When designing portable, battery-powered audio devices for consumer speaker applications, it is essential to maximize battery playback time and maintain excellent audio performance in a compact, low-system-cost form factor. Infineon Technologies' MERUS multilevel switching technology is designed to achieve low switching losses and highly efficient amplification at low and high output powers, bringing desired benefits in such applications.
The new ICs feature the second generation of this technology and come in a compact 40-pin QFN package. They primarily serve applications such as battery-powered speakers, Bluetooth/wireless/smart speakers and soundbars, conference speakers, and multi-channel/multi-room audio systems.
The new family consists of MA2304DNS with an integrated and fully configurable digital signal processor (DSP) and MA2304PNS with audio limiter and volume control capabilities. Both devices feature second generation multilevel switching Class D audio amplifiers with inductorless operation and provide a bridged load (BTL) – nominal output of 2 x 37 W and a power supply voltage range (PVDD) of 10 to 20V for high-fidelity audio performance.
Five-level voltage modulation delivers an ultra-low idle power of 52 mW without the need for complex dynamic rail tracking systems. This is at least five times smaller than traditional Class D audio amplifiers, making these devices ideal for battery-powered speaker applications with increased battery life and/or reduced battery cell cost.
At low power output, efficiency can be over 80%, offering longer battery life and easy thermal management in multi-channel products. Multilevel switching also relaxes electromagnetic compatibility (EMC) requirements and allows inductorless applications across the full power range at lower cost.
Compared to traditional two- and three-level Class D audio amplifiers, reduced electromagnetic interference (EMI) emissions enable rapid market launch without compromising audio performance or efficiency. In mains-powered multi-channel applications, reduced and scalable EMI enables industrial designs that would otherwise be impossible without the need for a heat sink or traditional LC filter.
An internal high-order feedback loop ensures low total harmonic distortion (THD) and low noise for excellent audio performance. Inductorless application contributes to lower output filtering, avoiding bulky inductors, thus reducing system cost without output power limitations.
The DSP built into the MA2304DNS is highly configurable and can correct imperfections and adjust real speaker applications (e.g. equalization, limiting and other similar functions). The MA2304PNS offers simpler volume control and limiter for systems where an application/connectivity processor does the audio processing.