Analog Devices AD725AR-REEL7, AD725AR-REEL, AD725AR, AD725-EB Datasheet

a

Low Cost RGB to NTSC/PAL Encoder

with Luma Trap Port

AD725

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: [phone] World Wide Web Site: http://www.analog.com

Fax: [phone] © Analog Devices, Inc., 1997

FEATURES

Composite Video Output: Both NTSC and PAL

Chrominance and Luminance (S-Video) Outputs

Luma Trap Port to Eliminate Cross Color Artifacts

TTL Logic Levels

Integrated Delay Line and Auto-Tuned Filters

Drives 75 V Reverse-Terminated Loads

Low Power +5 V Operation

Power-Down to <1 mA

Very Low Cost

APPLICATIONS

RGB/VGA to NTSC/PAL Encoding

Personal Computers/Network Computers

Video Games

Video Conference Cameras

Digital Still Cameras

PRODUCT DESCRIPTION

The AD725 is a very low cost general purpose RGB to NTSC/

PAL encoder that converts red, green and blue color compo-

nent signals into their corresponding luminance (baseband

amplitude) and chrominance (subcarrier amplitude and phase)

signals in accordance with either NTSC or PAL standards.

These two outputs are also combined on-chip to provide a

composite video output. All three outputs are available sepa-

rately at voltages of twice the standard signal levels as re-

quired for driving 75 Ω, reverse-terminated cables.

The AD725 features a luminance trap (YTRAP) pin that pro-

vides a means of reducing cross color generated by subcarrier

frequency components found in the luminance signal. For por-

table or other power-sensitive applications, the device can be

powered down to less than 1 µA of current consumption. All

logic levels are TTL compatible thus supporting the logic re-

quirements of 3 V CMOS systems.

The AD725 is packaged in a low cost 16-lead SOIC and oper-

ates from a +5 V supply.

FUNCTIONAL BLOCK DIAGRAM

4FSC

NTSC/PAL

HSYNC

VSYNC

BURST

NTSC/PAL

FSC 90

8

C

FSC 0

8

C

4FSC

FSC 90

8

C/270

8

C

CSYNC

CSYNC

RED

GREEN

BLUE

CSYNC

Y

U

V

BALANCED

MODULATORS

NTSC/PAL

X2

X2

X2

LUMINANCE

OUTPUT

COMPOSITE

OUTPUT

CHROMINANCE

OUTPUT

CLOCK

AT 8FSC

SYNC

SEPARATOR

QUADRATURE

+4

DECODER

BURST

3-POLE

LP PRE-

FILTER

4-POLE

LPF

4-POLE

LPF

6

180

8

C

(PAL ONLY)

RGB-TO-YUV

ENCODING

MATRIX

SAMPLED-

DATA

DELAY LINE

4-POLE

LPF

2-POLE

LP POST-

FILTER

LUMINANCE

TRAP

4FSC CLOCK

V

CLAMP

U

CLAMP

DC

CLAMP

DC

CLAMP

DC

CLAMP

XNOR

S

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.

AD725–SPECIFICA TIONS

REV. 0

–2–

(Unless otherwise noted, V

S

= +5, T

A

= +258C, using 4FSC synchronous clock. All loads are

150 V 6 5% at the IC pins. Outputs are measured at the 75 V reverse terminated load.)

Parameter Conditions Min Typ Max Units

SIGNAL INPUTS (RIN, GIN, BIN)

Input Amplitude Full Scale 714 mV p-p

Black Level

1

0.8 V

Input Resistance

2

RIN, GIN, BIN 1 MΩ

Input Capacitance 5pF

LOGIC INPUTS (HSYNC, VSYNC, 4FSC, CE, STND) TTL Logic Levels

Logic Low Input Voltage 1V

Logic High Input Voltage 2V

Logic Low Input Current (DC) 1 µA

Logic High Input Current (DC) 1 µA

VIDEO OUTPUTS

3

Luminance (LUMA)

Bandwidth, –3 dB NTSC 4.4 MHz

PAL 5.2 MHz

Gain Error –7 –2 +7 %

Nonlinearity max p-p 0.3 %

Sync Level NTSC 252 279 310 mV

PAL 264 291 325 mV

DC Black Level 1.3 V

Luminance Trap (YTRAP)

Output Resistance 1.0 kΩ

DC Black Level 1.0 V

Chrominance (CRMA)

Bandwidth, –3 dB NTSC 1.2 MHz

PAL 1.5 MHz

Color Burst Amplitude NTSC 206 255 305 mV p-p

PAL 221 291 362 mV p-p

Color Burst Width NTSC 2.51 µs

PAL 2.28 µs

Chroma Level Error

4

–4 %

Chroma Phase Error

5

±3 Degrees

DC Black Level 2.0 V

Chroma Feedthrough R, G, B = 0 15 40 mV p-p

Composite (COMP)

Absolute Gain Error With Respect to Luma –5 –1 +3 %

Differential Gain With Respect to Chroma 0.5 %

Differential Phase With Respect to Chroma 1.5 Degrees

DC Black Level 1.4 V

Chroma/Luma Time Alignment S-Video 20 ns

POWER SUPPLIES

Recommended Supply Range Single Supply +4.75 +5.25 V

Quiescent Current—Encode Mode 30 36 mA

Quiescent Current—Power Down <1 µA

NOTES

1

R, G, and B signals are inputted via an external ac coupling capacitor.

2

Except during dc restore period (back porch clamp).

3

All outputs measured at a 75 Ω reverse-terminated load; ac voltages at the IC output pins are twice those specified here.

4

Difference between ideal and actual color bar subcarrier amplitudes.

5

Difference between ideal and actual color bar subcarrier phases.

Specifications are subject to change without notice.

AD725

REV. 0

–3–

ORDERING GUIDE

Temperature Package Package

Model Range Description Option

AD725AR –40°C to +85°C 16-Lead SOIC R-16

AD725AR-Reel –40°C to +85°C 16-Lead SOIC R-16

AD725AR-Reel7 –40°C to +85°C 16-Lead SOIC R-16

AD725-EB Evaluation Board

ABSOLUTE MAXIMUM RATINGS*

Supply Voltage, APOS to AGND . . . . . . . . . . . . . . . . . . +6 V

Supply Voltage, DPOS to DGND . . . . . . . . . . . . . . . . . . +6 V

AGND to DGND . . . . . . . . . . . . . . . . . . . . . –0.3 V to +0.3 V

Inputs . . . . . . . . . . . . . . . . . . . DGND – 0.3 to DPOS + 0.3 V

Internal Power Dissipation . . . . . . . . . . . . . . . . . . . . . .800 mW

Operating Temperature Range . . . . . . . . . . . .–40°C to +85°C

Storage Temperature Range . . . . . . . . . . . . .–65°C to +125°C

Lead Temperature Range (Soldering 30sec) . . . . . . . . +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 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 periods may affect device reliability.

Thermal Characteristics: 16-Pin SOIC Package: θ

JA

= 100°C/W.

PIN CONFIGURATION

16-Lead Wide Body (SOIC)

(R-16)

AGND

CE

RIN

GIN

4FSC

APOS

BIN

STND

HSYNC

VSYNC

YTRAP

LUMA

COMP

DPOS

DGND

CRMA

1

2

16

15

5

6

7

12

11

10

3

4

14

13

89

TOP VIEW

(Not to Scale)

AD725

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 AD725 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.

WARNING!

ESD SENSITIVE DEVICE

REV. 0

–4–

AD725

PIN DESCRIPTIONS

Pin Mnemonic Description Equivalent Circuit

1 STND Encoding Standard Pin. A Logic HIGH input selects NTSC encoding. Circuit A

A Logic LOW input selects PAL encoding.

TTL Logic Levels.

2 AGND Analog Ground Connection.

3 4FSC 4FSC Clock Input. Circuit A

For NTSC: 14.318 180 MHz.

For PAL: 17.734 475 MHz.

TTL Logic Levels.

4 APOS Analog Positive Supply (+5 V ± 5%).

5 CE Chip Enable. A Logic HIGH input enables the encode function. Circuit A

A Logic LOW input powers down chip when not in use.

TTL Logic Levels.

6 RIN Red Component Video Input. Circuit B

0 mV to 714 mV AC-Coupled.

7 GIN Green Component Video Input. Circuit B

0 mV to 714 mV AC-Coupled.

8 BIN Blue Component Video Input. Circuit B

0 mV to 714 mV AC-Coupled.

9 CRMA Chrominance Output.* Circuit C

Approximately 1.8 V peak-to-peak for both NTSC and PAL.

10 COMP Composite Video Output.* Circuit C

Approximately 2.5 V peak-to-peak for both NTSC and PAL.

11 LUMA Luminance plus CSYNC Output.* Circuit C

Approximately 2 V peak-to-peak for both NTSC and PAL.

12 YTRAP Luminance Trap Filter Tap. Attach L-C resonant network to reduce cross-color artifacts. Circuit D

13 DGND Digital Ground Connection.

14 DPOS Digital Positive Supply (+5 V ± 5%).

15 VSYNC Vertical Sync Signal (if using external CSYNC set at > +2 V). TTL Logic Levels. Circuit A

16 HSYNC Horizontal Sync Signal (or CSYNC signal). TTL Logic Levels. Circuit A

*The Luminance, Chrominance and Composite Outputs are at twice normal levels for driving 75 Ω reverse-terminated lines.

7

V

CLAMP

6

8

DPOS

DGND

3

1

5

15

16

DPOS

DGND

10

9

11

APOS

AGND

DGND

DPOS

APOS

AGND

DGND

DPOS

12

1kV

Circuit A Circuit B Circuit C Circuit D

Figure 1. Equivalent Circuits

REV. 0

–5–

T ypical Characteristics–AD725

IRE

µs

1.0

0.5

–0.5

06010 20 30 40 50

0.0

APL = 50.8%

525 LINE NTSC NO FILTERING

SLOW CLAMP TO 0.00V @ 6.63

m

s

100

50

0

–50

VOLTS

Figure 3. 100% Color Bars, NTSC

Figure 4. 100% Color Bars on Vector Scope, NTSC

RGB

3

75V

75V

COMPOSITE

VIDEO

COMPOSITE

SYNC

FSC

GENLOCK

TEKTRONIX

TG2000

SIGNAL

GENERATION

PLATFORM

AD725

RGB TO

NTSC/PAL

ENCODER

TEKTRONIX

VM700A

WAVEFORM

MONITOR

SONY

MONITOR

MODEL

PVM-1354Q

+5V

4FSC

HP3314A

3 4 PLL

FSC

(3.579545MHz

OR

4.433618MHz)

OSCILLATOR

Figure 2. Evaluation Setup

ms

1.0

0.5

–0.5

06010 20 30 40 50

0.0

VOLTS

APL = 50.6%

625 LINE PAL NO FILTERING

SLOW CLAMP TO 0.00V @ 6.72

m

s

Figure 5. 100% Color Bars, PAL

Figure 6. 100% Color Bars on Vector Scope, PAL

REV. 0

–6–

AD725–Typical Characteristics

APL = 46.6%

525 LINE NTSC NO FILTERING

SLOW CLAMP TO 0.00V

@ 6.63ms

ms

06010 20 30 40 50

IRE

1.0

0.5

–0.5

0.0

100

50

0

–50

VOLTS

Figure 7. Modulated Pulse and Bar, NTSC

200mV 1

m

s

Figure 8. Zoom on Modulated Pulse, NTSC

ms

1.0

0.5

–0.5

06010 20 30 40 50

0.0

APL = 33.5%

625 LINE PAL NO FILTERING

SLOW CLAMP TO 0.00V

@ 6.72 ms

VOLTS

Figure 9. Modulated Pulse and Bar, PAL

200mV 1

m

s

Figure 10. Zoom on Modulated Pulse, PAL