Datasheet

TYPICAL CONFIGURATION AND VIDEO
75 W
S-VideoY'Out
CVBS
R
SOC/DAC/Encoder
S-Video Y’
R
S-Video C’
R
Y'/G'
R
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
SD1OUT
SD2OUT
SD3OUT
DisableSD
GND
DisableHD
HD1OUT
HD2OUT
HD3OUT
BypassHD
SD1IN
SD2IN
SD3IN
NC
V
S+
NC
HD1IN
HD2IN
HD3IN
BypassSD
THS7365
Bypass
SDLPF
Bypass
HDLPF
P' /B'
B
R
CVBS
P' /R'
R
R
75 W
75 W
S-VideoC'Out
75 W
75 W
75 W
Y'/G'Out
75 W
P' /B'Out
B
75 W
75 W
P' /R'Out
R
75 W
75 W
75 W
+2.7Vto
+5V
DisableHD
DisableSD
THS7365
www.ti.com .................................................................................................................................................................................................. SBOS467 – MARCH 2009
the definition of luminance as stipulated by the
TERMINOLOGY International Commission on Illumination (CIE) . Video
departs from true luminance because a nonlinear
A typical application circuit using the THS7365 as a
term, gamma, is added to the true RGB signals to
video buffer is shown in Figure 116 . It shows a DAC
form R ’ G ’ B ’ signals. These R ’ G ’ B ’ signals are then
or encoder driving the input channels of the
used to mathematically create luma (Y ’ ). Thus,
THS7365. One channel is a CVBS connection while
luminance (Y) is not maintained, providing a
two other channels are for the S-Video Y ’ /C ’ signals
difference in terminology.
of an SD video system. These signals can be NTSC,
PAL, or SECAM signals. The other three channels This rationale is also used for the chroma ( C ’ ) term.
are the component video Y ’ /P ’
B
/P ’
R
(sometimes Chroma is derived from the nonlinear R ’ G ’ B ’ terms
labeled Y ’ U ’ V ’ or incorrectly labeled Y ’ /C ’
B
/C ’
R
) and, thus, it is nonlinear. Chominance ( C) is derived
signals. These signals are typically 720p, 1080i, or up from linear RGB, giving the difference between
to 1080p30 signals. If the video DAC / SOC samples chroma (C ’ ) and chrominance (C). The color
at greater than 74.25 MHz, then 480i/576i or difference signals (P ’
B
/P ’
R
/U ’ /V ’ ) are also referenced
480p/576p signals are also supported while in this manner to denote the nonlinear (gamma
effectively minimizing DAC images. Because the corrected) signals.
filters can be bypassed, other formats such as
1080p60 (also known as Full-HD or True-HD) and
R'G'B' video up to UWXGA can also be supported
with the THS7365.
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
Figure 116. Typical Six-Channel System Inputs from DC-Coupled Encoder/DAC with DC-Coupled Line
Driving
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