AD721JP

AD720 AD | Alldatasheet

Document overview

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Technical content

a FUNCTIONAL BLOCK DIAGRAM SYNC DECODER BURST C-SYNC 4FSC ENCD RED GREEN BLUE QUADRATURE DECODER DELAYED C-SYNC SC 90° SC 0° CLOCK AT 8FSC DC RESTORE AND C-SYNC INSERTION 5MHz 2-POLE LP POST- FILTER COMPOSITE OUTPUT* –0.572V TO 2V NTSC –0.6V TO 2V PAL LUMINANCE OUTPUT* –0.572V TO 1.43V NTSC –0.6V TO 1.4V PAL CHROMINANCE OUTPUT* 572mVp-p NTSC 600mVp-p PAL NTSC/ PAL C-SYNC DELAY –180° (PAL ONLY) RGB-TO-YUV ENCODING MATRIX BURST Y U V SC 90°/270° 5MHz 4-POLE LP PRE-FILTER 1.2MHz 4-POLE LPF 1.2MHz 4-POLE LPF SAMPLED- DATA DELAY LINE å 3.6MHz (NTSC) 4.4MHz (PAL) 3-POLE LPF å POWER AND GROUNDS +5V AGND DGND LOGIC ANALOG ANALOG ONLY ANALOG LOGIC +5V –5V *NOTE: THE LUMINANCE, COMPOSITE, AND CHROMINANCE OUTPUTS ARE AT TWICE NORMAL LEVELS FOR DRIVING 75W REVERSE-TERMINATED LINES. ASNC NTSC/ PAL BALANCED MODULATORS NTSC/ PAL ROUT 1.5Vp-p GOUT 1.5Vp-p BOUT 1.5Vp-p AD721 (ONLY) NTSC/ PAL AD720/AD721

FEATURES

Chrominance and Luminance (S-Video) Outputs No External Filters or Delay Lines Required Drives 75 Ω Reverse-Terminated Loads Compact 28-Pin PLCC Logic Selectable NTSC or PAL Encoding Modes Automatically Selects Proper Chrominance Filter Cutoff Frequency for Encoding Standard Logic Selectable Encode or Power-Down Mode (AD720 Only) Logic Selectable Encode or Bypass Mode (AD721 Only) Low Power: 200 mW typical

APPLICATIONS

RGB to NTSC or PAL Encoding Drive RGB Signals into 75 Ω Load (AD721 Only) PRODUCT DESCRIPTION The AD720 and AD721 RGB to NTSC/PAL Encoders convert red, green and blue color component signals into their corre- sponding luminance (baseband amplitude) and chrominance (subcarrier amplitude and phase) signals in accordance with either NTSC or PAL standards. These two outputs are also combined to provide a composite video output. All three out- puts are available separately at voltages of twice the standard signal levels as required for driving 75 Ω reverse terminated cables. The AD721 also features a bypass mode, in which the RGB inputs may bypass the encoder section of the IC via three gain-of-two amplifiers suitable for driving 75 Ω reverse termi- nated cables. The AD720 and AD721 provide a complete, fully calibrated function, requiring only termination resistors, bypass capacitors, a clock input at four times the subcarrier frequency, and a com- posite sync pulse. There are two control inputs: one input selects the TV standard (NTSC/PAL) and the other (ENCD) powers down most sections of the chip when the encoding func- tion is not in use (AD720) or activates the triple bypass buffer to drive the RGB signals when RGB encoding is not required (AD721). All logical inputs are CMOS compatible. The chip operates from ± 5 V supplies. (continued on page 5) RGB to NTSC/PAL Encoders Tel: 617/329-4700 Fax: 617/326-8703 REV. 0 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

REV. 0–2– Parameter Conditions Min Typ Max Unit SIGNAL INPUTS (RDIN, GRIN, BLIN) Input Amplitude NTSC 714 mV PAL 700 mV Input Resistances 1 RDIN with Respect to AGND 2.3 k Ω GRIN with Respect to AGND 4.2 k Ω BLIN with Respect to AGND 4.2 k Ω Input Capacitance 5p F LOGIC INPUTS (C-SYNC, 4FSC, ENCD, NTSC) Logic LO Input Voltage 1 V Logic HI Input Voltage 4 V Logic LO Input Current (DC) <1 µA Logic HI Input Current (DC) <1 µA BYPASS AMPLIFIERS (AD721 Only) Gain Error Nominal Gain of ×22 –5 +5 % Small Signal –3 dB Bandwidth 100 MHz Output Offset Voltage (Active State) –50 +50 mV Output Voltage (Inactive State) –50 +50 mV VIDEO OUTPUTS3 (LUMA, CRMA, CMPS) Luminance (LUMA) Output Bandwidth 5 MHz Gain Error –5 ± 1 +5 % Linearity ± 0.1 % Sync Level NTSC 252 286 320 mV PAL 300 mV Chrominance (CRMA) Output Bandwidth NTSC 3.6 MHz PAL 4.4 MHz Color Burst Amplitude NTSC 257 286 315 mV p-p PAL 300 mV p-p Absolute Gain Error –15 ± 5 +15 % Absolute Phase Error ± 3 Degrees Chroma/Luma Time Alignment 4 NTSC –170 ns Composite Output Absolute Gain Error –5 ± 1 +5 % Differential Gain With Respect to Chroma Channel 0.1 % Differential Phase With Respect to Chroma Channel 0.1 Degrees Output Offset Voltage Chroma, Luma, or Composite Outputs 50 100 mV Chroma Feedthrough Monochrome Input 20 55 mV p-p POWER SUPPLIES (APOS, DPOS, VNEG) Recommended Supply Range Dual Supply ± 4.75 ± 5.25 V Full Output Current 5 –5 V Supply 35 mA +5 V Supply 67 mA Zero Signal Quiescent Current –5 V Supply 10 20 35 mA +5 V Supply 10 20 35 mA Bypass Mode Quiescent Current –5 V Supply 14 20 mA (AD721 Only) +5 V Supply 14 20 mA AD720/AD721–SPECIFICATIONS NOTES 1Input scaling resistors provide best scaling accuracy when source resistance is 37.5 Ω (75 Ω reverse-terminated input). 2Required for driving a 75 Ω double reverse terminated load. 3All outputs are measured at a reverse-terminated load; voltages at IC pins are twice those specified here. 4This is a predistortion (per FCC specifications) that compensates for the chroma/luma delay in the low-pass filter that separat es the luminance and chrominance signals in a television receiver. 5CRMA, LUMA, and CMPS outputs are all connected to 75 Ω reverse-terminated loads; full-white signal for entire field. Specifications shown in boldface are tested on all production units at final electrical test. Results from those tests are used to calculate outgoing quality l evels. All min and max specifications are guaranteed, although only those shown in boldface are tested on all production units. Specifications subject to change without notice. (TA = +25°C and supplies = ±5 V unless otherwise noted)

REV. 0 –3– PIN DESCRIPTIONS Pin Mnemonic* Description* 1 (NC) GOUT (No Connection) Green Bypass Buffer 2 (NC) APOS (No Connection) Analog Positive Supply; +5 V ± 5% 3 (NC) ROUT (No Connection) Red Bypass Buffer

4 AGND Analog Ground Connection

5 ENCD A Logical High Enables the NTSC/PAL Encode

Mode (A Logical Low Powers Down the Chip) A Logical Low Enables the RGB Bypass Mode

6 RDIN Red Component Video Input

7 AGND Analog Ground Connection

8 GRIN Green Component Video Input

9 AGND Analog Ground Connection

10 BLIN Blue Component Video Input

11 STND A Logical High Input Selects NTSC Encoding

A Logical Low Input Selects PAL Encoding CMOS Logic Levels

12 AGND Analog Ground Connection

13 CRMA Chrominance Output; Subcarrier Only**

572 mV Peak-to-Peak for NTSC 600 mV Peak-to-Peak for PAL

14 APOS Analog Positive Supply; +5 V ± 5%

15 CMPS Composite Video Output**

–572 mV to 2 V for NTSC –600 mV to 2 V for PAL

16 APOS Analog Positive Supply; +5 V ± 5%

17 LUMA Luminance Plus SYNC Output**

–572 mV to 1.43 V for NTSC –600 mV to 1.4 V for PAL

18 VNEG System Negative Supply; –5 V ± 5%

19 DGND Digital Ground Connection

20 4FSC Clock Input at Four Times the Subcarrier Frequency 14.318 180 MHz for NTSC 17.734 480 MHz for PAL CMOS Logic Levels

21 DPOS Digital Positive Supply; +5 V ± 5%

22 ASNC A Logical High Input Resets the Subcarrier Phase

A Logical Low Input Resets the Subcarrier Phase Every Fourth Frame CMOS Logic Levels

23 DPOS Digital Positive Supply; +5 V ± 5%

24 SYNC Input for Composite Television

25 DGND Digital Ground Connections (One of Two)

26 VNEG System Negative Supply; –5 V ± 5%

27 (NC) BOUT (No Connection) Blue Bypass Buffer

28 APOS Analog Positive Supply; +5 V ± 5%

*( ) pertain only to AD720. **The luminance, chrominance, and composite outputs are at twice normal levels for driving 75 Ω reverse-terminated lines. ORDERING GUIDE Temperature Package Model Range Package Option AD720JP 0 °C to +70°C 28-Pin PLCC P-28A AD721JP 0 °C to +70°C 28-Pin PLCC P-28A PIN CONNECTIONS 28-Lead Plastic Leaded Chip Carrier (PLCC) Package P-28A AD720/AD721 RGB TO NTSC/PAL ENCODER 28 27 261234 12 13 14 15 16 17 18 DGND SYNC DPOS ASNC DPOS 4FSC DGND ENCD RDIN AGND GRIN AGND BLIN STND AGND ROUT (NC) APOS (NC) GOUT (NC) APOS BOUT (NC) VNEG AGND CRMA APOS CMPS LUMA VNEG APOS NOTE: CONNECTIONS IN ( ) PERTAIN ONLY TO AD720 ABSOLUTE MAXIMUM RATINGS* NOTE *Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only, and functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended rating conditions for extended periods may affect device reliability. Thermal characteristics: 28-pin plastic package: θ JA = 100°C. WARNING! ESD SENSITIVE DEVICE CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the AD720/AD721 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.

Figure 1. AD720/AD721 Evaluation Setup Figure 2. Composite Output Differential Phase and Gain,

525 LINE NTSC; NO FILTERING

Figure 3. Modulated Pulse and Bar, NTSC Figure 4. 100% Color Bars, NTSC Figure 5. Multipulse, NTSC

39.4 IRE

39.2 IRE

Figure 6. Horizontal Timing, NTSC Figure 7. Horizontal Timing, PAL

chip carrier for the 0°C to +70°C commercial temperature range. burst signal is inserted into the Y channel in the encoding matrix. troduced by the filters in the decoding process. DRIVING 75W REVERSE-TERMINATED LINES. Figure 8. AD720/AD721 Functional Block Diagram

of a gain block to properly drive the monitor.

4 X SUBCARRIER INPUT

Figure 9. AD720 Application Figure 10. AD721 Application

REV. 0–8– AD720/AD721 OUTLINE DIMENSIONS Dimensions shown in inches and (mm). PRINTED IN U.S.A. C1932–7.5–7/94 28-Lead Plastic Leaded Chip Carrier (PLCC) Package P-28A 0.048 (1.21) 0.042 (1.07) 0.456 (11.58) 0.450 (11.43) SQ 0.495 (12.57) 0.485 (12.32)SQ 0.048 (1.21) 0.042 (1.07) 0.050 (1.27) BSC 26 4 TOP VIEW PIN 1 IDENTIFIER 0.020 (0.50) R 0.032 (0.81) 0.026 (0.66) 0.021 (0.53) 0.013 (0.33) 0.056 (1.42) 0.042 (1.07) 0.025 (0.63) 0.015 (0.38) 0.180 (4.57) 0.165 (4.19) 0.430 (10.92) 0.390 (9.91) 0.110 (2.79) 0.085 (2.16) 0.040 (1.01) 0.025 (0.64)