Description Of Circuits - Zenith D52WLCD Series Service Manual

1. Main Part
1.1 CXA2069Q :
Audio/Video Switch
(1) Description
The CXA2069Q is a 7-input, 3-output audio/video switch fea-
turing I 2 C bus compatibility for TVs. This IC has input pins
that are compatible with S2 protocol.
(2) Features
• 4 inputs that are compatible with S2 protocol
• Serial control with I 2 C bus
• 7 inputs, 3 outputs
• The desired inputs can be selected independently for each
of the 3 outputs
• Wide band video amplifier (20 MHz, –3 dB)
• Y/C MIX circuit
• Slave address can be changed (90H/92H)
• Audio muting from external pin
• High impedance maintained by I 2 C bus lines (SDA, SCL)
even when power is OFF
• Wide audio dynamic range (3 Vrms typ.)
(3) Description of Operation
The CXA2069Q is a TV I 2 C bus-compatible AV switch IC.
The video system and the stereo audio system
both have 7 inputs and 3 outputs each. 4 of the 7 video sys-
tem inputs support S2 and S protocols.
The desired inputs can be independently assigned to each
output (in the audio system, the left and right
channels are processed as one unit) by I 2 C bus control.
However, the same input is assigned to both the
video and audio system output 3.

DESCRIPTION OF CIRCUITS

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