Only For Training And Service Purposes - LG GM750 Service Manual

3.13.2.2 MAX9877 audio interface
The MAX9877 combines a high-efficiency Class D audio power amplifier with a
stereo Class AB capacitorless DirectDrive™ headphone amplifier. Maxim's 3rd
generation, filterless Class D amplifier with active emissions limiting technology
provides Class AB performance with Class D efficiency. The MAX9877 delivers up
to 725mW from a 3.7V supply into an 8Ω load with 87% efficiency to extend battery
life. The filterless modulation scheme combined with active emissions limiting
circuitry and spread-spectrum modulation greatly reduces EMI while eliminating the
need for output filtering used in traditional Class D devices.
The stereo Class AB headphone amplifier in the MAX9877 uses Maxim's patented
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 device utilizes a user-defined input architecture,
three preamplifier gain settings, an input mixer, volume control, comprehensive
click-and-pop suppression, and I2C control. A bypass mode feature disables the
integrated Class D amplifier and utilizes an internal DPST switch to allow an
external amplifier to drive the speaker that is connected at the outputs of the
MAX9877. The MAX9877 is available in a thermally efficient,
space-saving 20-bump WLP package.
Copyright © 2009 LG Electronics. Inc. All right reserved.

Only for training and service purposes

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3. Technical Brief
LGE Internal Use Only