The SSM2518 is a digital input, Class-D power amplifier that combinesa digital-to-analog converter (DAC) and a sigma-delta(Σ-Δ) Class-D modulator. This unique architecture enablesextremely low real-world power consumption from digitalaudio sources with excellent audio performance. The SSM2518is ideal for power sensitive applications, such as mobile phonesand portable media players, where system noise can corruptsmall analog signals such as those sent to an analog input audioamplifier.

Using the SSM2518, audio data can be transmitted to the amplifierover a standard digital audio serial interface, thereby significantlyreducing the effect of noise sources such as GSM interference orother digital signals on the transmitted audio. The closed-loopdigital input design retains the benefits of an all digital amplifier,yet enables very good PSRR and audio performance. The threelevel, Σ-Δ Class-D modulator is designed to provide the leastamount of EMI interference, the lowest quiescent power dissipation,and the highest audio efficiency without sacrificingaudio quality.

Input is provided via a serial audio interface, programmable toaccept all common audio formats including I²S and TDM. Controlof the IC is provided via an I²C control interface. The SSM2518can accept a variety of input MCLK frequencies and can useBCLK as the clock source in some configurations.

Additional features include a soft digital volume control, deemphasis,and a programmable digital dynamic rangecompressor.

The architecture of the SSM2518 provides a solution that offerslower power and higher performance than existing DAC plusClass-D solutions. Its digital interface also offers a better systemsolution for other products whose sole audio source is digital,such as wireless speakers, laptop PCs, portable digital televisions,and navigation systems.

Applications

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.