Stereo Power Amplifier
The Digilent PmodAMP3 features an Analog Devices® SSM2518 2 watt Class-D Audio Power Amplifier. The module enables the use of I2S audio protocol or TDM to produce stereo audio at various sampling frequencies. Users may configure the digital volume and dynamic range control via an I2C interface. Additionally, the PmodAMP3 may be used in a stand-alone mode that does not require the use of the I2C interface.
Functional Description
The PmodAMP3 utilizes Analog Devices SSM2518 to reproduce digitally fed audio signals in separate left and right headphone jacks. The separation of the jacks enables better audio signal isolation.
Interfacing with the Pmod
The Pmod AMP3 communicates with the host board via the I2C protocol. Users may operate the Pmod AMP3 in either an I2C programmable mode or a simple stand-alone mode. The stand-alone mode is the default setting and can be activated by removing the shorting block on jumper JP5. When the stand-alone mode is active, jumpers JP3, JP4, and JP6 allow a simple hardware configuration of the amplifier.
Within the stand-alone mode jumper JP3 configuration determines whether to use Standard or Left Justified I2S protocol. Jumper JP4 determines if the MCLK input is 256 or 384 times the audio sampling frequency Fs. The jumper JP6 configures the amplifier to output at either 0dB or +12dB gain.
If JP5 is loaded, I2C is enabled so that the on-board chip can be configured. Consequently, the shorting blocks on both JP3 and JP4 must be removed so that the SCL and SDA lines are pulled to a logic high voltage state. JP6 sets the I2C address of the Pmod; both addresses are valid, but a user may want to use one particular address if another I2C device on the bus is using the other address.
Physical Dimensions
The pins on the pin header are spaced 100 mil apart. The PCB is 1.5 inches long on the sides parallel to the pins on the pin header and 0.8 inches long on the sides perpendicular to the pin header.