The DSM Class D digital smart amplifier amplifies the full audio potential of a system by safely driving higher power levels (up to 5.1W) to much lower-powered small speakers between 1 and 3 watts.
The miniaturization of consumer devices requires speakers to fit into smaller form factors, leading to a shift towards micro speakers in more applications. As speakers shrink, the loudness level, or sound pressure level (SPL), decreases as the resonant frequency increases, resulting in less bass. Driving speakers harder to increase loudness and bass response can easily damage micro speakers through overheating and overexcitation. The MAX98390 addresses this challenge by utilizing Maxim's built-in IV (current and voltage) sense and DSM algorithm to push speakers to their specified maximum limits while protecting against overexcitation and overtemperature events. DSM's thermal protection allows designers to safely drive their speakers beyond their specified power rating, enabling them to produce their maximum volume. DSM's excitation protection allows designers to control loudspeakers to their specified excitation limits, producing sound up to two octaves below the resonant frequency limit.
To protect the loudspeaker, the amplifier's algorithms must be aware of the loudspeaker's characteristics, such as the resonant frequency within its enclosure, the excitation limit, and the voice coil's thermal limit. The MAX98390 reduces design time through DSM Sound Studio's graphical user interface, allowing customers to quickly and easily characterize a wide range of loudspeakers. Combined with DSM's thermal protection, the result is maximum loudness across all extended frequency ranges in minutes, without the need for complex programming. Addressing device miniaturization and battery shrinkage, the MAX98390 offers peak efficiency of 86 percent, further enhanced by DSM's Perceptual Power Reduction (PPR) feature, which can provide an additional 25 percent efficiency. With a low standby power consumption of approximately 24 mW, it is ideal for low-power devices requiring extended battery life.
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