Audio; Only For Training And Service Purposes - LG KC780 Service Manual

3.13. Audio

KC780 Audio signal flow diagram as following diagram.
3.13.1. Audio amplifier sub system IC with Codec
The WM8990 is an ultra-low power hi-fi Codec designed for multimedia handsets. A powerful 1W speaker
driver can operate in class D or AB modes, providing total flexibility to the system designer. Low leakage,
high PSRR and pop/click suppression enable direct battery connection for the speaker supply. A flexible
input configuration supports two microphone inputs (single-ended or differential), a stereo line input, and a
mono differential line input. Four headphone drivers support fully differential headset drive, providing
excellent crosstalk performance and bass response, maximising stereo effects, and allowing the removal
of large and expensive headphone capacitors. The headphone outputs can also be configured to drive an
ear speaker. A fully differential path to these outputs direct from the input pins is available to maximise
signal quality and minimise power consumption. Stereo 24-bit sigma-delta ADCs&DACs provide hi-fi
quality audio playback, with a flexible digital audio interface supporting most commonly-used clocking
schemes. An integrated low power PLL provides additional flexibility.
Copyright © 2008 LG Electronics. Inc. All right reserved.

Only for training and service purposes

Figure 20 Audio signal flow diagram
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3. TECHNICAL BRIEF
LGE Internal Use Only