Maxim’s DSM Smart Amplifier unleashes full potential of micro speakers

As devices continue to shrink and customers demand ever sleeker products, Maxim Integrated Products introduces the MAX98390 smart amplifier with integrated Dynamic Speaker Management (DSM) algorithm to efficiently deliver louder, clearer, richer sound at the lowest quiescent power in the market. The boosted, digital Class D DSM smart amplifier unleashes a system’s full audio potential by safely driving higher power levels (up to 5.1W) into tiny speakers typically rated for much lower power between 1 to 3W.

The miniaturization of consumer devices requires speakers to fit within smaller form factors, which has led to more applications moving towards the use of micro speakers. As speakers shrink, loudness or sound pressure level (SPL) decreases while the resonant frequency increases, leading to less bass. Driving the speakers harder to increase loudness and bass response can easily damage the micro speakers through overheating and over excursion. MAX98390 solves this challenge by utilizing integrated IV (current and voltage) sense and Maxim’s DSM algorithm to drive speakers to their maximum specified limits, while protecting against over excursion and over-temperature events. DSM’s thermal protection empowers designers to safely push their speakers well beyond their specified power rating enabling the speakers to produce their maximum loudness. DSM’s excursion protection enables designers to drive speakers to their specified excursion limits, producing sound up to two octaves below the resonant frequency limit.

To properly protect the speaker, amplifier algorithms must know the characteristics of the speaker, such as resonant frequency within its enclosure, excursion limit and voice coil thermal limit. Traditionally, designers had to go through the time-consuming and complex characterization process or rely on direct supplier support to characterize their speakers and enclosures. This challenge is further exacerbated as most projects start prototyping with multiple speakers per project, requiring several weeks of supplier support or requiring special equipment and expertise. The MAX98390 significantly reduces the design time through the easy-to-use DSM Sound Studio GUI that allows customers to quickly and easily characterize many speakers. Combined with DSM’s thermal protection, the result is maximum loudness across the significantly extended frequency ranges in minutes, with no complex programming required. To cater to the miniaturization of devices and shrinking batteries, the MAX98390 offers industry-leading peak efficiency at 86 percent, which is even further improved with DSM’s Perceptual Power Reduction (PPR) feature that can yield up to an additional 25 percent efficiency, and the lowest quiescent power consumption of ~24mW, making it the ideal choice for low power devices that need longer battery life.

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