CXA2161R Datasheet, PDF (31/43 Pages) Sony Corporation – I2C Bus Compatible Audio Video (AV) Switch & Electronic Volume Control

CXA2161R
Y/C Mixer
A Y/C mixer can be used for mixing Luminance and Chrominance signals for use with an external RF modulator
connected to VOUT_7. The Y/C mixer is controlled via the I²C data bus. The signal may be a mix of the TV Y/C
signals or simply the TV CVBS signal. It is also possible to select the CVBS signal from the digital encoder.
The circuit is shown in Fig 14. with a trap circuit used to give 6dB attenuation at 4.43MHz of the Luminance
signal. The output VOUT_7 cannot drive loads higher than 20kΩ resistive. If it is necessary to drive a 75Ω
load with this output then an external emitter follower arrangement should be used.
R/C
0, 1, 2
or 3dB
6dB
VOUT_3
CVBS/Y
VIN_8 = CVBS
6dB
VOUT_4
Mixer
2kΩ
switch
6dB
VOUT_7
TRAP
R
For recommended values:
C
see application circuit
L
Fig. 14. Internal Y/C Mixer Circuit
Switching the Video Outputs Off
Each video output can be individually turned off using the I²C. When turned off, the output is set to a high
impedance state and hence the current consumption and power dissipation is reduced. After power on, all the
video outputs are set to the high impedance state.
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