2 x 1.5W, Stereo Class D Audio Subsystem with DirectDrive Headphone Amplifier

The MAX9775/MAX9776 combine a high-efficiency Class D, stereo/mono audio power amplifier with a mono DirectDrive® receiver amplifier and a stereo DirectDrive headphone amplifier.

Maxim's 3rd-generation, ultra-low-EMI, Class D audio power amplifiers provide Class AB performance with Class D efficiency. The MAX9775/MAX9776 deliver 1.5W per channel into a 4Ω load from a 5V supply and offer efficiencies up to 79%. Active emissions limiting circuitry and spread-spectrum modulation greatly reduce EMI, eliminating the need for output filtering found in traditional Class D devices.

The MAX9775/MAX9776 utilize a fully differential architecture, a full-bridged output, and comprehensive click-and-pop suppression. A 3D stereo enhancement function allows the MAX9775 to widen the stereo sound field immersing the listener in a cleaner, richer sound experience than typically found in portable applications. The devices utilize a flexible, user-defined mixer architecture that includes an input mixer, volume control, and output mixer. All control is done through I²C.

The mono receiver amplifier and stereo headphone amplifier use Maxim's DirectDrive architecture that produces a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors, saving cost, space, and component height.

The MAX9775 is available in a 36-bump WLP (3mm x 3mm) package. The MAX9776 is available in a 32-pin TQFN (5mm x 5mm) or a 36-bump WLP (3mm x 3mm) package. Both devices are specified over the extended -40°C to +85°C temperature range.

Applications

* Cell Phones—Mid and High Tier * Handheld Gaming Consoles * Portable Multimedia Players

* Unique Spread-Spectrum Modulation and Active Emissions Limiting Significantly Reduces EMI

* 3D Stereo Enhancement (MAX9775 Only)

* Up to 3 Stereo Inputs

* 1.5W Stereo Speaker Output (4Ω, VDD = 5V)

* 50mW Mono Receiver/Stereo Headphone Outputs (32Ω, VDD = 3.3V)

* High PSRR (68dB at 217Hz)

* 79% Efficiency (VDD = 3.3V, RL = 8Ω, POUT = 470mW)

* I²C Control—Input Configuration, Volume Control, Output Mode

* Click-and-Pop Suppression

* Low Total Harmonic Distortion (0.03% at 1kHz)

* Current-Limit and Thermal Protection

* Available in Space-Saving, 36-Bump WLP (3mm x 3mm) and 32-Pin TQFN (5mm x 5mm) Packages