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December 2008 Rev 1 1/23
23
TSH345
Triple video buffer with selectable filter
for HD and SD video applications
Features
■ Selectable 6th order filtering of 36 MHz,
18 MHz and 9 MHz
■ 5 V single-supply operation
■ Internal input DC level shifter
■ No input capacitor required
■ 3 matched 6 dB amplifiers
■ AC or DC output-coupled
■ Very low harmonic distortion
■ Specified for 150 Ω loads
■ Data min. and max. are tested during
production
Applications
■ High-end video systems
■ High definition TV (HDTV)
■ Broadcast and graphic video
■ Multimedia products
Description
The TSH345 is a triple single-supply video buffer
featuring an internal gain of 6 dB and selectable
filtering for HD and SD video outputs on 75 Ω
video lines. The TSH345 is ideal to drive YC,
CVBS, YUV, YPbPr or RGB signals from video
DAC outputs.
The main advantage of this circuit is its input DC
level shifter. It allows driving video signals on 75 Ω
video lines without damaging the synchronization
tip and without input or output capacitors when
using a single 5 V power supply. The DC level
shifter is internally fixed and optimized to keep the
output video signals between low and high output
rails in the best position for the greatest linearity.
The TSH345 is available in SO-14 and TSSOP-14
plastic packages for optimum space saving.
12
G out
1
R2 in
R out
+VCC
2
3
13
14
B out
R1 in
7
G1 in
GND
8
DC Shifter
6dB
6dB
+
36MHz
18MHz
9MHz
LPF
6dB
36MHz
18MHz
9MHz
LPF
36MHz
18MHz
9MHz
LPF
+
+
4
B1 in
5
6
G2 in
B2 in
11
10
9
Fs1
Mux
Fs0
MUX
MUXMUX
SO-14
TSSOP14
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