Maxim introduces the MAX9877, an audio subsystem. This device combines a mono Class D speaker amplifier; a DirectDrive, stereo headphone amplifier; and a bypass analog switch. In addition to this integration, the MAX9877 employs Maxim's third-generation, ultra-low-EMI, Class D amplifier technology to provide Class AB audio performance with Class D efficiency. It thus delivers 725mW of output power from a 3.7V supply into an 8Ω load with 85% (max) efficiency. Providing the industry's highest output power from a lithium-ion battery, the MAX9877 is ideal for cellular phones, portable media players (PMPs), and other applications that require high audio quality, output power, and efficiency. Maxim's patented, DirectDrive architecture produces a ground-referenced output from a single supply, thus eliminating the need for large DC-blocking capacitors.

To further save cost and space, the MAX9877 utilizes Maxim's active-emissions limiting and patented spread-spectrum modulation, which reduce EMI and eliminate the output filters typically required by Class D amplifiers. Additionally, the integrated, low-noise, analog DPST switch allows the Class D amplifier to be bypassed to reduce power consumption in portable devices, eliminating the need for an external switch. The MAX9877 also features input mixing, volume control, comprehensive click-and-pop suppression, and a flexible, user-defined input architecture with three preamplifier gain settings. All controls are enabled through an I²C interface. The MAX9877 is packaged in a 2.5mm x 2mm, 20-bump WLP that is fully specified over the -40°C to +85°C extended temperature range. Prices start at $1.62 (1000-up, FOB USA). An evaluation kit is available to speed designs.