge.

Package contents:

• 1× PAM8403 Digital Audio Amplifier 2× 3 W

Note:

• This product is not a standalone functional unit and may require professional installation.
• Product images are for illustrative purposes only and may sometimes differ from the actual appearance of the item. However, this does not change their basic properties.