AD723ARU-EVAL
REV. 0
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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.
a
AD723
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 World Wide Web Site: http://www.analog.com
Fax: 781/326-8703 © Analog Devices, Inc., 2000
2.7 V to 5.5 V RGB-to-NTSC/PAL Encoder with
Load Detect and Input Termination Switch
FUNCTIONAL BLOCK DIAGRAM
4-POLE
LPF
CSYNC
Y
DC
CLAMP
4-POLE
LPF
LUMINANCE
8FSC CLK
LUMA
DELAY LINE
RIN
COMPOSITE
LUMA
TRAP
GND
TRIPLE INPUT
TERMINATION
CURRENT OUTPUT DRIVERS
WITH SMART LOAD DETECT
Y
Y TRAP
CV
C
RT
4-POLE
LPF
4-POLE
LPF
BURST
BURST
U
V
DC
CLAMP
4FSC
HSYNC
VSYNC
BURST
STND
CSYNC
GIN
BIN
DC
CLAMP
BALANCED
MODULATORS
CHROMINANCE
SYNC
SEPARATOR
RGB-TO-YUV
ENCODING
MATRIX
4-POLE
LPF
QUADRATURE
DECODER
GND
GND
FSC
SIN COS
YSET
CSET
CVSET
GAIN SET
RESISTORS
TV DETECTCE
AD723
TERM
GT
BT
FEATURES
Low Cost, Fully Integrated Solution for NTSC/PAL
Composite and Y/C (S-Video) Outputs
Current Output Drives 75 ⍀ Loads
DC-Coupled: Supports TV Load Detect
No Large AC-Coupling Capacitors at Output
Self-Power-Down of Unloaded Output Drivers
Triple Switch to Enable RGB Termination
Integrated Delay Line and Auto-Tuned Filters
Y-Trap to Eliminate Cross Color Artifacts
3 V Supply Operation: Low Power
< 100 mW: Composite Active (Typical)
< 150 mW: S-Video Active (Typical)
<1 A: Power-Down Current
APPLICATIONS
TV Out for Personal Computers/Laptops
Digital Cameras
Set-Top Boxes
Video Games
Internet Appliances
PRODUCT DESCRIPTION
The AD723 is a low cost RGB-to-NTSC/PAL encoder that
converts analog red, green, and blue color component signals
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,
or combined for composite video (CV). All outputs are avail-
able separately and optimized for driving 75 Ω loads. Active
termination is used for lower power consumption.
A smart load detect feature powers down unused outputs and
can be used to monitor the continuing presence or absence of
an external TV. This enables plug-and-play operation. In addition,
a logic controlled triple switch at the input solves the applica-
tions problem of differing load conditions when an RGB monitor
is disconnected. When an RGB monitor is not present, the R,
G, and B terminations are enabled by the user. This solution
ensures no loss of video bandwidth when the RGB monitor is
in operation.
In PC applications, flicker filter support is provided by the
graphics controller, which has direct access to memory. Under-
scan compensation, necessary for uses other than video or
DVD, is supported through choice of RGB output clocks and
sync intervals.
An optional luminance trap (YTRAP) provides a means of
reducing cross color artifacts due to subcarrier frequency infor-
mation in the Y signal.
The AD723 is available in a 28-lead TSSOP package and is
capable of operation from supplies of 2.7 V to 5.5 V.
REV. 0
–2–
AD723–SPECIFICATIONS
(V
S
= 3, T
A
= 25ⴗC, using 4FSC synchronous clock unless otherwise noted. Signal
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 MΩ
Input Capacitance 5pF
TERMINATION SWITCH CHARACTERISTICS
(RT, GT, BT)
Input Capacitance VIN = 0 V 6 pF
Switch On Resistance VIN = 0 V 5.2 Ω
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 µA
Logic HI Input Current (DC) 0.020 0.70 µA
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
Chroma Level Error
1
Switch Input Termination 4 %
Chroma Phase Error
2
± 3 Degree
Color Burst Width NTSC 2.51 µs
PAL 2.26 µs
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 kΩ
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
Composite Output Connected
3
75 Ω Load, Active Termination, 30 39 mA
S-Video Inactive
S-Video Output Connected
3
75 Ω Load, Active Termination, 41 49 mA
Composite Output Inactive
Power-Down Current 0.09 0.7 µA
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% avera ge picture level. Larger current consumption possible for other levels.
Specifications subject to change without notice.
REV. 0
AD723
–3–
ABSOLUTE MAXIMUM RATINGS*
Supply Voltage, AVDD to AGND . . . . . . . . . . . . . . . . . . . 6 V
Supply Voltage, DVDD to DGND . . . . . . . . . . . . . . . . . . 6 V
AVDD to DVDD . . . . . . . . . . . . . . . . . . . . . –0.3 V to +0.3 V
AGND to DGND . . . . . . . . . . . . . . . . . . . . . –0.3 V to +0.3 V
Inputs . . . . . . . . . . . . . . . . . . DGND – 0.3 to DVDD + 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 60 sec) . . . . . . . . . 300°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
28-lead TSSOP package: θ
JA
= 67.7°C/W.
Thermal Resistance measured on SEMI standard 4-layer board.
PIN CONFIGURATION
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 AD723 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
ORDERING GUIDE
Temperature Package Package
Model Range Description Option
AD723ARU –40°C to +85°C 28-Lead TSSOP RU-28
AD723ARU-REEL –40°C to +85°C 28-Lead TSSOP RU-28
AD723-EVAL Evaluation Board
TOP VIEW
(Not to Scale)
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
AD723
DGND
DVDD
TGND
BT
GT
RT
AGND
STND
SA
CE
TERM
BIN
GIN
RIN
HSYNC
VSYNC
4FSC
TVDET
CVSET
CV
YTRAP
AGND
YSET
Y
AVDD1
AVDD
C
CSET
REV. 0
AD723
–4–
APOS
AGND
APOS
DPOS
DGND
POS
POS
APOS
AGNDAGND
APOS
DGNDDGND
DPOS
DPOS
TGND
1k⍀
1k⍀
19
24
26
27
20
23
18
10
11
9
6
7
5
2
3
1
16
17
15
4
21
PIN FUNCTION DESCRIPTIONS
Pin Mnemonic Description Equivalent Circuit
1 STND Encoding Standard Pin. A Logic HIGH signal is used for NTSC encoding, a Logic LOW Circuit A
signal signifies PAL.
2 SA When SA is high, phase alternation accompanies NTSC bandwidths and timing for Circuit A
support of PAL (M) and “combination N” standards used in South America.
3 CE Chip Enable. A Logic HIGH input enables the encode function. A Logic LOW input Circuit A
powers down the chip when not in use. Requires active HSYNC signal to activate.
Can be raised briefly to perform power-down load check.
4 TERM Terminate. A Logic HIGH enables terminate function. RT, GT, and BT terminals are Circuit A
tied to the termination ground, TGND. A Logic Low leaves these terminals floating.
5 RIN Red Component Video Input. 0 mV to 714 mV ac-coupled. Circuit B
6 GIN Green Component Video Input. 0 mV to 714 mV ac-coupled. Circuit B
7 BIN Blue Component Video Input. 0 mV to 714 mV ac-coupled. Circuit B
8 AGND Analog Ground Connection. (Main Ground Connection.)
9 RT Input Terminal for RED Termination Switch. Can be left unconnected when switchable Circuit F
input termination option is not used.
10 GT Input Terminal for GREEN Termination Switch. Can be left unconnected when switchable Circuit F
input termination option is not used.
11 BT Input Terminal for BLUE Termination Switch. Can be left unconnected when switchable Circuit F
input termination option is not used.
12 TGND Termination Switch Ground Connection.
13 DVDD Digital Positive Supply Connection.
14 DGND Digital Ground Connection.
15 HSYNC Horizontal Sync Signal (or CSYNC signal). Circuit A
16 VSYNC Vertical Sync Signal. Circuit A
17 4FSC 4FSC Clock Input. For NTSC: 14.318 180 MHz, for PAL: 17.734 475 MHz. Circuit A
18 TVDET Output Flag for TV Presence Detection. LOW signal signifies no TV present. Circuit E
19 CVSET Composite Video Gain Setting Resistor. Circuit C
20 CV Composite Video Output. Circuit C
21 YTRAP Luminance Trap Filter Tap. Attach L-C resonant network to reduce cross-color artifacts. Circuit D
22 AVDD Analog Positive Supply Connection.
23 C Chrominance Output. Circuit C
24 CSET Chrominance Gain Setting Resistor. Circuit C
25 AVDD1 Analog Positive Supply Connection.
26 Y Luminance Output (with CSYNC). Circuit C
27 YSET Luminance Gain Setting Resistor. Circuit C
28 AGND Analog Ground Connection.
Figure 1. Equivalent Circuits
Circuit A Circuit B Circuit C Circuit D
Circuit E Circuit F
REV. 0
–5–
AD723
Typical Performance Characteristics–
IRE
µs
1.0
0.5
–0.5
06010 20 30 40 50
0.0
APL = 51.2%
525 LINE NTSC NO FILTERING
SLOW CLAMP TO 0.0V @ 6.63
s
100
50
0
–50
VOLTS
TPC 2. 100% Color Bars, NTSC
NOISE REDUCTION: 15.05dB
APL = 50.7%
SETUP 7.5%
SYSTEM LINE L147 F1
ANGLE (DEG) 0.0
GAIN ⴛ 0.750 –2.499dB
525 LINE NTSC
BURST FROM SOURCE
TPC 3. 100% Color Bars on Vector Scope, NTSC
RGB
3
75⍀
75⍀
COMPOSITE
VIDEO
COMPOSITE
SYNC
FSC
GENLOCK
TEKTRONIX
TG2000
SIGNAL
GENERATION
PLATFORM
AD723
RGB-TO-
NTSC/PAL
ENCODER
TEKTRONIX
VM700A
WAVEFORM
MONITOR
SONY
MONITOR
MODEL
PVM-1354Q
3V
4FSC
HP3314A
ⴛ 4 PLL
FSC
(3.579545MHz
OR
4.433618MHz)
OSCILLATOR
TPC 1. Evaluation Setup
s
1.0
0.5
–0.5
06010 20 30 40 50
0.0
VOLTS
APL = 51.2%
625 LINE PAL NO FILTERING
SLOW CLAMP TO 0.00V @ 6.72
s
TPC 4. 100% Color Bars, PAL
NOISE REDUCTION: 15.05dB
APL = 51.0%
SOUND IN SYNC OFF
SYSTEM LINE L29
ANGLE (DEG) 0.0
GAIN ⴛ 0.750 –2.499dB
625 LINE PAL
BURST FROM SOURCE
DISPLAY +V AND –V
TPC 5. 100% Color Bars on Vector Scope, PAL
REV. 0
AD723
–6–
APL = 46.6%
525 LINE NTSC NO FILTERING
SLOW CLAMP TO 0.00V @ 6.63s
s
06010 20 30 40 50
IRE
1.0
0.5
–0.5
0.0
100
50
0
–50
VOLTS
TPC 6. Modulated Pulse and Bar, NTSC
200mV 1
s
TPC 7. Zoom on Modulated Pulse, NTSC
s
1.0
0.5
–0.5
06010 20 30 40 50
0.0
APL = 34.8%
625 LINE PAL NO FILTERING
SLOW CLAMP TO 0.00V @ 6.72 s
VOLTS
TPC 8. Modulated Pulse and Bar, PAL
200mV 1
s
TPC 9. Zoom on Modulated Pulse, PAL
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