The SSM2518 is a digital input, Class-D power amplifier that combines a digital-to-analog converter (DAC) and a sigma-delta (Σ-Δ) Class-D modulator. This unique architecture enables extremely low real-world power consumption from digital audio sources with excellent audio performance. The SSM2518 is ideal for power sensitive applications, such as mobile phones and portable media players, where system noise can corrupt small analog signals such as those sent to an analog input audio amplifier.
Using the SSM2518, audio data can be transmitted to the amplifier over a standard digital audio serial interface, thereby significantly reducing the effect of noise sources such as GSM interference or other digital signals on the transmitted audio. The closed-loop digital input design retains the benefits of an all digital amplifier, yet enables very good PSRR and audio performance. The three level, Σ-Δ Class-D modulator is designed to provide the least amount of EMI interference, the lowest quiescent power dissipation, and the highest audio efficiency without sacrificing audio quality.
Input is provided via a serial audio interface, programmable to accept all common audio formats including I2S and TDM. Control of the IC is provided via an I2C control interface. The SSM2518 can accept a variety of input MCLK frequencies and can use BCLK as the clock source in some configurations.
Additional features include a soft digital volume control, de-emphasis, and a programmable digital dynamic range compressor.
The architecture of the SSM2518 provides a solution that offers lower power and higher performance than existing DAC plus Class-D solutions. Its digital interface also offers a better system solution for other products whose sole audio source is digital, such as wireless speakers, laptop PCs, portable digital televisions, and navigation systems.
**APPLICATIONS**
Mobile phones
Portable media players
Laptop PCs
Wireless speakers
Portable gaming
Small LCD televisions
Navigation systems
### Features and Benefits
Filterless, digital input Class-D amplifier
Serial digital audio interface supports common formats I2S, left justified, right justified, TDM1-16, and PCM
2 channels × 2 W into 4 Ω and 2 channels × 1.4 W into 8 Ω with 1% THD+N, when using a 5 V supply
I2C control interface or standalone operation
91% efficiency at full scale into an 8 Ω load
97 dB signal-to-noise ratio (SNR), A-weighted
80 dB power supply rejection ratio (PSRR) at 217 Hz
