TSH345
Triple video buffer with selectable filter for HD and SD video applications
Preliminary Data
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
SO14
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 either Y-C, CVBS, Y-U-V, Y-Pb-Pr or R-G-B signals from video DAC outputs. The main advantage of this circuit is its input DC level shifter. It allows you to drive video signals on 75 Ω video lines without damage to the synchronization tip, and without either input or output 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 in the best position for the greatest linearity. The TSH345 is available in the SO14 plastic package for optimum space-saving.
May 2007
Rev 1
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www.st.com 14
This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change without notice.
Absolute maximum ratings and operating conditions
TSH345
1
Table 1.
Symbol VCC Vin Toper Tstg Tj Rthjc
Absolute maximum ratings and operating conditions
Absolute maximum ratings (AMR)
Parameter Supply voltage (1) Input voltage range
(2)
Value 6 TBD -40 to +85 -65 to +150 150 22 32 125 110 1 1.1 200 2 200
Unit V V °C °C °C °C/W
Operating free air temperature range Storage temperature Maximum junction temperature Thermal resistance junction to case SO14 TSSOP14 Thermal resistance junction to ambient area SO14 TSSOP14 Maximum power dissipation (@Tamb = 25°C) for Tj = 150° C SO14 TSSOP14 CDM: charged device model HBM: human body model MM: machine model
Rthja
°C/W
Pmax
W V kV V
ESD
1. All voltage values, except differential voltage, are with respect to network terminal. 2. The magnitude of input and output voltage must never exceed VCC +0.3 V.
Table 2.
Symbol VCC
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.
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TSH345
Electrical characteristics
2
Electrical characteristics
Table 3.
Symbol DC performance Output DC shift , RL = 150 Ω Tamb -40° C < Tamb < +85° C Input bias current Tamb , input to GND -40° C < Tamb < +85° C Input resistance, Tamb Input capacitance, Tamb Total supply current No load, input to GND -40°C < Tamb < +85°C Power supply rejection ratio 20 log (ΔVout/ΔVCC) Input to GND, RL = 150 Ω ΔVCC : 100 mVp/F = 1 MHz, CLF = 470 nF, CHF = 100 µF DC voltage gain RL = 150Ω, Vin = 0.5V -40°C < Tamb < +85°C Variation of the DC voltage gain between inputs of 0.3 V and 1 V Input step from 0.3 V to 1 V Gain matching between 3 channels, input = 1 V Gain matching between 3 channels, input = 0.3 V 1.94
Electrical characteristics at VCC = +5 V single supply, Tamb = 25°C (unless otherwise specified)
Test conditions Min. Typ. Max. Unit
VDC
197
329 405 1.5 2.38 12.6 0.1
389
mV
Iib Rin Cin ICC
0.85
2.9
µA GΩ pF
50.7 TBD
65
mA
PSRR
-70
dB
G
1.99 2 0.2 0.5 0.5
2.02
V/V
DG MG1 MG0.3
0.5 1 1
% % %
Output characteristics High level output voltage RL = 150 Ω -40° C < Tamb < +85° C Low level output voltage(1) RL = 150 Ω -40° C < Tamb < +85° C Isource Tamb -40° C < Tamb < +85° C Isink -40° C < Tamb < +85° C 46 79 TBD 145 102 mA
VOH
3.84
3.87 TBD 33 TBD 91 40
V
VOL
mV
mA
Iout
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Electrical characteristics Table 3.
Symbol Filtering Bandwidth F1 selected, small signal, VICM= 0.5 V, RL = 150 Ω 3 dB bandwidth 1 dB bandwidth Standard definition Flatness F1selected/F= 6 MHz, small signal, VICM = 0.5 V, RL = 150 Ω Attenuation F1 selected/F=27 MHz, small signal, VICM = 0.5 V, RL = 150 Ω Bandwidth F2 selected, small signal, VICM = 0.5 V, RL = 150 Ω 3 dB bandwidth 1 dB bandwidth 30
TSH345
Electrical characteristics at VCC = +5 V single supply, Tamb = 25°C (unless otherwise specified) (continued)
Test conditions Min. Typ. Max. Unit
5.12
9.3 7.3 0.5
MHz
dB
47
dB
Standard definition Flatness with progressive F2 selected/F=12 MHz small signal, VICM = 0.5 V, scanning RL = 150 Ω Attenuation F2 selected/F=54 MHz, small signal, VICM = 0.5 V, RL = 150 Ω
10.4
21.5 18.2 0.36
MHz
dB
34
42.7
dB
Bandwidth F3 selected, small signal, VICM = 0.5 V, RL = 150 Ω 3 dB bandwidth 1 dB bandwidth High definition Flatness F3 selected/F=30 MHz, small signal, VICM = 0.5 V, RL = 150 Ω Attenuation F3 selected/F=74.25 MHz, small signal, VICM = 0.5 V, RL = 150 Ω D gd Δg ΔΦ Delay between each channel Group delay variation F1 selected/F=0 to 6 MHz Differential gain F1 selected/F=6 MHz, RL = 150 Ω Differential phase F1 selected/F=6 MHz, RL = 150 Ω
22
35.6 30.8 0.46
MHz
dB
TBD
36 0.5 10.3 0.5 0.5
dB ns ns % °
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TSH345 Table 3.
Symbol Noise and distortion Total input voltage noise in Standard Definition F = 100 kHz, RIN = 50 Ω Total input voltage noise in High Definition F = 100 kHz, RIN = 50 Ω HD2 HD3 2nd harmonic distortion F1 selected/F=1 MHz, Vout = 2 Vp-p, RL = 150 Ω 3rd harmonic distortion F1 selected/F=1 MHz, Vout = 2 Vp-p, RL = 150 Ω
Electrical characteristics Electrical characteristics at VCC = +5 V single supply, Tamb = 25°C (unless otherwise specified) (continued)
Test conditions Min. Typ. Max. Unit
70 nV/√ Hz 93 -44 -63 dBc dBc
eN
Standby mode ISTBY Ton Toff Total current consumption in standby mode Fs1=1, Fs0=1 Time from standby to active mode Time from active to standby mode TBD 5 5 570 µA µs µs
Fs1, Fs0 and Mux features Vhigh Vlow High level Low level 0.9 0.3 V V
1. Simulated data.
Table 4.
Fs1 0 0 1 1
Filter and standby settings, VCC = +5 V single supply, Tamb = 25°C
Fs0 0 1 0 1 F3 F2 F1 Standby Settings Filtering for high definition (HD), 36 MHz Filtering for progressive video (PV), 18 MHz Filtering for standard definition (SD), 9 MHz TSH345 in standby mode
Fs1 and Fs0 floating: forbidden (for proper behavior of the TSH345, the Fs1 and Fs0 pins must never be left floating)
Table 5.
Mux settings, VCC = +5 V single supply, Tamb = 25°C
Mux 0 1 R1 G1 B1 R2 G2 B2 R1 G1 B1 Settings Video1 selected Video2 selected Video1 selected
Floating
MUX floating: forbidden (for proper behavior of the TSH345, the MUX pin must never be left floating)
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Power supply considerations
TSH345
3
Power supply considerations
Correct power supply bypassing is very important for optimizing performance in low and high-frequency 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 100 µF is necessary to improve the PSRR in low frequencies. For better quality bypassing, you can add a capacitor of 470 nF (CHF), also placed as close as possible to the IC pin, to improve the PSRR in the higher frequencies. Figure 1. Circuit for power supply bypassing
+VCC CLF + CHF
4
R in G in B in TSH345 R out G out B out
5
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TSH345
Using the TSH345 to drive Y-C, CVBS, Y-U-V, Y-Pb-Pr and R-G-B video components
4
Using the TSH345 to drive Y-C, CVBS, Y-U-V, Y-Pb-Pr and R-G-B video components
Figure 2. Implementation of the video driver on output video DACs
+5V
Video DAC
Y
1Vpp
Reconstruction Filtering
LPF
+
+6dB
75Ω
75Ω Cable
1Vpp
TV
75Ω
2Vpp
Video DAC
Pb
0.7Vpp
Reconstruction Filtering
LPF
+
+6dB
75Ω
75Ω Cable
0.7Vpp
75Ω
1.4Vpp
Video DAC
Pr
0.7Vpp
Reconstruction Filtering
LPF
+
+6dB
TSH345
75Ω
75Ω Cable
0.7Vpp
75Ω
1.4Vpp
-5V
GND
Figure 3.
Shapes of video signals coming from DACs (example for a black picture)
54ns (4t) 27ns (2t) 27ns (2t) •Fclock=74.25MHz •t=1/Fclock=13.5ns 300mV
Black (30IRE) 590ns (44t)
HD
300mV
590ns (44t)
14.8us (1100t): 1920/1080i 24.3us (1800t): 1280/720i
GND
sync.tip
160ns 150ns
Black (30IRE)
SD
300mV 4.6us 64us
GND
sync.tip
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Using the TSH345 to drive Y-C, CVBS, Y-U-V, Y-Pb-Pr and R-G-B video components Figure 4. Flexibility of the TSH345 for SD and HD signals
+5V
TSH345
HD/PV/SD Y,G DAC
150Ω
75Ω
150Ω
TV
Cable
75Ω
DAC
Pb,B
150Ω
75Ω TSH345
TSSOP14 SO14
Cable
75Ω
DAC
Pr,R
150Ω
150Ω
75Ω
Cable
75Ω
150Ω
DAC
Y,G Pb,B,C Pr,R,CVBS
Mux Filter select Standby
DAC
DAC
HD/PV/SD Y,G DAC
150Ω
+5V
75Ω
TV
Cable
75Ω
NC
75Ω
DAC
Pb,B,C
150Ω
Cable
75Ω
NC
DAC
Pr,R,CVBS
150Ω
TSH345
TSSOP14 SO14
75Ω
Cable
75Ω
NC
Mux (NC) Filter select Standby
The TSH345 is used to drive either high definition video signals up to 30 MHz, or progessive and interlaced standard definition video signals on 75-ohm video lines. It can drive a large panel of signals like Y-C and CVBS, Y-U-V, Y-Pb-Pr and R-G-B where the bottom of the signal (the synchronization tip in the case of Y and CVBS signals) 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, which provides a real advantage in terms of cost and board space. Under these conditions, it is possible to drive the signal in single supply without any saturation of the driver against the lower rail. Because half of the signal is lost through output impedance matching, in order to properly drive the video line, the shifted signal is multiplied by a gain of 2 or +6 dB.
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TSH345
Using the TSH345 to drive Y-C, CVBS, Y-U-V, Y-Pb-Pr and R-G-B video components
4.1
Output capacitor
The output can be either DC-coupled or AC-coupled. The output can be connected to the line via a 75-ohm resistor directly (see Figure 5). Or, an output capacitor can be used to remove any DC components in the load. Assuming the load is 150-ohm, a coupling capacitor of 220 µF can be used to provide a very low cut-off frequency close to 5 Hz (see Figure 6). Figure 5. DC output coupling (1 of 3 channels)
+5V
Video DAC
75Ω
TSH345
75Ω Cable
150Ω
75Ω
Figure 6.
AC output coupling (1 of 3 channels)
+5V
Video DAC
75
TSH345
C=220µF
+
75 Cable
150
CS
75
1. CS is a 100nF used to decrease the parasitic components of C in high frequencies. 2. The 75-ohm resistor must be as close as possible to the output of the driver to minimize the effect of parasitic capacitance.
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Package information
TSH345
5
Package information
In order to meet environmental requirements, STMicroelectronics offers these devices in ECOPACK® packages. These packages have a lead-free second level interconnect. The category of second level interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an STMicroelectronics trademark. ECOPACK specifications are available at: www.st.com.
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TSH345
Package information
5.1
SO-14 package
Dimensions Ref. Min. A a1 a2 b b1 C c1 D E e e3 F G L M S 3.8 4.6 0.5 8.55 5.8 1.27 7.62 4.0 5.3 1.27 0.68 8° (max.) 0.149 0.181 0.019 8.75 6.2 0.35 0.19 0.5 45° (typ.) 0.336 0.228 0.050 0.300 0.157 0.208 0.050 0.026 0.344 0.244 0.1 Millimeters Typ. Max. 1.75 0.2 1.65 0.46 0.25 0.013 0.007 0.019 0.003 Min. Inches Typ. Max. 0.068 0.007 0.064 0.018 0.010
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Package information
TSH345
5.2
TSSOP14 package
Dimensions Ref. Min. A A1 A2 b c D E E1 e K L1 0° 0.45 0.60 0.05 0.8 0.19 0.09 4.9 6.2 4.3 5 6.4 4.4 0.65 BSC 8° 0.75 0° 0.018 0.024 1 Millimeters Typ. Max. 1.2 0.15 1.05 0.30 0.20 5.1 6.6 4.48 0.002 0.031 0.007 0.004 0.193 0.244 0.169 0.197 0.252 0.173 0.0256 BSC 8° 0.030 0.004 0.039 Min. Inches Typ. Max. 0.047 0.006 0.041 0.012 0.0089 0.201 0.260 0.176
A
A2 A1 b e K c L E
D
E1
PIN 1 IDENTIFICATION
1
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TSH345
Ordering infomation
6
Ordering infomation
Table 6. Order codes
Temperature range -40°C to +85°C Package SO14 TSSOP14 Packing Tube Tape & reel Tape & reel Marking TSH345I TSH345I TSH345I
Part number TSH345ID TSH345IDT TSH345IPT
7
Revision history
Date 29-May-07 Revision 1 Changes Preliminary data, initial release.
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TSH345
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