2.7 V to 5.5 V RGB-to-NTSC/PAL Encoder with a Load Detect and Input Termination Switch AD723 FEATURES or combined for composite video (CV). All outputs are avail- Low Cost, Fully Integrated Solution for NTSC/PAL able separately and optimized for driving 75 loads. Active Composite and Y/C (S-Video) Outputs termination is used for lower power consumption. Current Output Drives 75 Loads A smart load detect feature powers down unused outputs and DC-Coupled: Supports TV Load Detect can be used to monitor the continuing presence or absence of No Large AC-Coupling Capacitors at Output an external TV. This enables plug-and-play operation. In addition, Self-Power-Down of Unloaded Output Drivers a logic controlled triple switch at the input solves the applica- Triple Switch to Enable RGB Termination tions problem of differing load conditions when an RGB monitor Integrated Delay Line and Auto-Tuned Filters is disconnected. When an RGB monitor is not present, the R, Y-Trap to Eliminate Cross Color Artifacts G, and B terminations are enabled by the user. This solution 3 V Supply Operation: Low Power ensures no loss of video bandwidth when the RGB monitor is < 100 mW: Composite Active (Typical) in operation. < 150 mW: S-Video Active (Typical) <1 A: Power-Down Current In PC applications, flicker filter support is provided by the graphics controller, which has direct access to memory. Under- APPLICATIONS scan compensation, necessary for uses other than video or TV Out for Personal Computers/Laptops DVD, is supported through choice of RGB output clocks and Digital Cameras Set-Top Boxes sync intervals. Video Games An optional luminance trap (YTRAP) provides a means of Internet Appliances reducing cross color artifacts due to subcarrier frequency infor- PRODUCT DESCRIPTION mation in the Y signal. The AD723 is a low cost RGB-to-NTSC/PAL encoder that The AD723 is available in a 28-lead TSSOP package and is converts analog red, green, and blue color component signals capable of operation from supplies of 2.7 V to 5.5 V. into their corresponding luminance and chrominance signals for display on an NTSC or PAL television. Luminance (Y) and Chrominance (C) signals are available individually for S-video, FUNCTIONAL BLOCK DIAGRAM CURRENT OUTPUT DRIVERS WITH SMART LOAD DETECT 8FSC CLK TRIPLE INPUT TERMINATION LUMINANCE RIN Y Y DC 4-POLE LUMA 4-POLE CLAMP LPF LPF DELAY LINE RT LUMA Y TRAP TRAP GND CSYNC COMPOSITE CV RGB-TO-YUV ENCODING U GIN DC 4-POLE MATRIX CLAMP LPF GT CHROMINANCE BALANCED GND MODULATORS 4-POLE C BURST LPF V BIN DC 4-POLE CLAMP LPF BT YSET GND SIN COS BURST GAIN SET CSET TERM RESISTORS AD723 CVSET QUADRATURE FSC 4FSC DECODER HSYNC BURST SYNC VSYNC SEPARATOR CSYNC STND CE TV DETECT REV. 0 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. use, nor for any infringements of patents or other rights of third parties Tel: 781/329-4700 World Wide Web Site: (V = 3, T = 25 C, using 4FSC synchronous clock unless otherwise noted. Signal AD723SPECIFICATIONS S A inputs terminated with 75 . Outputs configured in active termination mode, 75 external load.) Parameter Conditions Min Typ Max Unit SIGNAL INPUTS (RIN, GIN, BIN) Input Amplitude Full-Scale 714 mV p-p Clamp Level 400 mV Input Resistance RIN, GIN, BIN 1 M Input Capacitance 5pF TERMINATION SWITCH CHARACTERISTICS (RT, GT, BT) Input Capacitance VIN = 0 V 6 pF Switch On Resistance VIN = 0 V 5.2 LOGIC INPUTS (STND, SA, CE, TERM, SYNC, 4FSC) Logic LO Input Voltage 1V Logic HI Input Voltage 2 V Logic LO Input Current (DC) 0.015 0.70 A Logic HI Input Current (DC) 0.020 0.70 A VIDEO OUTPUTS Luminance (Y) 3 dB Bandwidth, NTSC Mode NTSC 4.7 MHz PAL 6.1 MHz Gain Error Direct Input Termination 6.25 2.5 +1.5 % Switch Input Termination 0.7 % Gain Nonlinearity 0.3 % Sync Amplitude NTSC 218 262 362 mV PAL 230 277 385 mV DC Black Level NTSC 450 mV PAL 450 mV Chrominance (C) Burst Amplitude NTSC 185 250 315 mV p-p PAL 190 251 320 mV p-p 1 Chroma Level Error Switch Input Termination 4 % 2 Chroma Phase Error 3 Degree Color Burst Width NTSC 2.51 s PAL 2.26 s Chroma/Luma Time Alignment 19 ns Chroma Feedthrough RGB = 0 10.5 40 mV p-p DC Black Level NTSC 661 mV PAL 608 mV Composite (CV) Gain Error Direct Input Termination 6.8 2.4 +2.5 % Switch Input Termination 0.75 % Gain Error wrt LUMA Direct Input Termination 0.14 % Differential Gain Error wrt CRMA 0.9 % Differential Phase Error wrt CRMA 0.95 Degree DC Black Level NTSC 456 mV PAL 440 mV Luminance Trap (YTRAP) Output Resistance 1.4 k LOGIC OUTPUT (TVDET) LO Output Voltage 0.02 V HI Output Voltage 2.98 V POWER SUPPLIES Operating Voltage Range Single Supply 2.7 5.5 V Current Consumption Quiescent No External Loads Present 16 19 mA 3 Composite Output Connected 75 Load, Active Termination, 30 39 mA S-Video Inactive 3 S-Video Output Connected 75 Load, Active Termination, 41 49 mA Composite Output Inactive Power-Down Current 0.09 0.7 A NOTES 1 Difference between ideal and actual color-bar subcarrier amplitudes. 2 Difference between ideal and actual color-bar subcarrier phase. 3 Current consumption is larger in standard termination mode. Current values shown for 50% average picture level. Larger current consumption possible for other levels. Specifications subject to change without notice. 2 REV. 0