40W Class-D Audio Amplifier with Digital Master Volume Control

The OPA1688 device used in this design belongs to the SoundPlus family of Texas Instruments. It is a low-noise operational amplifier designed for audio applications. It can either operate using a single voltage supply or a split voltage supply. The MAX5486, which is also used in this project, is a dual 40kΩ digital logarithmic potentiometer that has a debounced pushbutton interface ideal to control the volume and balance the left and right channel of this project. It has 32 log-spaced tap points with a buffered wiper. The power amplifier in this design is the TPA3106D1, which is a 40W class-D audio power amplifier with 92% efficiency that eliminates the need for an external heat sink. Read more

6W Inductor Free Stereo BTL Class D Audio Amplifier Circuit Diagram

The circuit is a class-D 6W inductor free audio amplifier for BTL (bridged-Tied Load) stereo speaker at up to 6Ω to 8Ω per channel. The TPA3144D2 has an advance EMI suppression technology with spread spectrum control and 1SPW modulation scheme that enables the use of inexpensive ferrite bead filters at the outputs. The design is applicable in inductor free application with limited distance length of wire between the amplifier and speakers. Read more