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
R2 in 2
G1 in 3
MUX
SO-14
TSSOP14
R1 in 1
MUX
36MHz
18MHz
9MHz
LPF
14 Fs0
+
6dB
13 Fs1
12 R out
Applications
■
■
■
■
G2 in 4
36MHz
18MHz
9MHz
LPF
+
6dB
11 G out
10 B out
High-end video systems
MUX
High definition TV (HDTV)
Broadcast and graphic video
Multimedia products
B1 in 5
B2 in 6
+VCC 7
36MHz
18MHz
9MHz
LPF
+
6dB
9 Mux
DC Shifter
8 GND
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.
December 2008
Rev 1
1/23
www.st.com
23
Absolute maximum ratings and operating conditions
TSH345
1
Table 1.
Symbol
V
CC
V
in
T
oper
T
stg
T
j
R
thjc
Absolute maximum ratings and operating conditions
Absolute maximum ratings
Parameter
Supply voltage
(1)
Input voltage range
Operating free air temperature range
Storage temperature
Maximum junction temperature
Thermal resistance junction to case
SO-14
TSSOP14
Thermal resistance junction to ambient area
SO-14
TSSOP14
Maximum power dissipation (at T
amb
= 25° C) for T
j
= 150° C
SO-14
TSSOP14
CDM: charged device model
HBM: human body model
MM: machine model
Value
6
2.5
-40 to +85
-65 to +150
150
22
32
125
110
1
1.1
250
2
100
Unit
V
V
°C
°C
°C
°C/W
R
thja
°C/W
P
max
W
V
kV
V
ESD
1. All voltage values, except differential voltage, are with respect to network terminal.
Table 2.
Symbol
V
CC
Operating conditions
Parameter
Power supply voltage
Value
4.5 to 5.5
(1)
Unit
V
1. Tested in full production with +5 V single power supply.
2/23
TSH345
Electrical characteristics
2
Electrical characteristics
Table 3.
Symbol
DC performance
V
DC
Output DC shift
,
R
L
= 150
Ω
T
amb
-40° C < T
amb
< +85° C
Input bias current
T
amb
, input to GND
-40° C < T
amb
< +85° C
Input resistance, T
amb
Input capacitance, T
amb
Total supply current (3 x operators)
No load, input to GND
-40°C < T
amb
< +85°C
DC voltage gain
R
L
= 150Ω, V
in
= 1.4V
-40°C < T
amb
< +85°C
1.96
100
240
310
1.3
1.4
1
0.1
44.6
45
2
1.96
51.6
440
mV
Electrical characteristics at V
CC
= +5 V single supply, T
amb
= 25°C
(unless otherwise specified)
Test conditions
Min.
Typ.
Max.
Unit
I
ib
R
in
C
in
I
CC
3.6
µA
MΩ
pF
mA
G
2.05
V/V
Output characteristics
V
OH
High level output voltage
R
L
= 150
Ω
-40° C < T
amb
< +85° C
Low level output voltage
R
L
= 150
Ω
I
source
T
amb
-40° C < T
amb
< +85° C
I
sink
-40° C < T
amb
< +85° C
Filtering
Bandwidth
F1 selected, small signal, V
ICM
= 0.5 V, R
L
= 150
Ω
-3 dB bandwidth
-1 dB bandwidth
Attenuation
F1 selected/F=27 MHz, small signal, V
ICM
= 0.5 V,
R
L
= 150
Ω
76
3.4
3.9
3.8
47
V
V
OL
mV
I
out
100
91
134
126
mA
106
mA
Standard
definition
5
40
9
5.7
45
MHz
dB
3/23
Electrical characteristics
Table 3.
Symbol
TSH345
Electrical characteristics at V
CC
= +5 V single supply, T
amb
= 25°C
(unless otherwise specified) (continued)
Test conditions
Bandwidth
F2 selected, small signal, V
ICM
= 0.5 V, R
L
= 150
Ω
-3 dB bandwidth
-1 dB bandwidth
Min.
Typ.
Max.
Unit
Standard
definition
with
progressive
Attenuation
scanning
F2 selected/F = 54 MHz, small signal,
V
ICM
= 0.5 V, R
L
= 150
Ω
13
32
21
18
38
MHz
dB
High
definition
Bandwidth
F3 selected, small signal, V
ICM
= 0.5 V, R
L
= 150
Ω
-3 dB bandwidth
-1 dB bandwidth
Attenuation
F3 selected/F = 74.25 MHz, small signal,
V
ICM
= 0.5 V, R
L
= 150
Ω
25
25
36
32
32
0.5
11
0.38
0.5
MHz
dB
ns
ns
%
°
D
gd
Δg
ΔΦ
Noise
Delay between each channel
Group delay variation
F1 selected/F = 0 to 6 MHz
Differential gain
F1 selected/F = 6 MHz, R
L
= 150
Ω
Differential phase
F1 selected/F = 6 MHz, R
L
= 150
Ω
eN
Total input voltage noise in Standard Definition
F = 100 kHz, R
IN
= 50
Ω
Total input voltage noise in High Definition
F = 100 kHz, R
IN
= 50
Ω
74
nV/√
Hz
86
Standby mode
Total current consumption in standby mode
Fs1 = 1, Fs0 = 1
T
amb
-40° C < T
amb
< +85° C
Time from standby to active mode
Time from active to standby mode
I
STBY
440
480
5
5
690
µA
T
on
T
off
µs
µs
Fs1, Fs0 and Mux features
V
high
V
low
High level
Low level
0.9
0.3
V
V
4/23
TSH345
Table 4.
Fs1
(1)
0
0
1
1
Electrical characteristics
Filter and standby settings, V
CC
= +5 V single supply, T
amb
= 25°C
Fs0
(1)
0
1
0
1
F3
F2
F3
Standby
Settings
Filtering for high definition (HD)
Filtering for progressive video (PV)
Filtering for standard definition (SD)
TSH345 in standby mode
1. Fs1 and Fs0 pins must never be left floating.
Table 5.
Mux settings, V
CC
= +5 V single supply, T
amb
= 25°C
Mux
(1)
0
1
R1 G1 B1
R2 G2 B2
Settings
Video1 selected
Video2 selected
1. The MUX pin must never be left floating.
5/23
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