STMICROELECTRONICS TSH346ID

TSH346
Triple video buffer/filter for HD video applications
Features
■
6th order filtering of 36 MHz
■
5 V single-supply operation
■
Internal input DC level shifter
■
No input capacitor required
■
Three matched 6 dB amplifiers
■
AC or DC output-coupled
■
Very low harmonic distortion
■
Specified for 150 Ω loads
■
Minimum and maximum data is tested during
production
SO-8
(plastic package)
Pin1 identification
Top View
Applications
■
High-end video systems
■
High definition TV (HDTV)
■
Broadcast and graphic video
■
Multimedia products
R in 1
36MHz
LPF
+
6dB
8 R out
G in 2
36MHz
LPF
+
6dB
7 G out
B in 3
36MHz
LPF
+
6dB
6 B out
+VCC 4
DC Shifter
5 GND
Description
The TSH346 is a triple single-supply video buffer
featuring an internal gain of 6 dB and a 36 MHz
filtering for HD video outputs on 75-Ω video lines.
The TSH346 is ideal to drive either YUV, YPbPr or
RGB signals from video DAC outputs. The main
advantage of this circuit is that its input DC level
shifter allows for video signals on 75-Ω video lines
without damaging the synchronization tip of the
video signal, and with no input capacitor, while
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. This level is as low as possible to minimize
the output DC level in the video line.
The TSH346 is available in an SO-8 plastic
package for optimum space saving.
December 2008
Rev 2
1/18
www.st.com
18
Absolute maximum ratings and operating conditions
TSH346
1
Absolute maximum ratings and operating conditions
Table 1.
Absolute maximum ratings (AMR)
Symbol
VCC
Vin
Parameter
Supply voltage (1)
Input voltage range
(2)
Value
Unit
6
V
2.5
V
Toper
Operating free air temperature range
-40 to +85
°C
Tstd
Storage temperature
-65 to +150
°C
Maximum junction temperature
150
°C
Rthjc
SO8 thermal resistance junction to case
28
°C/W
Rthja
SO8 thermal resistance junction to ambient area
150
°C/W
Pmax.
Maximum power dissipation (at Tamb = 25° C) for Tj = 150° C
1
W
ESD
CDM: charged device model
HBM: human body model
MM: machine model
500
2
100
V
kV
V
Value
Unit
4.5 to 5.5 (1)
V
Tj
1. All voltage values, except the differential voltage, are with respect to the network terminal.
2. The magnitude of the input and output voltages must never exceed VCC +0.3 V.
Table 2.
Operating conditions
Symbol
VCC
Parameter
Power supply voltage
1. Tested in full production with a +5 V single power supply.
2/18
TSH346
Electrical characteristics
2
Electrical characteristics
Table 3.
VCC = +5 V single supply, Tamb = 25° C (unless otherwise specified)
Symbol
Parameter
Test conditions
Min.
Typ.
Max.
100
240
440
Unit
DC performance
VDC
Output DC shift
Iib
Input bias current
Rin
Input resistance
Cin
Input capacitance
ICC
Total supply current
G
DC voltage gain
RL = 150 Ω, Tamb
mV
-40° C < Tamb < +85° C
310
Tamb , input to GND
1.3
-40° C < Tamb < +85° C
1.4
3.6
μA
1
MΩ
0.1
pF
No load, input to GND
44.6
-40° C < Tamb < +85° C
45
51.6
mA
RL = 150 Ω, Vin = 0.5 V
1.96
2
2.05
V/V
-40° C < Tamb < +85° C
1.96
Output characteristics
VOH
High level output voltage
VOL
Low level output voltage
RL = 150 Ω
3.4
V
-40° C < Tamb < +85° C
3.8
RL = 150 Ω
47
76
Isource
IOUT
-40° C < Tamb < +85° C
mV
100
91
mA
106
Isink
3.9
134
-40° C < Tamb < +85° C
126
Small signal, VICM = 0.5 V,
RL = 150 Ω
-3 dB bandwidth
-1 dB bandwidth
25
36
32
25
32
dB
0.5
ns
86
nV/√ Hz
Filtering
Bandwidth
High
definition
Attenuation
D
Small signal, F = 74.25 MHz
VICM = 0.5 V, RL = 150 Ω
Delay between each channel
MHz
Noise
eN
Total input voltage noise
F = 100 kHz, RIN = 50 Ω
3/18
Electrical characteristics
Figure 1.
TSH346
Filtering
Figure 2.
10
6.2
0
6.0
Filter response (dB)
Filter response (dB)
Gain flatness
-10
-20
-30
5.6
5.4
Vcc=5V
small signal
Load=150Ω
-40
5.8
-50
1M
Vcc=5V
small signal
Load=150 Ω
5.2
10M
100M
1M
Frequency (Hz)
Figure 3.
Distortion 1 MHz (HD)
Figure 4.
0
-10
-20
Vcc=5V
F=1MHz
Load=150 Ω
-10
-20
HD2 & HD3 (dBc)
HD2 & HD3 (dBc)
Distortion 10 MHz (HD)
0
-30
-40
-50
-60
HD2
-70
-80
Vcc=5V
F=10MHz
Load=150 Ω
-30
-40
-50
HD2
-60
-70
-80
HD3
HD3
-90
-100
0.0
-90
0.5
1.0
1.5
2.0
2.5
3.0
3.5
-100
0.0
4.0
0.5
1.0
Output Amplitude (Vp-p)
Figure 5.
1.5
2.0
2.5
3.0
3.5
4.0
Output Amplitude (Vp-p)
Input noise vs. frequency
Figure 6.
1000
Channel crosstalk vs. frequency
-40
Vcc=5V
No load
-45
Input: 1Vp-p
Vcc=5V
Load=150Ω
-50
Gain (dB)
Input Noise (nV/VHz)
10M
Frequency (Hz)
100
-55
-60
-65
-70
100
1k
10k
Frequency (Hz)
4/18
100k
1M
-75
1M
10M
Frequency (Hz)
100M
TSH346
Electrical characteristics
Figure 7.
Gain vs. input amplitude
Figure 8.
Output vs input amplitude
5.0
2.10
Vcc=5V
Load=150Ω
4.5
Vcc=5V
Load=150Ω
4.0
VOH
2.05
Vout (V)
Gain (V/V)
3.5
2.00
3.0
2.5
2.0
1.5
1.95
1.0
0.5
Output DCshift
1.90
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0.0
0.0
1.4
0.2
0.4
0.6
0.8
Vin (Vp-p)
Figure 9.
1.0
1.2
1.4
1.6
1.8
2.0
Vin (V)
Current consumption vs. supply
Figure 10. Supply current vs. temperature
50
50
Vcc=5V
no Load
49
40
Vcc=5V
no Load
48
Icc (mA)
Icc (mA)
47
30
20
46
45
44
43
10
42
41
0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
40
-40
5.0
-20
Vcc (V)
Figure 11.
Filtering vs. temperature
60
80
60
Vcc=5V
Load=150Ω
55
Vcc=5V
Load=150Ω
50
Attenuation (dB)
-1dB Bandwidth (MHz)
40
Figure 12. Filter attenuation vs. temperature
50
45
40
35
45
40
30
25
25
-20
0
20
40
Temperature (°C)
60
80
HD, f=74.25MHz
35
30
20
-40
20
Temperature (°C)
60
55
0
20
-40
-20
0
20
40
60
80
Temperature (°C)
5/18
Electrical characteristics
TSH346
Figure 13. Gain matching vs. temperature
Figure 14. Output DC shift vs. temperature
5
400
Vcc=5V
Load=150 Ω
Vcc=5V
Load=150Ω
375
350
4
DCshift (mV)
325
MG (%)
3
2
300
275
250
225
200
175
1
150
125
0
-40
-20
0
20
40
60
100
-40
80
-20
0
Temperature (°C)
20
40
60
80
60
80
60
80
Temperature (°C)
Figure 15. Isink vs. temperature
Figure 16. Isource vs. temperature
150
120
140
110
130
100
Isource (mA)
Isink (mA)
120
110
100
90
80
90
80
70
70
60
60
Vcc=5V
Vcc=5V
50
-40
-20
0
20
40
60
50
-40
80
-20
Temperature (°C)
Figure 17.
20
40
Temperature (°C)
Ibias vs. temperature
Figure 18. VOH vs. temperature
4.00
2.0
1.8
0
Vcc=5V
3.95
1.6
3.90
3.85
1.2
VOH (V)
Ibias (μA)
1.4
1.0
0.8
3.80
3.75
0.6
3.70
0.4
3.65
0.2
0.0
-40
-20
0
20
40
Temperature (°C)
6/18
60
80
3.60
-40
Vcc=5V
Load=150Ω
-20
0
20
40
Temperature (°C)
TSH346
Electrical characteristics
Figure 19. VOL vs. temperature
Figure 20. Gain vs. temperature
2.20
60
2.15
55
2.10
Gain (dB)
VOL (mV)
50
45
2.05
2.00
1.95
40
1.90
35
30
-40
Vcc=5V
Load=150Ω
-20
1.85
0
20
40
Temperature (°C)
60
80
1.80
-40
Vcc=5V
Load=150Ω
-20
0
20
40
60
80
Temperature (°C)
7/18
Power supply considerations and improvement of the PSRR
3
TSH346
Power supply considerations and improvement of the
PSRR
Correct power supply bypassing is very important to optimize performance in low and highfrequency ranges. Bypass capacitors should be placed as close as possible to the IC pin
(pin 4) to improve high-frequency bypassing. A capacitor (CLF) greater than 10 µF is
necessary to improve the PSRR in low frequencies. For better quality bypassing, a capacitor
of 100 nF (CHF) can be added. CHF must be placed as close as possible to the IC pin, to
improve the noise supply rejection in the higher frequency ranges. A coil can be added in
order to better reject the noise from the supply and to prevent current peaks as much as
possible.
Figure 21. Circuit for power supply bypassing
+VCC
Coil
CLF
+
CHF
4
R
G
TSH346
B
5
AM00824
8/18
TSH346
Power supply considerations and improvement of the PSRR
Figure 22. Circuit for noise rejection improvement measurement
S
R
+5 V
T-bias
+
Coil
CLF
AGILENT
4395A
CHF
50 7
A
TSH346
50 7
AM00825
Figure 23 shows how the power supply noise rejection evolves versus frequency depending
on how carefully the power supply decoupling is achieved.
Figure 23. Power supply noise rejection
0
Noise rejection ratio (dB)
-10
-20
Vcc=5V(dc)+0.2Vp-p(ac)
Decoupling capacitor: 10µF+100nF
Load=150Ω
Noise rejection=20 log (ΔVCC/ΔVout)
-30
no coil
-40
-50
-60
-70
-80
10k
coil=560µH
100k
1M
10M
100M
Frequency (Hz)
9/18
Using the TSH346 to drive YC, CVBS, YUV, YPbPr and RGB video components
4
TSH346
Using the TSH346 to drive YC, CVBS, YUV, YPbPr and
RGB video components
Figure 24. Implementation of the video driver on output video DACs
+5 V
Y
Video
DAC
Reconstruction
filtering
75 7
++
LPF
75 7cable
+ 6 dB
1 Vpp
TV
75 7
1 Vpp
2 Vpp
Pb
Video
DAC
Reconstruction
filtering
75 7
++
LPF
75 7cable
+ 6 dB
0.7 Vpp
75 7
0.7 Vpp
0.
1.4 Vpp
1.
Pr
Video
DAC
Reconstruction
filtering
LPF
75 7
++
+ 6 dB
75 7cable
0.7 Vpp
75 7
0.7 Vpp
0.
TSH346
1.4 Vpp
1.
GND
-5 V
AM00826
10/18
TSH346
Using the TSH346 to drive YC, CVBS, YUV, YPbPr and RGB video components
Figure 25. Shapes of HD video signals coming from DACs including the synchronization tip
(Y signal)
White (100IRE)
54 ns
(4t)
27 ns
(2t)
27 ns
(2t)
Image content
590 ns
(44 t)
300 mV
Black (30IRE)
300 mV
590 ns
(44 t)
14.8 us (110 0t): 1920/1080i
24.3 us (180 0t): 1280/720i
GN D
s yn c.t ip
•Fclock=74.25 MHz
•t=1/Fclock=13.5 ns
AM00827
The TSH346 is used to drive high definition video signals up to 30 MHz. It can drive
components such as YPbPr and RGB where the bottom of the signal is close to zero volts.
An internal input DC value is added to the video signal in order to shift the bottom from GND.
The shift is not based on the average of the signal, but is an analog summation of a DC
component to the video signal. Therefore, no input capacitors are required. This provides a
real advantage in terms of cost and board space.
Under these conditions, it is possible to drive the signal in single supply with no saturation of
the driver against the lower rail.
Because half of the signal is lost through output impedance matching, in order to correctly
drive the video line the shifted signal is multiplied by a gain of +2 or +6 dB.
11/18
Using the TSH346 to drive YC, CVBS, YUV, YPbPr and RGB video components
TSH346
Figure 26. Flexible solution for SD and HD signals
HD
DAC
+5V
R
TV
75Ω
Cable
75Ω
Cable
150Ω
DAC
150Ω
DAC
75Ω
G
B
TSH346
SO8
75Ω
75Ω
Cable
150Ω
RCA
SD
DAC
+5V
Y,G
SCART
R-G-B, Y-C-CVBS
75Ω
Cable
150Ω
DAC
DAC
75Ω
Pb,B,C
150Ω
Pr,R,CVBS
150Ω
SD
TSH173
TSH103
SO8
75Ω
Cable
75Ω
Cable
75Ω
75Ω
+5V
CVBS
DAC
150Ω
TSH122
SC70
Y-C
75Ω
Cable
75Ω
CVBS
12/18
75Ω
TSH346
4.1
Using the TSH346 to drive YC, CVBS, YUV, YPbPr and RGB video components
Output capacitor
The output can be either DC- or AC-coupled, and can be directly connected to the line via a
75-Ω resistor (4) (Figure 27). Alternatively, an output capacitor can be used to remove any
DC components in the load. Assuming a 150-Ω load, a coupling capacitor of 220 µF can be
used to provide a very low cut-off frequency close to 5 Hz (Figure 28).
Figure 27. IDC output coupling (1 of 3 channels)
+5V
75 7
Video
DAC
75 7cable
TSH346
75 7
150 7
AM00828
Figure 28. AC output coupling (1 of 3 channels)
+5V
75 7
Video
DAC
TSH346
C = 220 µF
75 7 cable
+
75 7
150 7
CS
AM00829
1. CS is a 100 nF used to decrease the parasitic components of C in high frequencies.
2. The 75-Ω resistor must be as close as possible to the output of the driver to minimize the effect of parasitic
capacitance.
13/18
Package information
5
TSH346
Package information
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK® is an ST trademark.
14/18
TSH346
Package information
Figure 29. SO-8 package mechanical drawing
Table 4.
SO-8 package mechanical data
Dimensions
Ref.
Millimeters
Min.
Typ.
A
Inches
Max.
Min.
Typ.
1.75
0.069
A1
0.10
A2
1.25
b
0.28
0.48
0.011
0.019
c
0.17
0.23
0.007
0.010
D
4.80
4.90
5.00
0.189
0.193
0.197
E
5.80
6.00
6.20
0.228
0.236
0.244
E1
3.80
3.90
4.00
0.150
0.154
0.157
e
0.25
Max.
0.004
0.010
0.049
1.27
0.050
h
0.25
0.50
0.010
0.020
L
0.40
1.27
0.016
0.050
L1
k
ccc
1.04
0
0.040
8°
0.10
1°
8°
0.004
15/18
Ordering information
6
TSH346
Ordering information
Table 5.
Order codes
Part number
TSH346ID
TSH346IDT
16/18
Temperature
range
Package
-40°C to +85°C
SO-8
Packing
Marking
Tube
TSH346I
Tape & reel
TSH346I
TSH346
7
Revision history
Revision history
Table 6.
Document revision history
Date
Revision
Changes
29-May-2007
1
Initial release.
16-Dec-2008
2
Added curves in Chapter 2: Electrical characteristics.
Added all test limits in Table 3.
17/18
TSH346
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18/18