a Low Cost RGB to NTSC/PAL Encoder with Luma …

1 ALow Cost RGB to NTSC/PAL Encoderwith Luma Trap PortAD725 One Technology Way, Box 9106, Norwood, MA 02062-9106, : 781/329-4700 World Wide Web Site: : 781/326-8703 analog Devices, Inc., 1997 FEATURESC omposite Video Output: Both ntsc and PALC hrominance and Luminance (S-Video) OutputsLuma Trap Port to Eliminate Cross Color ArtifactsTTL Logic LevelsIntegrated Delay Line and Auto-Tuned FiltersDrives 75 V Reverse-Terminated LoadsLow Power +5 V OperationPower-Down to <1 mAVery Low CostAPPLICATIONSRGB/VGA to NTSC/PAL EncodingPersonal Computers/Network ComputersVideo GamesVideo Conference CamerasDigital Still CamerasPRODUCT DESCRIPTIONThe AD725 is a very low cost general purpose RGB to NTSC/PAL Encoder that converts red.

2 Green and blue color compo-nent signals into their corresponding luminance (basebandamplitude) and chrominance (subcarrier amplitude and phase)signals in accordance with either ntsc or PAL two outputs are also combined on-chip to provide acomposite video output. All three outputs are available sepa-rately at voltages of twice the standard signal levels as re-quired for driving 75 , reverse-terminated AD725 features a luminance trap (YTRAP) pin that pro-vides a means of reducing cross color generated by subcarrierfrequency components found in the luminance signal.

3 For por-table or other power-sensitive applications, the device can bepowered down to less than 1 A of current consumption. Alllogic levels are TTL compatible thus supporting the logic re-quirements of 3 V CMOS AD725 is packaged in a low cost 16-lead SOIC and oper-ates from a +5 V BLOCK DIAGRAM4 FSCNTSC/PALHSYNCVSYNCBURSTNTSC/PALFSC 908 CFSC 08C4 FSCFSC 908C/2708 CCSYNCCSYNCREDGREENBLUECSYNCYUVBALANCEDM ODULATORSNTSC/PALX2X2X2 LUMINANCEOUTPUTCOMPOSITEOUTPUTCHROMINANC EOUTPUTCLOCKAT 8 FSCSYNCSEPARATORQUADRATURE+4 DECODERBURST3-POLELP PRE-FILTER4-POLELPF4-POLELPF61808C(PAL ONLY)

4 RGB-TO-YUVENCODINGMATRIXSAMPLED-DATADELA Y LINE4-POLELPF2-POLELP POST-FILTERLUMINANCETRAP4 FSC CLOCKVCLAMPUCLAMPDCCLAMPDCCLAMPDCCLAMPXN ORSREV. 0 Information furnished by analog Devices is believed to be accurate andreliable. However, no responsibility is assumed by analog Devices for itsuse, nor for any infringements of patents or other rights of third partieswhich may result from its use. No license is granted by implication orotherwise under any patent or patent rights of analog SPECIFICATIONSREV. 0 2 (Unless otherwise noted, VS = +5, TA = +258C, using 4 FSC synchronous clock.)

5 All loads are150 V 6 5% at the IC pins. Outputs are measured at the 75 V reverse terminated load.)ParameterConditionsMinTypMaxUnitsS IGNAL INPUTS (RIN, GIN, BIN)Input AmplitudeFull Scale714mV p-pBlack Resistance2 RIN, GIN, BIN1M Input Capacitance5pFLOGIC INPUTS (HSYNC, VSYNC, 4 FSC, CE, STND)TTL Logic LevelsLogic Low Input Voltage1 VLogic High Input Voltage2 VLogic Low Input Current (DC)1 ALogic High Input Current (DC)1 AVIDEO OUTPUTS3 Luminance (LUMA)Bandwidth, 3 Error 7 2+7%Nonlinearitymax LevelNTSC252279310mVPAL264291325mVDC Black Trap (YTRAP)Output DC Black (CRMA)

6 Bandwidth, 3 Burst AmplitudeNTSC206255305mV p-pPAL221291362mV p-pColor Burst sChroma Level Error4 4%Chroma Phase Error5 3 DegreesDC Black FeedthroughR, G, B = 01540mV p-pComposite (COMP)Absolute Gain ErrorWith Respect to Luma 5 1+3%Differential GainWith Respect to PhaseWith Respect to Black Time AlignmentS-Video20nsPOWER SUPPLIESR ecommended Supply RangeSingle Supply+ + VQuiescent Current Encode Mode3036mAQuiescent Current Power Down<1 ANOTES1R, G, and B signals are inputted via an external ac coupling during dc restore period (back porch clamp).

7 3 All outputs measured at a 75 reverse-terminated load; ac voltages at the IC output pins are twice those specified between ideal and actual color bar subcarrier between ideal and actual color bar subcarrier are subject to change without 0 3 ORDERING GUIDET emperaturePackagePackageModelRangeDescri ptionOptionAD725AR 40 C to +85 C16-Lead SOICR-16AD725AR-Reel 40 C to +85 C16-Lead SOICR-16AD725AR-Reel7 40 C to +85 C16-Lead SOICR-16AD725-EBEvaluation BoardABSOLUTE MAXIMUM RATINGS*Supply Voltage, APOS to AGND.

8 +6 VSupply Voltage, DPOS to DGND .. +6 VAGND to DGND .. V to + VInputs .. DGND to DPOS + VInternal Power Dissipation .. 800 mWOperating Temperature Range .. 40 C to +85 CStorage Temperature Range .. 65 C to +125 CLead Temperature Range (Soldering 30 sec) .. +230 C*Stresses above those listed under Absolute Maximum Ratings may cause perma-nent damage to the device. This is a stress rating only; functional operation of thedevice at these or any other conditions above those indicated in the operationalsection of this specification is not implied.

9 Exposure to absolute maximum ratingconditions for extended periods may affect device Characteristics: 16-Pin SOIC Package: JA = 100 CONFIGURATION16-Lead Wide Body (SOIC)(R-16)AGNDCERINGIN4 FSCAPOSBINSTNDHSYNCVSYNCYTRAPLUMACOMPDPO SDGNDCRMA12161556712111034141389 TOP VIEW(Not to Scale)AD725 CAUTIONESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readilyaccumulate on the human body and test equipment and can discharge without the AD725 features proprietary ESD protection circuitry, permanent damage mayoccur on devices subjected to high energy electrostatic discharges.

10 Therefore, proper ESDprecautions are recommended to avoid performance degradation or loss of !ESD SENSITIVE DEVICEREV. 0 4 AD725 PIN DESCRIPTIONSPinMnemonicDescriptionEquiva lent Circuit1 STNDE ncoding Standard Pin. A Logic HIGH input selects ntsc AA Logic LOW input selects PAL Logic Ground Clock AFor ntsc : 180 PAL: 475 Logic Positive Supply (+5 V 5%).5 CEChip Enable. A Logic HIGH input enables the encode AA Logic LOW input powers down chip when not in Logic Component Video B0 mV to 714 mV Component Video B0 mV to 714 mV Component Video B0 mV to 714 mV Output.