TDA3MV Datasheet, PDF (246/256 Pages) Texas Instruments – TDA3x SoC for Advanced Driver Assistance Systems (ADAS) 15mm Package (ABF) Silicon Revision 2.0

TDA3MV, TDA3MA
TDA3LX, TDA3LA
SPRS964C – JUNE 2016 – REVISED JULY 2017
www.ti.com
8.10 CVIDEO/SD-DAC Guidelines and Electrical Data/Timing
The device's analog video CVIDEO/SD-DAC TV analog composite output can be operate in one of two
modes: Normal mode and TVOUT Bypass mode. In Normal mode, the device’s internal video amplifier is
used. In TVOUT Bypass mode, the internal video amplifier is bypassed and an external amplifier is
required.
Figure 8-72 shows a typical circuit that permits connecting the analog video output from the device to
standard 75-Ω impedance video systems in Normal mode.
cvideo_tvout
R_OUT
Reconstruction
Filter^(A)
~9.5 MHz
C_AC^(B)
cvideo_vfb
A. Reconstruction Filter (optional)
B. AC coupling capacitor (optional)
Figure 8-72. TV Output (Normal Mode)
Figure 8-73 shows a typical circuit that permits connecting the analog video output from the device to
standard 75-Ω impedance video systems in TVOUT Bypass mode.
cvideo_vfb
R_LOAD
Reconstruction
Filter^(A)
~9.5 MHz
Amplifier
3.7 V/V
75 W
C_AC^(B)
A. Reconstruction Filter (optional). Note: An amplifier with an integrated reconstruction filter can alternatively be used
instead of a discrete reconstruction filter.
B. AC coupling capacitor (optional)
Figure 8-73. TV Output (TVOUT Bypass Mode)
During board design, the onboard traces and parasitics must be matched for the channel. The video DAC
output pins (cvideo_tvout / cvideo_vfb) are very high-frequency analog signals and must be routed with
extreme care. As a result, the paths of these signals must be as short as possible, and as isolated as
possible from other interfering signals. In TVOUT Bypass mode, the load resistor and amplifier/buffer
should be placed as close as possible to the cvideo_vfb pin. Other layout guidelines include:
• Take special care to bypass the vdda_dac power supply pin with a capacitor.
• In TVOUT Bypass mode, place the R_LOAD resistor as close as possible to the Reconstruction Filter
and Amplifier. In addition, place the 75-Ω resistor as close as possible (< 0.5 inch) to the
Amplifier/buffer output pin. To maintain a high-quality video signal, the onboard traces after the 75-Ω
resistor should have a characteristic impedance of 75 Ω (± 20%).
• In Normal mode,cvideo_vfb is the most sensitive pin in the TV out system. The R_OUT resistor should
be placed as close as possible to the device pins. To maintain a high-quality video signal, the onboard
traces leading to the cvideo_tvout pin should have a characteristic impedance of 75 Ω (± 20%) starting
from the closest possible place to the device pin output.
• Minimize input trace lengths to the device to reduce parasitic capacitance.
• Include solid ground return paths.
• Match trace lengths as close as possible within a video format group.
246 Applications, Implementation, and Layout
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