User Manual

Page 69
ICE Module
4.10 TV-Out
The TV-Out display interface of the COM Express Module consists of three individual
digital-to-analog converter (DAC) channels, which can be used in different
combinations to support S-Video (Y/C), Composite Video or Component Video
(YPbPr). The corresponding signals can be found on the COM Express module
connector row B.
4.10.1 Signal Description
Table 4-19: TV-Out Signal Descriptions
Pin Signal I/O Description
B97 TV_DAC_A O Analog TVDAC Channel A Output supports the following:
Composite video: CVBS
Component video: Chrominance (Pb) analog signal
S-Video: not used
B98 TV_DAC_B O Analog TVDAC Channel B Output supports the following:
Composite video: not used
Component video: Luminance (Y) analog signal.
S-Video: Luminance analog signal.
B99 TV_DAC_C O Analog TVDAC Channel C Output supports the following:
Composite video: not used
Component: Chrominance (Pr) analog signal.
S-Video: Chrominance analog signal.
4.10.2 TV-Out Routing Guideline
4.10.2.1 Signal Termination
Each of the TV-DAC channels should have a 150 Ω ±1% pull-down termination
resistor connected from the TV-DAC output of the COM Express module to the carrier
board ground. This termination resistor should be placed as close as possible to the
TV-Out connector on the carrier board. A second 150 Ω ±1% termination resistor
exists on the COM Express module itself.
4.10.2.2 Video Filter
There should be a PI-filter placed on each TV-DAC channel output to reduce
high-frequency noise and EMI. The PI-filter consists of two 10pF capacitors with a
120Ω @ 30Mhz ferrite bead between them. It is recommended to place the PI-filters
and the termination resistors as close as possible to the TV-Out connector on the
carrier board. The PI-filters should be separated from each other by at least 50mils or
more in order to minimize crosstalk between the TV-DAC channels.