THS7364_14 Datasheet, PDF (28/49 Pages) Texas Instruments – 6-Channel Video Amplifier with 3 SD and 3 Full-HD Filters with 6-dB Gain

THS7364
SBOS530 – AUGUST 2010
TYPICAL CONFIGURATION AND VIDEO
TERMINOLOGY
A typical application circuit using the THS7364 as a
video buffer is shown in Figure 77. It shows a DAC or
encoder driving the input channels of the THS7364.
One channel is a CVBS connection while two other
channels are for the S-Video Y’/C’ signals of an SD
video system. These signals can be NTSC, PAL, or
SECAM signals. The other three channels are the
component video Y’/P’_B/P’_R (sometimes labeled
Y’U’V’ or incorrectly labeled Y’/C’_B/C’_R) signals. These
signals are typically 480i, 576i, 480p, 576p, 720p,
1080i, or up to 1080p60 signals. Because the filters
can be bypassed, other formats such as R'G'B' video
up to QXGA or UWXGA can also be supported with
the THS7364.
Note that the Y’ term is used for the luma channels
throughout this document rather than the more
common luminance (Y) term. This usage accounts for
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the definition of luminance as stipulated by the
International Commission on Illumination (CIE). Video
departs from true luminance because a nonlinear
term, gamma, is added to the true RGB signals to
form R’G’B’ signals. These R’G’B’ signals are then
used to mathematically create luma (Y’). Thus,
luminance (Y) is not maintained, providing a
difference in terminology.
This rationale is also used for the chroma (C’) term.
Chroma is derived from the nonlinear R’G’B’ terms
and, thus, it is nonlinear. Chominance (C) is derived
from linear RGB, giving the difference between
chroma (C’) and chrominance (C). The color
difference signals (P’_B/P’_R/U’/V’) are also referenced
in this manner to denote the nonlinear (gamma
corrected) signals.
CVBS
S-Video Y’
S-Video C’
Y'/G'
P'_B/B'
P'_R/R'
THS7364
1 SD1 IN
SD1 OUT 20
R
2 SD2 IN
SD2 OUT 19
3 SD3 IN
SD3 OUT 18
4 NC
R
+2.7 V to
+5 V
5 V_S+
6 NC
Disable SD 17
GND 16
Disable FHD 15
Disable SD
Disable FHD
7 FHD1 IN FHD1 OUT 14
R
8 FHD2 IN FHD2 OUT 13
9 FHD3 IN FHD3 OUT 12
10 Bypass SD Bypass FHD 11
R
Bypass
SD LPF
R
Bypass
FHD LPF
CVBS
75 W
S-Video Y' Out
75 W
S-Video C' Out
75 W
Y'/G' Out
75 W
P'_B/B' Out
75 W
P'_R/R' Out
R
75 W
75 W
75 W
75 W
75 W
75 W
75 W
(1) Figure 77. Typical Six-Channel System Inputs from DC-Coupled Encoder/DAC with DC-Coupled Line
Driving
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