THS7365 Datasheet, PDF (33/53 Pages) Texas Instruments – 6-Channel Video Amplifier with 3-SD and 3-HD Sixth-Order Filters and 6-dB Gain

THS7365
www.ti.com.................................................................................................................................................................................................. SBOS467 – MARCH 2009
TYPICAL CONFIGURATION AND VIDEO
TERMINOLOGY
A typical application circuit using the THS7365 as a
video buffer is shown in Figure 116. It shows a DAC
or encoder driving the input channels of the
THS7365. 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 720p, 1080i, or up
to 1080p30 signals. If the video DAC / SOC samples
at greater than 74.25 MHz, then 480i/576i or
480p/576p signals are also supported while
effectively minimizing DAC images. Because the
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
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'
THS7365
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 HD 15
Disable SD
Disable HD
7 HD1 IN
HD1 OUT 14
R
8 HD2 IN
HD2 OUT 13
9 HD3 IN
HD3 OUT 12
10 Bypass SD Bypass HD 11
R
Bypass
SD LPF
R
Bypass
HD LPF
R
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
75 W
75 W
75 W
75 W
75 W
75 W
75 W
Figure 116. Typical Six-Channel System Inputs from DC-Coupled Encoder/DAC with DC-Coupled Line
Driving
Copyright © 2009, Texas Instruments Incorporated
Product Folder Link(s): THS7365
Submit Documentation Feedback
33