LM1881Video Sync SeparatorGeneral DescriptionThe LM1881 Video sync separator extracts timing informa-tion including composite and vertical sync, burst/back porchtiming, and odd/even field information from standard nega-tive going sync NTSC, PAL*and SECAM video signals withamplitude from 0.5V to 2V p-p. The integrated circuit is alsocapable of providing sync separation for non-standard,faster horizontal rate video signals. The vertical output isproduced on the rising edge of the first serration in thevertical sync period. A default vertical output is producedafter a time delay if the rising edge mentioned above doesnot occur within the externally set delay period, such asmight be the case for a non-standard video signal.Featuresn AC coupled composite input signaln>10 kΩ input resistancen<10 mA power supply drain currentn Composite sync and vertical outputsn Odd/even field outputn Burst gate/back porch outputn Horizontal scan rates to 150 kHzn Edge triggered vertical outputn Default triggered vertical output for non-standard videosignal (video games-home computers)Connection Diagram*PAL in this datasheet refers to European broadcast TV standard “Phase Alternating Line”, and not to Programmable Array Logic.LM1881NDS009150-1Order Number LM1881M or LM1881NSee NS Package Number M08A or N08EApril 2001LM1881 Video Sync Separator© 2001 National Semiconductor Corporation DS009150 www.national.comAbsolute Maximum Ratings (Note 1)If Military/Aerospace specified devices are required,please contact the National Semiconductor Sales Office/Distributors for availability and specifications.Supply Voltage 13.2VInput Voltage 3 VP-P(VCC= 5V)6VP-P(VCC≥ 8V)Output Sink Currents; Pins, 1, 3, 5 5 mAOutput Sink Current; Pin 7 2 mAPackage Dissipation (Note 2) 1100 mWOperating Temperature Range 0˚C–70˚CStorage Temperature Range −65˚C to +150˚CESD Susceptibility (Note 3) 2 kVSoldering InformationDual-In-Line Package (10 sec.) 260˚CSmall Outline PackageVapor Phase (60 sec.) 215˚CInfrared (15 sec.) 220˚CSee AN-450 “Surface Mounting Methods and their Effecton Product Reliability” for other methods of solderingsurface mount devices.Electrical CharacteristicsVCC= 5V; RSET= 680 kΩ;TA= 25˚C; Unless otherwise specifiedParameter Conditions TypTestedLimit (Note 4)DesignLimit (Note 5)Units(Limits)Supply Current Outputs atLogic 1VCC=5VVCC= 12V5.25.51012mAmaxmAmaxDC Input Voltage Pin 21.51.31.8VminVmaxInput Threshold Voltage (Note 6)705585mVminmVmaxInput Discharge Current Pin 2; VIN=2V11616µAminµAmaxInput Clamp Charge Current Pin 2; VIN= 1V 0.8 0.2 mAminRSETPin Reference Voltage Pin 6; (Note 7)1.221.101.35VminVmaxComposite Sync. & VerticalOutputsIOUT=40µA;Logic 1VCC=5VVCC= 12V4.5 4.011.0VminVminIOUT= 1.6 mALogic 1VCC=5VVCC= 12V3.6 2.410.0VminVminBurst Gate & Odd/EvenOutputsIOUT=40µA;Logic 1VCC=5VVCC= 12V4.5 4.011.0VminVminComposite Sync. Output IOUT= −1.6 mA; Logic 0; Pin 1 0.2 0.8 VmaxVertical Sync. Output IOUT= −1.6 mA; Logic 0; Pin 3 0.2 0.8 VmaxBurst Gate Output IOUT= −1.6 mA; Logic 0; Pin 5 0.2 0.8 VmaxOdd/Even Output IOUT= −1.6 mA; Logic 0; Pin 7 0.2 0.8 VmaxVertical Sync Width 230 190300µsminµsmaxBurst Gate Width 2.7 kΩ from Pin 5 to VCC42.54.7µsminµsmaxVertical Default Time (Note 8)653290µsminµsmaxNote 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device isfunctional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteedspecifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed testconditions.Note 2: For operation in ambient temperatures above 25˚C, the device must be derated based on a 150˚C maximum junction temperature and a package thermalresistance of 110˚C/W, junction to ambient.Note 3: ESD susceptibility test uses the “human body model, 100 pF discharged through a 1.5 kΩ resistor”.Note 4: Typicals are at TJ= 25˚C and represent the most likely parametric norm.Note 5: Tested Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).Note 6: Relative difference between the input clamp voltage and the minimum input voltage which produces a horizontal output pulse.Note 7: Careful attention should be made to prevent parasitic capacitance coupling from any output pin (Pins 1, 3, 5 and 7) to the RSETpin (Pin 6).Note 8: Delay time between the start of vertical sync (at input) and the vertical output pulse.LM1881www.national.com 2Typical Performance CharacteristicsApplication NotesThe LM1881 is designed to strip the synchronization signalsfrom composite video sources that are in, or similar to, theN.T.S.C. format. Input signals with positive polarity video(increasing signal voltage signifies increasing scene bright-ness) from 0.5V (p-p) to 2V (p-p) can be accommodated.The LM1881 operates from a single supply voltage between5V DC and 12V DC. The only required external componentsbesides a power supply decoupling capacitor at pin 8 and aset current decoupling capacitor at pin 6, are the compositeinput coupling capacitor at pin 2 and one resistor at pin 6 thatsets internal current levels. The resistor on pin 6 (i.e. Rset)allows the LM1881 to be adjusted for source signals with linescan frequencies differing from 15.734 kHz. Four major syncsignals are available from the I/C; composite sync includingboth horizontal and vertical scan timing information; a verti-cal sync pulse; a burst gate or back porch clamp pulse; andan odd/even output. The odd/even output level identifieswhich video field of an interlaced video source is present atthe input. The outputs from the LM1881 can be used togen-lock video camera/VTR signals with graphics sources,provide identification of video fields for memory storage,recover suppressed or contaminated sync signals, and pro-vide timing references for the extraction of coded or uncodeddata on specific video scan lines.To better understand the LM1881 timing information and thetype of signals that are used, refer toFigure 1(a-e)whichshows a portion of the composite video signal from the endof one field through the beginning of the next field.COMPOSITE SYNC OUTPUTThe composite sync output,Figure 1(b), is simply a repro-duction of the signal waveform below the composite videoblack level, with the video completely removed. This is ob-tained by