THS7374 Datasheet, PDF (24/37 Pages) Texas Instruments – 4-Channel SDTV Video Amplifier with 6th-Order Filters and 6-dB Gain

THS7374
SLOS590 – JULY 2008....................................................................................................................................................................................................... www.ti.com
Low-Cost SCART System
The THS7374 is an ideal device for use in low-cost
SCART systems. SCART is used primarily throughout
Europe and requires four video channels to support
the RGB and timing channel. The timing channel is
also utilized for CVBS signals for systems that do not
have separate RGB video signals. The connector
also adds audio and several other functions.
Figure 42 shows a low-cost application that allows for
a commonly-used SCART switching interface with a
simple CD4053 switch. The relatively high impedance
of this switch is acceptable in this configuration,
because the input impedance of the THS7374 is 800
kΩ and the audio signal impedance requirement is
less than 1 kΩ. Obviously, other switches and
methods could be used, but this alternative is very
low cost compared to fairly expensive SCART
switching ICs. It does not support all possible modes
and configurations, but it is a good fit to meet many
system requirements.
R'
G'
B'
CVBS/Sync
Left
Right
SOC
PCM17xx
VCR CVBS/
Sync Out
75 W
330 mF⁽¹⁾
+
THS7374
1 CH1 IN CH1 OUT 14
2 CH2 IN CH2 OUT 13
R
3 CH3 IN CH3 OUT 12
4 CH4 IN CH4 OUT 11
5 GND
V_S+ 10
R1
6 DISABLE BYPASS 9
7 NC
NC 8
TV CVBS/
Sync Out
75 W
330 mF⁽¹⁾
+
TV R' Out
75 W
330 mF⁽¹⁾
+
TV G' Out
75 W
330 mF⁽¹⁾
+
TV B' Out
75 W
330 mF⁽¹⁾
+
R1
To GPIO Controller
or GND
+3 V to +5 V
R1
Audio Left Out
470 W
47 mF
+12 V
Audio Right Out
470 W
47 mF
Amp
LPF Bias
R2
Amp
LPF Bias
R2
NE5532
DRV600
DRV601
A INH
B VEE
C VSS
CD4053
Audio Left Out
470 W
47 mF
Audio Right Out
470 W
47 mF
47 mF _{100 W}
100 kW
+V_BIAS
100 kW
47 mF 100 W
TV SCART
19 20 NC
17 18
15 16
13 14
75 W
Fast Blank
RGB/CVBS
(From GPIO)
11 12 NC
10 kW
+12 V
9
10 NC
470 W
7
8
5
6 NC
3
4
1
2 NC
1.5 kW
1.5 kW
STBY/TV
1 kW (From GPIO)
1 kW
16:9/4:3
(From GPIO)
21
VCR SCART
19 20 ^{VCR CVBS In}
17 18
0.1 mF
75 W
NC 15 16 NC
13 14
NC 11 12 NC
9
NC 7
10 NC
8
220 W
VCR Mode
5
6
22 kW
3
4
22 kW
1
2
21
22 kW
(1) These capacitors are optional.
Figure 42. Low-Cost SCART Switching System Circuit
24
Submit Documentation Feedback
Product Folder Link(s): THS7374
Copyright © 2008, Texas Instruments Incorporated