The MAX9777/MAX9778 combine a stereo 3W bridge-tied load (BTL) audio power amplifier, stereo single-ended (SE) headphone amplifier, headphone sensing, and a 2:1 input multiplexer all in a tiny 28-pin thin QFN package. These devices operate from a single 4.5V to 5.5V supply and feature an industry-leading 100dB PSRR, allowing these devices to operate from noisy supplies without the addition of a linear regulator. An ultra-low 0.002% THD+N ensures clean, low-distortion amplification of the audio signal. Patented click-and-pop suppression minimizes audible transients on power and shutdown cycles. Power-saving features include low 4mV VOS (minimizes DC current drain through the speakers), low 13mA supply current, and a 10µA shutdown mode. A MUTE function allows the outputs to be quickly enabled or disabled.
A headphone sense input detects the presence of a headphone jack and automatically configures the amplifiers for either speaker or headphone mode. In
speaker mode, the amplifiers can deliver up to 3W of continuous average power into a 3Ω load. In headphone mode, the amplifier can deliver up to 200mW 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 amplifiers also feature a 2:1 input multiplexer, allowing multiple audio sources to be selected. The multiplexer can also be used to compensate for limitations in the frequency response of the loud speakers by selecting an external equalizer network. The various functions are controlled by either an I²C-compatible (MAX9777) or simple parallel control interface (MAX9778).
The MAX9777/MAX9778 are available in a thermally efficient 28-pin thin QFN package (5mm x 5mm x 0.8mm). These devices have thermal-overload protection
(OVP) and are specified over the extended -40°C to +85°C temperature range.
Key Features
Applications/Uses
Industry-Leading, Ultra-High 100dB PSRR
3W BTL Stereo Speaker Amplifier
200mW Stereo Headphone Amplifier
Low 0.002% THD+N
Patented Click-and-Pop Suppression
ESD-Protected Outputs
Low Quiescent Current: 13mA
Low-Power Shutdown Mode: 10µA
MUTE Function
Headphone Sense Input
Stereo 2:1 Input Multiplexer
Optional 2-Wire, I²C-Compatible or Parallel
Interface
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