THS7315 Datasheet, PDF (8/26 Pages) Texas Instruments – 3-Channel SDTV Video Amplifier with 5th-Order Filters and 5.2-V/V Gain

THS7315
SLOS532 – JUNE 2007
www.ti.com
APPLICATION INFORMATION (continued)
INPUT OVERVOLTAGE PROTECTION
The THS7315 is built using a very high-speed complementary bipolar and CMOS process. The internal junction
breakdown voltages are relatively low for these very small geometry devices. These breakdowns are reflected in
the Absolute Maximum Ratings table. All input and output device pins are protected with internal ESD protection
diodes to the power supplies, as shown in Figure 3.
V_S+
External
Input/
Output
Pin
Internal
Circuitry
Figure 3. Internal ESD Protection
These diodes provide moderate protection to input overdrive voltages above and below the supplies as well. The
protection diodes can typically support 30 mA of continuous current when overdriven.
TYPICAL CONFIGURATION and VIDEO TERMINOLOGY
A typical application circuit using the THS7315 as a video buffer is shown in Figure 4. It shows a video DAC
output, such as the DaVinci, driving the three input channels of the THS7315. Although the S-Video Y’/C’
channels and the composite video (CVBS) channel of an SD video system are shown, these channels can easily
be the Y’P’_BP’_R (sometimes labeled Y’U’V’ or incorrectly labeled Y’C’_BC’_R) signals of a 480i or 576i system.
These signals can also be G’B’R’ (R'G'B') signals or other variations. Note that for computer signals, the sync
should be embedded within the signal for a system with only three outputs. This configuration is sometimes
labeled as R’G’sB’ (sync on green) or R’sG’sB’s (sync on all signals).
DaVinci/
DM2xx/
DM3xx/
TM
OMAP
SDTV
CVBS
S-Video Y’
S-Video C’
480i/576i
Y’P’_BP’_R
G’B’R’
+1.8 V
CVBS
500 W
THS7315
330 mF _{75 W}
+
CVBS
OUT
75 W
Y’
500 W
C’
500 W
1 CH.1 IN
2 CH.2 IN
3 CH.3 IN
4 V_S+
CH.1 OUT 8
CH.2 OUT 7
CH.3 OUT 6
GND 5
0.1 mF
330 mF _{75 W}
+
S-Video
0.1 mF
75 W
+
Gain =
5.2 V/V
Y’
OUT
C’
OUT
75 W
+3.3 V ^{22 mF}
Figure 4. Typical SDTV CVBS/Y'/C' Inputs From DC-Coupled Encoder/DAC
With AC-Coupled Line Driving
75 W
8
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