
Advantech SOM-Express Design Guide
70 Chapter 5 Carrier Board Design Guidelines
5.8 TV-Out
The TV-out display (TV DAC) interface consists of 3 outputs which can be used in
different combinations to support component video, S-video or composite video.
5.8.1 Signal Descriptions
Table 5.20 TV signals description
Pin Signal I/O Description
B97 TV_DAC_A O
TVDAC Channel A Output supports the following:
Composite video: CVBS
Component video: Chrominance (Pb) analog signal
S-Video: not used
B97 TV_DAC_B O
TVDAC Channel B Output supports the following:
Composite video: not used
Component video: Luminance (Y) analog signal
S-Video: Luminance analog signal
B97 TV_DAC_C O
TVDAC Channel C Output supports the following:
Composite video: not used
Component video: Chrominance (Pr) analog signal
S-Video: Chrominance analog signal
5.8.2 Design Guidelines
5.8.2.1 Termination resistor, output filter and ESD protection diodes
of TV DAC output
There are three DAC output pins: TV_DAC_A, TV_DAC_B, and TV_DAC_C.
One of the 150 # ± 1% parallel termination resistors is implemented on the SOM-
Express module. Please place another 150 # ± 1% parallel termination resistor, a set
of protection diodes (like BAT54S) and an output network filter on the carrier board.
The video output signals should overlay the ground plane and be separated by a
ground trace, inductors and ferrite beads in series.
Figure 5-35 shows the connection of TV-out.
SOM-Express
TV_DAC_A
TV_DAC_C
TV_DAC_B
Chipset
150ohm
150ohm
150ohm
Carrier board
Video
Filter
Video
Filter
Video
Filter
Connector
Figure 5-35 Connection of TV-out
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