LG -P350 Service Manual page 54

3. TECHNICAL BRIEF
3.13.2.2 TPA2055D3 audio interface
The.TPA2055D3 is an audio subsystem with a mono class-D power amplifier, a stereo class-G DirectPath
TM
headphone amplifier, and bypass switches. Class-G improves MP3 playback time while DirectPath eliminates
the need for external dc-blocking output capacitors. The headphone amplifier drives up to 35mW into 16-
ohm speakers form a 1.8-V supply.
The subsystem includes two stereo single-ended(SE) inputs. The stereo inputs are also configurable as
differential mono inputs. Each input channel has an independent volume control. Inputs can be individually
selected or mixed together. Input impedances remain constant over all input and output gains.
Operating mod and volume levels are controlled over an I C interface. The i C interface is compatible over a
2 2
1.5V to 5.5V digital supply range.
The TPA2055D3 uses SpeakerGuard TM Limiter technology to prevent output clipping distortion and
excessive power to the speakers and headphones. The speaker and headphone amplifier outputs have
independent limiter levels, allowing optimum loudness and protection for each output.
The TPM2055D3 is available in a 0.5 mm pitch 20-bump WCSP with less than 0.8 mm height.
Figure. Detailed diagram of TPA2055D3 audio interface
LGE Internal Use Only - 54 - Copyright © 011 LG Electronics. Inc. All right reserved.
Only for training and service purposes