
MAX4397DA/SA
Audio/Video Switch for Dual SCART Connectors
10
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Pin Description (continued)
PIN
MAX4397DA
MAX4397SA
NAME
FUNCTION
29
RF_CVBS_OUT
RF Modulator Composite Video Output. Internally biased at 1V.
30
TV_Y/CVBS_OUT
TV SCART Luma/Composite Video Output. Internally biased at 1V.
31
TV_R/C_OUT
TV SCART Red/Chroma Video Output. Internally biased at 1V for Red video
signal and 2.2V for Chroma video signal.
32
TV_G_OUT
TV SCART Green Video Output. Internally biased at 1V.
33
TV_B_OUT
TV SCART Blue Video Output. Internally biased at 1V.
34
VCR_Y/CVBS_OUT
VCR SCART Luma/Composite Video Output. Internally biased at 1V.
35
VCR_R/C_OUT
VCR SCART Red/Chroma Video Output. Internally biased at 1V for Red video
signals and 2.2V for Chroma video signal.
37
TV_R/C_IN
TV SCART Red/Chroma Video Input. Internally biased at 1.2V for Red video
signals, or 1.9V for Chroma video signals.
38
TV_Y/CVBS_IN
TV SCART Luma/Composite Video Input. Internally biased at 1.2V.
39
VCR_Y/CVBS_IN
VCR SCART Luma/Composite Video Input. Internally biased at 1.2V.
40
VCR_R/C_IN
VCR SCART Red/Chroma Video Input. Internally biased at 1.2V for Red video
signals and 1.9V for Chroma video signals.
41
VCR_G_IN
VCR SCART Green Video Input. Internally biased at 1.2V.
42
VCR_B_IN
VCR SCART Blue Video Input. Internally biased at 1.2V.
43
ENC_Y/CVBS_IN
Digital Encoder Luma/Composite Video Input. Internally biased at 1.2V.
44
ENC_R/C_IN
Digital Encoder Red/Chroma Video Input. Internally biased at 1.2V for Red
video signals, or 1.9V for Chroma video signals.
45
ENC_G_IN
Digital Encoder Green Video Input. Internally biased at 1.2V.
46
ENC_B_IN
Digital Encoder Blue Video Input. Internally biased at 1.2V.
47
ENC_Y_IN
Digital Encoder Luma Video Input. Internally biased at 1.2V.
48
ENC_C_IN
Digital Encoder Chroma Video Input. Internally biased at 1.9V.
EP
GNDAUD
Exposed Paddle. Solder to the circuit board ground (GNDAUD) for proper
thermal and electrical performance.
Detailed Description
The MAX4397DA/SA are switch matrices that route
audio and video signals between different ports using
the I2C interface. The ports consist of the MPEG
decoder output, and two SCART connectors for the TV
and VCR. Per EN50049 and IEC 933, the encoder can
only input a signal to the SCART connector, while TV
and VCR SCART connectors are bidirectional.
The MAX4397DA/SA circuitry consists of four major
sections: the video section, the audio section, the slow-
and fast-switching section, and the digital interface.
The video section consists of clamp and bias circuitry,
input buffers, reconstruction filters, a switch matrix, a Y/C
mixer, and output buffers. All video inputs are AC-cou-
pled through a 0.1F capacitor to set an acceptable DC
level using clamp or bias networks. The bidirectional
Red/Chroma outputs can be connected to ground using
I2C control to make them terminations when Red/Chroma
is an input (see the Video Inputs section).
The audio section features an input buffer, a switching
matrix, volume- or gain-control circuitry, and output dri-
vers. The audio inputs are AC-coupled through a 0.1F
capacitor. Only the audio encoder inputs of the
MAX4397DA are different from the MAX4397SA. The
MAX4397SA has a single-ended audio encoder input
while the audio encoder input for the MAX4397DA is dif-
ferential. The TV output audio path has volume control
from -56dB to +6dB in 2dB steps, while the VCR output
audio path has volume control from -6dB to +6dB in 6dB
steps. The MAX4397DA/SA can be configured to switch
inputs during a zero-crossing function to reduce clicks.