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ZXFV4583
SYNC SEPARATOR WITH VARIABLE FILTER
DEVICE DESCRIPTION
The ZXFV4583 provides the ability to separate out video synchronization signals for a wide variety of TV and CRT display systems, standard and non-standard. Flexibility arises from the use of just three external resistors to adapt to each application. One resistor controls a fully integrated internal color carrier filter with variable bandwidth. This filter avoids disturbance from the color carrier, permitting accurate threshold slicing for timing extraction. A second resistor controls the voltage threshold for loss of signal detection after a time-out interval. The third resistor controls the timing functions. DC restoration for displays is facilitated by the Back Porch synch output, which can be used to drive an external circuit to clamp the blanking voltage to a fixed level.
FEATURES AND BENEFITS
* PAL, NTSC, SECAM * Variable filter for optimal accuracy * Sync outputs: composite, horizontal, vertical, back
porch, odd/even
* No-signal detector * On chip sample / hold capacitors * +5V single supply * Default vertical output where there are no
serration pulses
* Pin and layout compatible with part EL4583 in
SO16N surface mount package
APPLICATIONS
* Digital image capture * Video input systems requiring separation of
picture timing
ORDERING INFORMATION
Part Number ZXFV4583N16TA ZXFV4583N16TC Container Reel 7 Reel 13 Increment 500 2500
* Video distribution * CCTV surveillance * Digital multimedia * Timing for black level clamp
CONNECTION DIAGRAM
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ABSOLUTE MAXIMUM RATINGS
Supply voltage VCC Inputs to ground* Operating temperature range Storage Operating ambient junction temperature -0.5V to +7V -0.5V to VCC +0.5V -40 C to 85 C -65 C to +150 C TJMAX150 C**
**The thermal resistance from the semiconductor die to ambient is typically 120 C/W when the SO16 package is mounted on a PCB in free air. The power dissipation of the device when loaded must be designed to keep the device junction temperature below TJMAX. *During power-up and power-down, these voltage ratings require that signals be applied only when the power supply is connected.
ELECTRICAL CHARACTERISTICS
VCC = 5V, RSET = 681k , RFILT = 22k , RNOSIG = 82k , Tamb = 25 C unless otherwise stated. Test level: P = 100% production test C = Characterized only
PARAMETER DC Characteristics Supply current Clamp voltage at FILTIN Discharge current at FILTIN Discharge current at FILTIN Clamp charge current at FILTIN Clamp voltage at FVIDIN Discharge current at FVIDIN Discharge current at FVIDIN Clamp charge current at FVIDIN R SET voltage, pin 12 R FILT voltage, pin 1 RNOSIG current, pin 2 Logic output low voltage, V OL
CONDITIONS
TEST
MIN
TYP
MAX UNIT
P Pin 4 unloaded Pin 4, Vin = 2V pk-pk Pin 4, no signal Pin 4, Vin = 1V pk-pk Pin 8 unloaded Pin 8, Vin = 2V pk-pk Pin 8, no signal Pin 8, Vin = 1V pk-pk P C C P P C C P P P P I OL = 1.6mA P
2 1.2
4.5 1.35 1
6.5 1.5
mA V A
3 2 1.2
6 3 1.35 1
12 4 1.5
A mA V
3 2 1.5 0.35 1.5
6 3 1.75 0.5 2.5 0.35
12 4 2 0.65 3.5 0.8 mA V V A V
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ZXFV4583
ELECTRICAL CHARACTERISTICS (Cont.)
VCC = 5V, RSET = 681k , RFILT = 22k , RNOSIG = 82k , Tamb = 25 C unless otherwise stated.
PARAMETER AC Characteristics FILTIN function input voltage range Filter voltage gain Filter attenuation Slice level CSYNC prop. Delay, t CS VSYNC delay VSYNC pulse width, t VSYNC (PAL) VSYNC pulse width, t VSYNC (NTSC) VSYNC default delay, t VSD HSYNC delay HSYNC pulse width, t HSYNC BKPCH delay, t BD BKPCH pulse width, t B Relative to pin 4 input PAL/NTSC FILTIN to FILOUT 4.4MHz for PAL, 3.6MHz for NTSC Vin = 1V pk-pk Relative to pin 4 input P P P P P P C C C P P P P P 2.7 3.8 30 0.5 4.9 15 10 40 5.7 19 14 50 250 250 165 195 36 250 5 250 3.7 6.2 400 4.7 45 60 400 2 6.5 V pk-pk dB dB dB % ns ns s s s ns s ns s CONDITIONS TEST MIN TYP MAX UNIT
Note:
In order to avoid coupling between high speed logic output signals and analog inputs, the test circuit layout uses connections from the logic output pins routed away from the analog pins. In the application, similar care in the layout is required, keeping resistors RFILT, RNOSIG and RSET close to their respective pins, in particular routing signal CSYNC away from pins 1, 2 and 12.
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CONNECTIONS
PIN No. 1 PIN NAME R FILT TYPE Resistor control FUNCTION Controls the input color carrier filter characteristic. An external resistor R FILT connected from this pin to 0V sets the bandwidth. Smaller R FILT gives increased bandwidth. See the detailed operating description below. Controls the no-signal detector level. An external resistor R NOSIG connected from this pin to 0V sets the threshold voltage level, according to the equation V PMIN = 0.75 R NOSIG / R SET where V PMIN is the minimum detected sync pulse amplitude at pin 4 and R SET is the resistor value at pin 12. Composite sync logic output. Includes all sync pulses derived from the input video.
2
R NOSIG
Resistor control
3
CSYNC
Logic out
4
FILTIN
Input to color carrier filter. This is the main analog (unfiltered) composite video input used when color carrier filtering is required. A Analog in voltage clamp circuit and adaptive current source are also included at this node. See the detailed operating description. When the filter is not used, this pin must be left open circuit. Logic out Ground Vertical sync output. This is an active low pulse commencing on the first vertical sync pulse trailing (rising) edge and ending near the second next equalizing pulse. See timing diagram. Provides ground return path for internal logic output buffer circuits. Normally connected externally to a common PCB ground plane.
5 6 7
VSYNC OVD FILTOUT
Analog out Analog output signal from color carrier filter. The filter voltage gain is nominally 2. This output is normally capacitor-coupled to pin 8. Input for filtered analog video signal input. This is the direct input to the sample/hold and sync slicing comparator providing the logic Analog in timing edges. This input is normally coupled via an external capacitor from FILTOUT, pin 7. It may be used as the signal input where the color carrier filter is not required. Includes a clamp similar that of pin 4. Analog out Analog output, a positive voltage typically equal to twice the (negative) peak sync pulse amplitude if the filter is used. Logic out Logic output, which goes high after a time-out delay when no signal is present. The threshold level is controlled at pin 2. Burst or Back Porch logic output, an active low monostable pulse triggered from rising composite sync pulse edges. The width is set by R SET to overlap most of the steady part of the back porch, assuming the color carrier burst has been attenuated sufficiently by filtering. This pulse is then suitable for controlling an external black level clamping circuit. See the timing diagram. Controls the timing interval of the sample/hold circuit and the monostable interval for the sync outputs according to the application. An external resistor, R SET connected from this pin to 0V establishes the timing parameter, to which these times are scaled together. See the detailed operating description. Odd field logic output. High during an odd numbered field, low during even. This output is timed with the start of the VSYNC pulse. Power supply input, +5V. Horizontal sync logic output. Monostable output derived from CSYNC falling edges, it achieves a steady stream of 5s pulses. The half line events during the field blanking interval are eliminated. See timing diagram.
8
FVIDIN
9 10
VLEV NOSIG
11
BKPCH
Logic out
12
R SET
Resistor control
13 14 15
ODDFLD V+ HSYNC
Logic out Power in Logic out
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ZXFV4583
DETAILED DESCRIPTION Introduction
This device includes all the functions required to separate out the critical timing points of most types of video signal. A sample-and-hold process is used to establish accurately the 50% point of the sync pulse. The input is also filtered to avoid the effect of the color carrier. The filter is coupled externally. The following paragraphs give a simplified description of the signal processing. The vertical sync output VSYNC is derived from the Field pulse group. Where there are short equalization pulses in the standard systems, these short pulses are ignored. Essentially, a pulse width discriminator circuit senses the first of the Field pulses, as they are wider than those of the rest of the sequence. The trailing edge of the first negative-going Frame Pulse (i.e. the rising edge of the first "serration" pulse) triggers the VSYNC output. In systems with a frame interval with no serration pulses, a vertical sync output is provided after a default delay as in Figure 4. Also provided is an ODDFLD logic output, which is high during an odd-numbered field and low during an even one. The horizontal sync HSYNC is a monostable output derived from the leading (falling) edge of the composite sync. The pulse width is about 5 s. Also, during the Field blanking sequence, the additional half-line pulses are removed by a timing circuit with a pulse interval discrimination function controlled by RSET. RSET is normally set to 681k for standard PAL or NTSC timings. Consequently the scan rate is inversely proportional to RSET. The Back Porch monostable output BKPCH is initiated from the trailing edge of the composite sync. The pulse is active low and the width is set according to RSET.
Color carrier filter
This low-pass filter provides adjustable attenuation of the color carrier with low distortion of the remaining sync pulses so as to ensure accurate timing of the extracted logic outputs. The control is via an external resistor R FILT connected from pin 1 to ground. R FILT =22k gives corner frequency of 1.3MHz c o r r e s p ondi ng t o ~ 12dB at t enu a t i o n @ 3.58MHz.(Corner freq. Proportional to 1/R FILT , minimum value 18k ). A graph shows how the bandwidth varies with the resistor value.
Clamping circuits
Clamping circuits are use to limit the signal swing excursion after AC coupling at both the input to the filter, FILTIN and the timing extractor input, FVIDIN. In each case, the sync tip level is maintained at a value of nominally 1.35V.
Sync timing extraction circuits
The waveforms are depicted in Timing Diagrams, Figure 1 for PAL (625 lines) and Figure 2 for NTSC (525 lines). Sample-and-hold circuits are used to obtain time-delayed voltage values of the sync tip and the back porch. The sample gates are controlled by a comparator sensing the video input relative to a threshold at a fixed offset above the sync tip clamp level. The sampled voltages are combined in a potential divider to derive the mean voltage (50% amplitude), which is used as the sync pulse threshold. A second comparator then provides CSYNC, the logic version of the composite sync signal. This is delayed slightly as shown in Figure 3. The time delay comprises that of the input filter and also the smaller delay of the comparator and logic. The timing of the sample hold and other time parameters are all controlled together in unison by the external resistor RSET. A 1% resistor tolerance is recommended. The sync tip voltage level from the sample-and-hold is buffered and provided as an analog output, VLEV.
Loss-of-Signal detector
Loss of signal is indicated by a logic high level at the output NOSIG. The decision threshold is set by an external resistor RNOSIG connected from pin 2 to ground. RNOSIG =100k gives a shut off threshold of 250mV of sync amplitude at FVIDIN or ~130mV on FILTIN (Threshold proportional to RNOSIG, minimum value 82k ) The table of connections above gives the equation used to determine a suitable resistor value. A waiting time of nominally 600 s occurs before the loss of signal is flagged.
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ZXFV4583
FRAME 1 FIELD BLANKING VIDEO INPUT
620
621
622
623
624
625
1
2
3
4
5
6
7
8
23
CSYNC OUTPUT
VSYNC OUTPUT
HSYNC OUTPUT
BACK PORCH OUTPUT, BKPCH
SEE FIGURE 3 FOR DETAIL
Figure 1: PAL 625 TIMING DIAGRAM
VIDEO INPUT
523
524
525
1
2
3
4
5
6
7
8
9
10
11
20
CSYNC OUTPUT
VSYNC OUTPUT
HSYNC OUTPUT
BACK PORCH OUTPUT, BKPCH
Figure 2: NTSC TIMING DIAGRAM
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ZXFV4583
FVIDIN VIDEO INPUT
50%
tCS CSYNC OUTPUT
BKPCH OUTPUT
tBD
tB
Figure 3: SYNC SLICING & OUTPUT DETAIL
LINE PERIOD FVIDIN VIDEO INPUT
T VSD VSYNC OUTPUT
Figure 4: VERTICAL SYNC DEFAULT
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TYPICAL CHARACTERISTICS
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ZXFV4583
TYPICAL CHARACTERISTICS (Cont.)
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APPLICATIONS INFORMATION General guidance
The ZXFV4583 is a high speed mixed analog/digital s i g n a l pr oc e s s i ng c om pone nt re q u i r i n g t h e appropriate care in the layout of the application printed circuit board. A continuous ground plane construction is preferred. Suitable power supply decoupling suggested includes a 100nF leadless ceramic capacitor close to the power supply connection at pin 14. In order to avoid coupling between high speed logic output signals and analog inputs, the test circuit layout uses connections from the logic output pins routed away from the analog pins. In the application, similar care in the layout is required, keeping resistors, RFILT, RNOSIG, and RSET close to their respective pins, in particular routing signal CSYNC away from pins 1, 2 and 12.
Parts List
QTY CCTREF VALUE DESCRIPTION Resistors, surface mount 1 1 1 1 2 3 1 1 1 R1 R2 R3 R4 R5, R12 R6, R7, R8 R9 R10 R11 51 22k 82k 681k 2.2k 1k 130 33 24 0805 0805 0805 0805 0805 0805 0805 0805 0805
Capacitors, surface mount
Evaluation circuit
An evaluation circuit is available, designed to provide demonstration of the ZXFV4583 function using 50 test instruments. The schematic diagram is shown in Figure 5 and the printed circuit layout is shown in Figures 6, 7 and 8. The circuit includes the Zetex ZXFV4089 DC Restoration Circuit, which is described in the data sheet for that part. The ZXFV4089 uses the Back Porch output from the ZXFV4583 in order to control and stabilize the black level of a video waveform. BNC connector sockets allow connection of the analog video and output to laboratory test instruments via 50 BNC cables. The circuit can be adapted for 75 use. The output circuit includes a resistor matching circuit to present a load of 150 to the amplifier and simultaneously provide 50 output impedance. The attenuation of this matching circuit is 15.45 dB. As the amplifier is configured for a voltage gain of 2, the overall gain in a 50 system is: 6 - 15.45 = -9.45 dB. The synchronized logic outputs are brought to a header for examination using oscilloscope probes. A set of jumper links allow the selection of operation with or without the built in color carrier filter. The selection is depicted on the board itself.
5 1 1 2
C1, C2, C3, C5, C6 C4 C7 C8, C9
100nF 1nF 10nF 10 F
ceramic X7R 50V 0805 ceramic NPO 50V 0805 ceramic X7R 50V 0805 tantalum elec 16V size C
Integrated circuits 1 1 U1 U2 ZXFV4583N16 - Zetex ZXFV4089N8 - Zetex
Miscellaneous 2 J1, J2 Socket BNC PCB straight flange e.g. Tyco B35N14H999X99 Terminal block 3-way IMO 20.501/3SB Header 8 way single row 2.54mm, Harwin M20-9990805 Header 8 way double row 2.54mm, Harwin M Test terminal, W. Hughes 200-207 Jumper Link, Harwin M7567-05
1
J3
-
1
PL1
-
1 3 2
PL2 TP1, TP2, TP3 LK1, LK2
-
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ZXFV4583
Figure 5: Evaluation circuit board schematic
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Figure 6: Evaluation circuit layout: Top side
Figure 7: Evaluation circuit layout: Bottom side (viewed through board)
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ZXFV4583
Figure 8: Evaluation circuit layout: Component layout
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PACKAGE OUTLINE
D
H
E
Pin1
c
A
Seating Plane b e
Millimeters DIM MIN A A1 b c D E e H h L 5.80 0.25 0.40 0 1.35 0.10 0.33 0.19 9.80 3.80 1.27BSC 6.20 0.50 1.27 8 MAX 1.75 MIN 0.053 0.004 0.013 0.008 0.386 0.150
A1
Inches MAX 0.069
0.25
0.51 0.25 10.00 4.00
0.010
0.020 0.010 0.394 0.157
0.050BSC 0.228 0.010 0.016 0 0.244 0.020 0.050 8
Conforms to JEDEC MS-012AC Iss C (SO16N) (c) Zetex plc 2003
Europe Zetex plc Fields New Road Chadderton Oldham, OL9 8NP United Kingdom Telephone (44) 161 622 4444 Fax: (44) 161 622 4446 hq@zetex.com Zetex GmbH Streitfeldstrae 19 D-81673 Munchen Germany Telefon: (49) 89 45 49 49 0 Fax: (49) 89 45 49 49 49 europe.sales@zetex.com Americas Zetex Inc 700 Veterans Memorial Hwy Hauppauge, NY 11788 USA Telephone: (1) 631 360 2222 Fax: (1) 631 360 8222 usa.sales@zetex.com Asia Pacific Zetex (Asia) Ltd 3701-04 Metroplaza Tower 1 Hing Fong Road Kwai Fong Hong Kong Telephone: (852) 26100 611 Fax: (852) 24250 494 asia.sales@zetex.com
These offices are supported by agents and distributors in major countries world-wide. This publication is issued to provide outline information only which (unless agreed by the Company in writing) may not be used, applied or reproduced for any purpose or form part of any order or contract or be regarded as a representation relating to the products or services concerned. The Company reserves the right to alter without notice the specification, design, price or conditions of supply of any product or service. For the latest product information, log on to
www.zetex.com ISSUE 3 - NOVEMBER 2003
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L

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