Pulse Density Modulation Digital-Input Class D Audio Amplifier For Portable Applications

The SSM2517 Class D audio amplifier combines a filterless mono Class D amplifier with an audio DAC in a tiny 1.5 mm x 1.5 mm package - the same size as some existing analogue-input Class D amplifiers. The PDM interface on the SSM2517 is the same digital interface supported by digital microphones in many handset and laptop applications. A digital interface helps to lower overall system cost, eases board layout considerations, and allows more freedom in industrial design for placement of loudspeaker transducers. Because audio is transmitted digitally to the SSM2517, the effect of GSM interference or other sources of electrically coupled noise are minimised. The small package and filterless design means that the SSM2517 requires very little board space, enabling compact designs in portable products. The integrated DAC and sigma-delta modulator architecture minimises system design challenges by mitigating EMI (electromagnetic interference). The closed-loop modulator design enables very good rejection of power supply ripple and excellent audio performance. The SSM2517 is 90 percent power efficient, making it ideal for power sensitive applications.