Demand Peripherals     Robotics and Automation Made Easy

AAMP: Stereo 2 Watt Class-D Audio Amplifier

The Audio Amplifier Card (AAMP) uses the Diodes PAM8408 Class D amplifier to give up to 2 Watts of audio power.


- Stereo 2 Watt output
- Power efficiency over 85%
- Total Harmonic Distortion less than 0.2% (1 Watt, 8 ohms)
- 5 Volt input power using rugged screw terminals
- Optional FPGA connection for volume control
- 32 steps of volume control from -80dB to 24dB
- Computer controlled mute
- Industry standard 3.5mm input jack
- Diodes PAM8408



Class D amplifiers have a high frequency (relative to audio frequency) digital output. They use Pulse Density Modulation to make the average signal over a short span correspond to the audio output. The high frequency digital output is low pass filtered by the inductance of the speaker coil. A digital output is what gives Class D amplifiers such great efficiency and such low distortion.

Even if the average is low, the instantaneous output is at full power for brief periods. Underrated speakers can catch fire when driven to full power by a Class D amplifier. This is why you must use a 3 Watt (or higher) magnetic speakers with the AAMP card.

The schematic and layout of the AAMP are shown below. The Eagle schematic, board, and bill-of-materials are available here: aamp.sch, aamp.brd, and aamp.txt.




FPGA Defined Peripherals
User Interface
FPGA Configuration
FPGA Buttons & LEDs
Host Tx/Rx Interface
AVR Interface
Stereo Audio Amplifier
Text LCD and Keypad
Quad WS2812 Interface
Quad Slide Pot
IR Recv/Xmit
6 Digit LCD
RC Decoder
Keyfob RF Decoder
Rotary Encoder Interface
Quad Touch Interface
Motion Control
Dual DC Motor Controller
Dual Quadrature Decoder
Quad 13 Bit Servo
Bipolar Stepper Controller
Unipolar Stepper Controller
Simple Input / Output
Quad Binary Output
Quad Binary Input
Octal Input/Output
32 Channel Binary Output
32 Channel Binary Input
Quad Serial Output
Octal Serial Output
Octal 12-bit ADC
Quad Ping))) Interface
Pololu QTR Interface
Octal SRF04 Interface
Generic I2C
Generic SPI
Octal 8-Bit DAC
Quad Digital Potentiometer
Quad PWM Output
Quad PWM Input
Quad Event Counter
Real Time Clock
Dual Pulse Generator

Interface Cards
Control Cards
User Interface
Stereo Audio Amplifier
IR Recv/xmit
Six Digit LCD Display
Keyfob RF Receiver
Rotary Encoder
Quad Switch Card
Text LCD / keypad
Quad Slide Pot
Quad Touch Interface
Motion Control
Dual 7-amp H-bridge
Quad Open Drain Driver
Quad 10 Amp Relay Card
Input / Output
Octal 8-Bit DAC
Quad Digital Potentiometer
Octal 12-bit ADC
Octal SRF04
I2C Prototyping
SPI Prototyping
USB 2.0 Hub
Real Time Clock
Octal Input/Output
32 Channel Input
32 Channel Output
Power Distribution Card
15 Amp Power Distribution
5 Volt Switching Regulator
ATX Power Break-Out Card
Disk Drive Power Break-Out
MP43 Aluminum Mounting Plate
WW4 Large Prototyping Card
WW2 Prototyping Card
WW1 Small Prototyping Card
SMP SMD Prototyping Card