750mW Audio Amplifiers with Headphone Amp, Microphone Preamp, and Input Mux

All versions are No Longer Available.

The MAX9765/MAX9766/MAX9767 family combines speaker, headphone, and microphone amplifiers, all in a small thin QFN package. The MAX9765 is targeted at stereo speaker playback applications and includes a stereo bridge-tied load (BTL) speaker amp, stereo headphone amp, single-ended output mic amp, input MUX, and I²C control. The MAX9766 is targeted at mono speaker playback applications and includes a mono BTL speaker amp, stereo headphone amp, differential output mic amp, input MUX, and I²C control. The MAX9767 is targeted at applications that do not require a headphone amp and includes a stereo BTL speaker amp, differential output mic amp, and parallel control.

These devices operate from a single 2.7V to 5.5V supply. A high 95dB PSRR allows these devices to operate from noisy supplies without additional power conditioning. An ultra-low 0.003% THD+N ensures clean, low distortion amplification of the audio signal. Click-and-pop suppression eliminates audible transients on power and shutdown cycles.

In speaker mode, the amplifiers can deliver up to 750mW of continuous average power into a 4Ω load. In headphone mode, the amplifier can deliver up to 65mW of continuous average power into a 16Ω load. The gain of the amplifiers is externally set, allowing maximum flexibility in optimizing output levels for a given load. The MAX9765/MAX9766 also feature a 2:1 input multiplexer, allowing multiple audio sources to be selected. The various functions are controlled by either an I²C-compatible (MAX9765/MAX9766) or simple parallel control interface (MAX9767).

All devices include two low-noise microphone preamps, a differential amp for internal microphones, and a single-ended amplifier for additional external microphones. A microphone bias output is provided, reducing external component count.

The MAX9765/MAX9766/MAX9767 are available in a thermally efficient 32-pin thin QFN package (5mm x 5mm x 0.8mm). All devices have short-circuit and thermal-overload protection (OVP) and are specified over the extended -40°C to +85°C temperature range.

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