ADV7123 [ADI]

CMOS, 240 MHz Triple 10-Bit High Speed Video DAC; CMOS , 240 MHz的三路10位高速视频DAC
ADV7123
型号: ADV7123
厂家: ADI    ADI
描述:

CMOS, 240 MHz Triple 10-Bit High Speed Video DAC
CMOS , 240 MHz的三路10位高速视频DAC

文件: 总20页 (文件大小:333K)
中文:  中文翻译
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CMOS, 330 MHz  
Triple 10-Bit High Speed Video DAC  
a
ADV7123  
FEATURES  
330 MSPS Throughput Rate  
FUNCTIONAL BLOCK DIAGRAM  
V
AA  
Triple 10-Bit D/A Converters  
SFDR  
–70 dB at fCLK = 50 MHz; fOUT = 1 MHz  
–53 dB at fCLK = 140 MHz; fOUT = 40 MHz  
RS-343A/RS-170 Compatible Output  
Complementary Outputs  
DAC Output Current Range 2 mA to 26 mA  
TTL Compatible Inputs  
Internal Reference (1.23 V)  
BLANK  
SYNC  
BLANK AND  
SYNC LOGIC  
IOR  
DATA  
R9–R0  
10  
10  
10  
10  
10  
10  
DAC  
DAC  
DAC  
REGISTER  
IOR  
IOG  
DATA  
REGISTER  
G9–G0  
B9–B0  
IOG  
Single-Supply 5 V/3.3 V Operation  
48-Lead LQFP Package  
IOB  
DATA  
REGISTER  
IOB  
Low Power Dissipation (30 mW Min @ 3 V)  
Low Power Standby Mode (6 mW Typ @ 3 V)  
Industrial Temperature Range (–40؇C to +85؇C)  
VOLTAGE  
REFERENCE  
CIRCUIT  
POWER-DOWN  
MODE  
PSAVE  
V
REF  
CLOCK  
ADV7123  
APPLICATIONS  
Digital Video Systems (1600 
؋
 1200 @ 100 Hz)  
High Resolution Color Graphics  
Digital Radio Modulation  
Image Processing  
R
COMP  
GND  
SET  
Instrumentation  
Video Signal Reconstruction  
GENERAL DESCRIPTION  
PRODUCT HIGHLIGHTS  
1. 330 MSPS throughput  
The ADV7123 (ADV®) is a triple high speed, digital-to-analog  
converter on a single monolithic chip. It consists of three  
high speed, 10-bit, video D/A converters with complementary  
outputs, a standard TTL input interface, and a high impedance,  
analog output current source.  
2. Guaranteed monotonic to 10 bits  
3. Compatible with a wide variety of high resolution color  
graphics systems, including RS-343A and RS-170  
The ADV7123 has three separate 10-bit-wide input ports. A  
single 5 V/3.3 V power supply and clock are all that are required  
to make the part functional. The ADV7123 has additional video  
control signals, composite SYNC and BLANK.  
The ADV7123 also has a Power-Save Mode.  
The ADV7123 is fabricated in a 5 V CMOS process. Its mono-  
lithic CMOS construction ensures greater functionality with  
lower power dissipation. The ADV7123 is available in a  
48-lead LQFP package.  
ADV is a registered trademark of Analog Devices, Inc.  
REV. B  
Information furnished by Analog Devices is believed to be accurate and  
reliable. However, no responsibility is assumed by Analog Devices for its  
use, norforanyinfringementsofpatentsorotherrightsofthirdpartiesthat  
may result from its use. No license is granted by implication or otherwise  
under any patent or patent rights of Analog Devices.  
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.  
Tel: 781/329-4700  
Fax: 781/326-8703  
www.analog.com  
© Analog Devices, Inc., 2002  
ADV7123–SPECIFICATIONS  
(VAA = 5 V ؎ 5%, VREF = 1.235 V, RSET = 560 , CL = 10 pF. All specifications TMIN to TMAX1, unless other-  
wise noted, TJ MAX = 110؇C.)  
5 V SPECIFICATIONS  
Parameter  
Min  
Typ  
Max  
Unit  
Test Conditions1  
STATIC PERFORMANCE  
Resolution (Each DAC)  
Integral Nonlinearity (BSL)  
Differential Nonlinearity  
10  
–1  
–1  
Bits  
LSB  
LSB  
0.4  
0.25  
+1  
+1  
Guaranteed Monotonic  
VIN = 0.0 V or VDD  
DIGITAL AND CONTROL INPUTS  
Input High Voltage, VIH  
Input Low Voltage, VIL  
Input Current, IIN  
PSAVE Pull-Up Current  
Input Capacitance, CIN  
2
V
V
µA  
µA  
pF  
0.8  
+1  
–1  
20  
10  
ANALOG OUTPUTS  
Output Current  
2.0  
2.0  
26.5  
18.5  
5
mA  
mA  
%
V
kΩ  
pF  
Green DAC, Sync = High  
RGB DAC, Sync = Low  
DAC to DAC Matching  
Output Compliance Range, VOC  
Output Impedance, ROUT  
Output Capacitance, COUT  
Offset Error  
1.0  
0
1.4  
100  
10  
IOUT = 0 mA  
Tested with DAC Output = 0 V  
FSR = 17.62 mA  
–0.025  
–5.0  
+0.025  
+5.0  
% FSR  
% FSR  
Gain Error2  
VOLTAGE REFERENCE (Ext. and Int.)  
Reference Range, VREF  
1.12  
1.235  
1.35  
V
POWER DISSIPATION  
Digital Supply Current3  
3.4  
10.5  
18  
67  
8
9
mA  
mA  
mA  
mA  
mA  
mA  
fCLK = 50 MHz  
fCLK = 140 MHz  
15  
25  
72  
f
CLK = 240 MHz  
Analog Supply Current  
Standby Supply Current4  
RSET = 560 Ω  
RSET = 4933 Ω  
PSAVE = Low, Digital, and Control  
Inputs at VDD  
2.1  
5.0  
0.5  
Power Supply Rejection Ratio  
0.1  
%/%  
NOTES  
1Temperature range TMIN to TMAX: –40°C to +85°C at 50 MHz and 140 MHz, 0°C to 70°C at 240 MHz and 330 MHz.  
2Gain error = {(Measured (FSC)/Ideal (FSC) –1) × 100}, where Ideal = VREF /RSET × K × (3FFH) and K = 7.9896.  
3Digital supply is measured with continuous clock with data input corresponding to a ramp pattern and with an input level at 0 V and V DD  
4These maximum/minimum specifications are guaranteed by characterization to be over the 4.75 V to 5.25 V range.  
.
Specifications subject to change without notice.  
–2–  
REV. B  
ADV7123  
(VAA = 3.0 V–3.6 V, VREF = 1.235 V, RSET = 560 , CL = 10 pF. All specifications TMIN to TMAX2, unless  
3.3 V SPECIFICATIONS1 otherwise noted, TJ MAX = 110؇C.)  
Parameter  
Min  
Typ  
Max  
Unit  
Test Conditions2  
STATIC PERFORMANCE  
Resolution (Each DAC)  
Integral Nonlinearity (BSL)  
Differential Nonlinearity  
10  
+1  
+1  
Bits  
LSB  
LSB  
RSET = 680 Ω  
RSET = 680 Ω  
RSET = 680 Ω  
–1  
–1  
+0.5  
+0.25  
DIGITAL AND CONTROL INPUTS  
Input High Voltage, VIH  
Input Low Voltage, VIL  
Input Current, IIN  
PSAVE Pull-Up Current  
Input Capacitance, CIN  
2.0  
–1  
V
V
µA  
µA  
pF  
0.8  
+1  
VIN = 0.0 V or VDD  
20  
10  
ANALOG OUTPUTS  
Output Current  
2.0  
2.0  
26.5  
18.5  
mA  
mA  
%
V
kΩ  
pF  
Green DAC, Sync = High  
RGB DAC, Sync = Low  
DAC to DAC Matching  
Output Compliance Range, VOC  
Output Impedance, ROUT  
Output Capacitance, COUT  
Offset Error  
1.0  
0
1.4  
0
70  
10  
0
% FSR  
% FSR  
Tested with DAC Output = 0 V  
FSR = 17.62 mA  
Gain Error3  
0
VOLTAGE REFERENCE (Ext.)  
Reference Range, VREF  
1.12  
1.235  
1.235  
1.35  
V
V
VOLTAGE REFERENCE (Int.)  
Reference Range, VREF  
POWER DISSIPATION  
Digital Supply Current4  
2.2  
6.5  
11  
16  
67  
8
5.0  
12.0  
15  
mA  
mA  
mA  
mA  
mA  
mA  
mA  
fCLK = 50 MHz  
f
CLK = 140 MHz  
fCLK = 240 MHz  
CLK = 330 MHz  
f
Analog Supply Current  
Standby Supply Current  
72  
RSET = 560 Ω  
RSET = 4933 Ω  
PSAVE = Low, Digital, and Control  
Inputs at VDD  
2.1  
5.0  
0.5  
Power Supply Rejection Ratio  
0.1  
%/%  
NOTES  
1These maximum/minimum specifications are guaranteed by characterization to be over the 3.0 V to 3.6 V range.  
2Temperature range TMIN to TMAX: –40°C to +85°C at 50 MHz and 140 MHz, 0°C to 70°C at 240 MHz and 330 MHz.  
3Gain error = {(Measured (FSC)/Ideal (FSC) –1) × 100}, where Ideal = VREF /RSET × K × (3FFH) and K = 7.9896.  
4Digital supply is measured with continuous clock with data input corresponding to a ramp pattern and with an input level at 0 V and V DD  
Specifications subject to change without notice.  
.
REV. B  
–3–  
ADV7123  
(VAA = 5 V ؎ 5%1, VREF = 1.235 V, RSET = 560 , CL = 10 pF. All specifications are  
TA = 25؇C, unless otherwise noted, TJ MAX = 110؇C.)  
5 V DYNAMIC SPECIFICATIONS1  
Parameter  
Min  
Typ  
Max  
Unit  
AC LINEARITY  
Spurious-Free Dynamic Range to Nyquist2  
Single-Ended Output  
fCLK = 50 MHz; fOUT = 1.00 MHz  
fCLK = 50 MHz; fOUT = 2.51 MHz  
67  
67  
63  
55  
62  
60  
54  
48  
57  
58  
52  
41  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
f
CLK = 50 MHz; fOUT = 5.04 MHz  
fCLK = 50 MHz; fOUT = 20.2 MHz  
fCLK = 100 MHz; fOUT = 2.51 MHz  
f
CLK = 100 MHz; fOUT = 5.04 MHz  
fCLK = 100 MHz; fOUT = 20.2 MHz  
fCLK = 100 MHz; fOUT = 40.4 MHz  
f
CLK = 140 MHz; fOUT = 2.51 MHz  
fCLK = 140 MHz; fOUT = 5.04 MHz  
fCLK = 140 MHz; fOUT = 20.2 MHz  
f
CLK = 140 MHz; fOUT = 40.4 MHz  
Double-Ended Output  
fCLK = 50 MHz; fOUT = 1.00 MHz  
70  
70  
65  
54  
67  
63  
58  
52  
62  
61  
55  
53  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
f
f
CLK = 50 MHz; fOUT = 2.51 MHz  
CLK = 50 MHz; fOUT = 5.04 MHz  
fCLK = 50 MHz; fOUT = 20.2 MHz  
f
f
CLK = 100 MHz; fOUT = 2.51 MHz  
CLK = 100 MHz; fOUT = 5.04 MHz  
fCLK = 100 MHz; fOUT = 20.2 MHz  
f
f
CLK = 100 MHz; fOUT = 40.4 MHz  
CLK = 140 MHz; fOUT = 2.51 MHz  
fCLK = 140 MHz; fOUT = 5.04 MHz  
f
f
CLK = 140 MHz; fOUT = 20.2 MHz  
CLK = 140 MHz; fOUT = 40.4 MHz  
Spurious-Free Dynamic Range within a Window  
Single-Ended Output  
fCLK = 50 MHz; fOUT = 1.00 MHz; 1 MHz Span  
fCLK = 50 MHz; fOUT = 5.04 MHz; 2 MHz Span  
77  
73  
64  
dBc  
dBc  
dBc  
f
CLK = 140 MHz; fOUT = 5.04 MHz; 4 MHz Span  
Double-Ended Output  
fCLK = 50 MHz; fOUT = 1.00 MHz; 1 MHz Span  
74  
73  
60  
dBc  
dBc  
dBc  
f
f
CLK = 50 MHz; fOUT = 5.00 MHz; 2 MHz Span  
CLK = 140 MHz; fOUT = 5.00 MHz; 4 MHz Span  
Total Harmonic Distortion  
fCLK = 50 MHz; fOUT = 1.00 MHz  
TA = 25°C  
66  
65  
64  
63  
55  
dBc  
dBc  
dBc  
dBc  
dBc  
TMIN to TMAX  
f
f
CLK = 50 MHz; fOUT = 2.00 MHz  
CLK = 100 MHz; fOUT = 2.00 MHz  
fCLK = 140 MHz; fOUT = 2.00 MHz  
DAC PERFORMANCE  
Glitch Impulse  
10  
23  
22  
33  
pVs  
dB  
dB  
dB  
DAC Crosstalk3  
Data Feedthrough4, 5  
Clock Feedthrough4, 5  
NOTES  
1These maximum/minimum specifications are guaranteed by characterization over the 4.75 V to 5.25 V range.  
2Note that the ADV7123 exhibits high performance when operating with an internal voltage reference, VREF  
.
3DAC to DAC Crosstalk is measured by holding one DAC high while the other two are making low to high and high to low transitions.  
4Clock and data feedthrough is a function of the amount of overshoot and undershoot on the digital inputs. Glitch impulse includes clock and data feedthrough.  
5TTL input values are 0 V to 3 V, with input rise/fall times of –3 ns, measured from the 10% and 90% points. Timing reference points are 50% for inputs and outputs.  
Specifications subject to change without notice.  
–4–  
REV. B  
ADV7123  
(VAA = 3.0 V–3.6 V1, VREF = 1.235 V, RSET = 680 , CL = 10 pF. All specifications are  
TA = 25؇C, unless otherwise noted, TJ MAX = 110؇C.)  
3.3 V DYNAMIC SPECIFICATIONS  
Parameter  
Min  
Typ  
Max  
Unit  
AC LINEARITY  
Spurious-Free Dynamic Range to Nyquist2  
Single-Ended Output  
fCLK = 50 MHz; fOUT = 1.00 MHz  
67  
67  
63  
55  
62  
60  
54  
48  
57  
58  
52  
41  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
f
CLK = 50 MHz; fOUT = 2.51 MHz  
fCLK = 50 MHz; fOUT = 5.04 MHz  
fCLK = 50 MHz; fOUT = 20.2 MHz  
f
CLK = 100 MHz; fOUT = 2.51 MHz  
fCLK = 100 MHz; fOUT = 5.04 MHz  
fCLK = 100 MHz; fOUT = 20.2 MHz  
f
CLK = 100 MHz; fOUT = 40.4 MHz  
fCLK = 140 MHz; fOUT = 2.51 MHz  
fCLK = 140 MHz; fOUT = 5.04 MHz  
f
CLK = 140 MHz; fOUT = 20.2 MHz  
fCLK = 140 MHz; fOUT = 40.4 MHz  
Double-Ended Output  
fCLK = 50 MHz; fOUT = 1.00 MHz  
70  
70  
65  
54  
67  
63  
58  
52  
62  
61  
55  
53  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
f
CLK = 50 MHz; fOUT = 2.51 MHz  
fCLK = 50 MHz; fOUT = 5.04 MHz  
f
f
CLK = 50 MHz; fOUT = 20.2 MHz  
CLK = 100 MHz; fOUT = 2.51 MHz  
fCLK = 100 MHz; fOUT = 5.04 MHz  
f
f
CLK = 100 MHz; fOUT = 20.2 MHz  
CLK = 100 MHz; fOUT = 40.4 MHz  
fCLK = 140 MHz; fOUT = 2.51 MHz  
f
f
CLK = 140 MHz; fOUT = 5.04 MHz  
CLK = 140 MHz; fOUT = 20.2 MHz  
fCLK = 140 MHz; fOUT = 40.4 MHz  
Spurious-Free Dynamic Range within a Window  
Single-Ended Output  
fCLK = 50 MHz; fOUT = 1.00 MHz; 1 MHz Span  
77  
73  
64  
dBc  
dBc  
dBc  
f
f
CLK = 50 MHz; fOUT = 5.04 MHz; 2 MHz Span  
CLK = 140 MHz; fOUT = 5.04 MHz; 4 MHz Span  
Double-Ended Output  
fCLK = 50 MHz; fOUT = 1.00 MHz; 1 MHz Span  
74  
73  
60  
dBc  
dBc  
dBc  
f
CLK = 50 MHz; fOUT = 5.00 MHz; 2 MHz Span  
fCLK = 140 MHz; fOUT = 5.00 MHz; 4 MHz Span  
Total Harmonic Distortion  
f
CLK = 50 MHz; fOUT = 1.00 MHz  
TA = 25°C  
66  
65  
64  
64  
55  
dBc  
dBc  
dBc  
dBc  
dBc  
TMIN to TMAX  
f
CLK = 50 MHz; fOUT = 2.00 MHz  
fCLK = 100 MHz; fOUT = 2.00 MHz  
fCLK = 140 MHz; fOUT = 2.00 MHz  
DAC PERFORMANCE  
Glitch Impulse  
10  
23  
22  
33  
pVs  
dB  
dB  
dB  
DAC Crosstalk3  
Data Feedthrough4, 5  
Clock Feedthrough4, 5  
NOTES  
1These maximum/minimum specifications are guaranteed by characterization over the 3.0 V to 3.6 V range.  
2Note that the ADV7123 exhibits high performance when operating with an internal voltage reference, VREF  
.
3DAC to DAC Crosstalk is measured by holding one DAC high while the other two are making low to high and high to low transitions.  
4Clock and data feedthrough is a function of the amount of overshoot and undershoot on the digital inputs. Glitch impulse includes clock and data feedthrough.  
5TTL input values are 0 V to 3 V, with input rise/fall times of –3 ns, measured at the 10% and 90% points. Timing reference points are 50% for inputs and outputs.  
Specifications subject to change without notice.  
REV. B  
–5–  
ADV7123  
(VAA = 5 V ؎ 5%2, VREF = 1.235 V, RSET = 560 , CL = 10 pF. All specifications TMIN to TMAX  
,
3
5 V TIMING SPECIFICATIONS1 unless otherwise noted, TJ MAX = 110؇C.)  
Parameter  
Min  
Typ  
Max  
Unit  
Condition  
ANALOG OUTPUTS  
Analog Output Delay, t6  
Analog Output Rise/Fall Time, t7  
5.5  
1.0  
15  
1
ns  
ns  
ns  
ns  
4
5
Analog Output Transition Time, t8  
6
Analog Output Skew, t9  
2
CLOCK CONTROL  
7
fCLK  
fCLK  
fCLK  
0.5  
0.5  
0.5  
50  
140  
240  
MHz  
MHz  
MHz  
50 MHz Grade  
140 MHz Grade  
240 MHz Grade  
7
7
Data and Control Setup, t1  
Data and Control Hold, t2  
Clock Pulsewidth High, t4  
Clock Pulsewidth Low t5  
Clock Pulsewidth High t4  
Clock Pulsewidth Low t5  
Clock Pulsewidth High t4  
Clock Pulsewidth Low t5  
0.5  
1.5  
1.875  
1.875  
2.85  
2.85  
8.0  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
fCLK  
fCLK  
fCLK  
fCLK  
fCLK  
fCLK  
_
_
_
_
_
_
MAX = 240 MHz  
MAX = 240 MHz  
MAX = 140 MHz  
MAX = 140 MHz  
MAX = 50 MHz  
MAX = 50 MHz  
8.0  
1.0  
6
Pipeline Delay, tPD  
1.0  
2
1.0  
10  
Clock Cycles  
ns  
6
PSAVE Up Time, t10  
NOTES  
1Timing specifications are measured with input levels of 3.0 V (VIH) and 0 V (VIL) 0 for both 5 V and 3.3 V supplies.  
2These maximum and minimum specifications are guaranteed over this range.  
3Temperature range: TMIN to TMAX: –40°C to +85°C at 50 MHz and 140 MHz, 0°C to 70°C at 240 MHz.  
4Rise time was measured from the 10% to 90% point of zero to full-scale transition, fall time from the 90% to 10% point of a full-scale transition.  
5Measured from 50% point of full-scale transition to 2% of final value.  
6Guaranteed by characterization.  
7fCLK max specification production tested at 125 MHz; 5 V limits specified here are guaranteed by characterization.  
Specifications subject to change without notice.  
–6–  
REV. B  
ADV7123  
(VAA = 3.0 V–3.6 V2, VREF = 1.235 V, RSET = 560 , CL = 10 pF. All specifications TMIN to  
3.3 V TIMING SPECIFICATIONS1  
TMAX3, unless otherwise noted, TJ MAX = 110؇C.)  
Parameter  
Min  
Typ  
Max  
Unit  
Condition  
ANALOG OUTPUTS  
Analog Output Delay, t6  
Analog Output Rise/Fall Time, t7  
7.5  
1.0  
15  
1
ns  
ns  
ns  
ns  
4
5
Analog Output Transition Time, t8  
6
Analog Output Skew, t9  
2
CLOCK CONTROL  
7
fCLK  
fCLK  
fCLK  
fCLK  
50  
MHz  
MHz  
MHz  
MHz  
50 MHz Grade  
140 MHz Grade  
240 MHz Grade  
330 MHz Grade  
7
140  
240  
330  
7
7
Data and Control Setup, t1  
0.2  
1.5  
1.4  
1.4  
ns  
ns  
ns  
ns  
Data and Control Hold, t2  
6
Clock Pulsewidth High, t4  
Clock Pulsewidth Low, t5  
fCLK_MAX = 330 MHz  
fCLK_MAX = 330 MHz  
fCLK_MAX = 240 MHz  
fCLK_MAX = 240 MHz  
fCLK_MAX = 140 MHz  
fCLK_MAX = 140 MHz  
fCLK_MAX = 50 MHz  
fCLK_MAX = 50 MHz  
6
Clock Pulsewidth High, t4  
Clock Pulsewidth Low t5  
Clock Pulsewidth High t4  
Clock Pulsewidth Low t5  
Clock Pulsewidth High t4  
Clock Pulsewidth Low t5  
1.875  
1.875  
2.85  
2.85  
8.0  
ns  
ns  
ns  
ns  
ns  
ns  
8.0  
1.0  
6
Pipeline Delay, tPD  
1.0  
4
1.0  
10  
Clock Cycles  
ns  
6
PSAVE Up Time, t10  
NOTES  
1Timing specifications are measured with input levels of 3.0 V (VIH) and 0 V (VIL) 0 for both 5 V and 3.3 V supplies.  
2These maximum and minimum specifications are guaranteed over this range.  
3Temperature range: TMIN to TMAX: –40°C to +85°C at 50 MHz and 140 MHz, 0°C to 70°C at 240 MHz and 330 MHz.  
4Rise time was measured from the 10% to 90% point of zero to full-scale transition, fall time from the 90% to 10% point of a full-scale transition.  
5Measured from 50% point of full-scale transition to 2% of final value.  
6Guaranteed by characterization.  
7fCLK max specification production tested at 125 MHz; 5 V limits specified here are guaranteed by characterization.  
Specifications subject to change without notice.  
t3  
t4  
t5  
CLOCK  
t2  
DIGITAL INPUTS  
(R9–R0, G9–G0, B9–B0,  
SYNC, BLANK)  
DATA  
t1  
t8  
t6  
ANALOG OUTPUTS  
(IOR, IOR, IOG, IOG, IOB, IOB)  
t7  
NOTES  
1. OUTPUT DELAY (t6) MEASURED FROM THE 50% POINT OF THE RISING EDGE OF CLOCK  
TO THE 50% POINT OF FULL-SCALE TRANSITION.  
2. OUTPUT RISE/FALL TIME (t7) MEASURED BETWEEN THE 10% AND 90% POINTS OF FULL-SCALE TRANSITION.  
3. TRANSITION TIME (t8) MEASURED FROM THE 50% POINT OF FULL-SCALE TRANSITION  
TO WITHIN 2% OF THE FINAL OUTPUT VALUE.  
Figure 1. Timing Diagram  
REV. B  
–7–  
ADV7123  
ABSOLUTE MAXIMUM RATINGS1  
NOTES  
1Stresses 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 listed in the operational sections  
of this specification is not implied. Exposure to absolute maximum rating condi-  
tions for extended periods may affect device reliability.  
VAA to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V  
Voltage on any Digital Pin . . . . . GND – 0.5 V to VAA + 0.5 V  
Ambient Operating Temperature (TA) . . . . . –40°C to +85°C  
Storage Temperature (TS) . . . . . . . . . . . . . . –65°C to +150°C  
Junction Temperature (TJ) . . . . . . . . . . . . . . . . . . . . . . 150°C  
Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . . 300°C  
Vapor Phase Soldering (1 Minute) . . . . . . . . . . . . . . . . 220°C  
IOUT to GND2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 V to VAA  
2Analog Output Short Circuit to any Power Supply or Common can be of an  
indefinite duration.  
ORDERING GUIDE  
Speed Options  
50 MHz1 140 MHz1  
Package  
240 MHz2  
330 MHz2, 3  
Plastic LQFP  
(ST-48)  
ADV7123KST50 ADV7123KST140 ADV7123JST240  
ADV7123JST330  
NOTES  
1Specified for –40°C to +85°C operation.  
2Specified for 0°C to 70°C operation.  
3Available in 3.3 V version only.  
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 ADV7123 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.  
PIN CONFIGURATION  
48 47 46 45 44 43 42 41 40 39 38 37  
1
2
36  
35  
G0  
G1  
V
REF  
PIN 1  
IDENTIFIER  
COMP  
3
G2  
34 IOR  
4
33  
32  
31  
30  
29  
28  
27  
26  
25  
G3  
IOR  
IOG  
IOG  
5
G4  
ADV7123  
TOP VIEW  
(Not to Scale)  
6
G5  
7
G6  
V
AA  
8
G7  
V
AA  
9
G8  
IOB  
10  
11  
12  
G9  
IOB  
BLANK  
SYNC  
GND  
GND  
13 14 15 16 17 18 19 20 21 22 23 24  
–8–  
REV. B  
ADV7123  
PIN FUNCTION DESCRIPTIONS  
Pin No. Mnemonic  
Function  
1–10  
G0–G9  
R0, G0, and B0 are the least significant data bits. Unused pixel data inputs should be connected to  
either the regular PCB power or ground plane.  
11  
BLANK  
Composite Blank Control Input (TTL Compatible). A logic zero on this control input drives the analog  
outputs, IOR, IOB, and IOG, to the blanking level. The BLANK signal is latched on the rising edge  
of CLOCK. While BLANK is a logical zero, the R0–R9, G0–G9, and B0–B9 pixel inputs are ignored.  
12  
SYNC  
Composite Sync Control Input (TTL Compatible). A logical zero on the SYNC input switches off a  
40 IRE current source. This is internally connected to the IOG analog output. SYNC does not over-  
ride any other control or data input; therefore, it should only be asserted during the blanking interval.  
SYNC is latched on the rising edge of CLOCK.  
If sync information is not required on the green channel, the SYNC input should be tied to logical zero.  
13, 29, 30 VAA  
Analog Power Supply (5 V 5%). All VAA pins on the ADV7123 must be connected.  
14–23  
B0–B9  
R0, G0, and B0 are the least significant data bits. Unused pixel data inputs should be connected to  
either the regular PCB power or ground plane.  
24  
CLOCK  
Clock Input (TTL Compatible). The rising edge of CLOCK latches the R0–R9, G0–G9, B0–B9,  
SYNC, and BLANK pixel and control inputs. It is typically the pixel clock rate of the video system.  
CLOCK should be driven by a dedicated TTL buffer.  
25, 26  
GND  
Ground. All GND pins must be connected.  
27, 31, 33 IOB, IOG, IOR Differential Red, Green, and Blue Current Outputs (High Impedance Current Sources). These RGB  
video outputs are specified to directly drive RS-343A and RS-170 video levels into a doubly terminated  
75 load. If the complementary outputs are not required, these outputs should be tied to ground.  
28, 32, 34 IOB, IOG, IOR Red, Green, and Blue Current Outputs. These high impedance current sources are capable of directly  
driving a doubly terminated 75 coaxial cable. All three current outputs should have similar output  
loads whether or not they are all being used.  
35  
COMP  
Compensation Pin. This is a compensation pin for the internal reference amplifier. A 0.1 µF ceramic  
capacitor must be connected between COMP and VAA  
.
36  
37  
VREF  
RSET  
Voltage Reference Input for DACs or Voltage Reference Output (1.235 V)  
A resistor (RSET) connected between this pin and GND controls the magnitude of the full-scale video  
signal. Note that the IRE relationships are maintained, regardless of the full-scale output current. For  
nominal video levels into a doubly terminated 75 load, RSET = 530 .  
The relationship between RSET and the full-scale output current on IOG (assuming ISYNC is connected  
to IOG) is given by:  
RSET ()  
= 11,445 × VREF (V)/IOG (mA)  
The relationship between RSET and the full-scale output current on IOR, IOG, and IOB is given by:  
IOG (mA)  
IOR, IOB (mA)  
= 11,445 × VREF (V)/RSET () (SYNC being asserted)  
= 7,989.6 × VREF (V)/RSET ()  
The equation for IOG will be the same as that for IOR and IOB when SYNC is not being used, i.e.,  
SYNC tied permanently low.  
38  
PSAVE  
Power Save Control Pin. Reduced power consumption is available on the ADV7123 when this pin is active.  
39–48  
R0–R9  
Red, Green, and Blue Pixel Data Inputs (TTL Compatible). Pixel data is latched on the rising edge of  
CLOCK.  
REV. B  
–9–  
ADV7123  
TERMINOLOGY  
Raster Scan  
Blanking Level  
The most basic method of sweeping a CRT one line at a time to  
generate and display images.  
The level separating the SYNC portion from the video portion  
of the waveform. Usually referred to as the front porch or back  
porch. At 0 IRE units, it is the level that will shut off the picture  
tube, resulting in the blackest possible picture.  
Reference Black Level  
The maximum negative polarity amplitude of the video signal.  
Reference White Level  
The maximum positive polarity amplitude of the video signal.  
Color Video (RGB)  
This usually refers to the technique of combining the three primary  
colors of red, green, and blue to produce color pictures within  
the usual spectrum. In RGB monitors, three DACs are required,  
one for each color.  
Sync Level  
The peak level of the SYNC signal.  
Video Signal  
The portion of the composite video signal that varies in gray  
scale levels between reference white and reference black. Also  
referred to as the picture signal, this is the portion that may be  
visually observed.  
Sync Signal (SYNC)  
The position of the composite video signal that synchronizes the  
scanning process.  
Gray Scale  
The discrete levels of video signal between reference black and  
reference white levels. A 10-bit DAC contains 1024 different  
levels, while an 8-bit DAC contains 256.  
–10–  
REV. B  
ADV7123  
5 V–Typical Performance Characteristics  
(VAA = 5 V, VREF = 1.235 V, IOUT = 17.62 mA, 50 Doubly Terminated Load, Differential Output Loading, TA = 25؇C)  
70  
60  
80  
70  
60  
50  
40  
30  
20  
72.0  
71.8  
71.6  
71.4  
71.2  
71.0  
70.8  
70.6  
70.4  
SFDR (DE)  
SFDR (DE)  
SFDR (SE)  
50  
40  
30  
20  
SFDR (SE)  
10  
0
10  
0
0.1  
1
2.51  
5.04  
20.2  
40.4  
100  
0.1  
1
2.51  
5.04  
20.2  
40.4  
100  
–10  
+25  
+85  
f
– MHz  
f
OUT  
– MHz  
OUT  
TEMPERATURE – ؇C  
TPC 1. SFDR vs. fOUT @ fCLOCK  
140 MHz (Single-Ended and  
Differential)  
=
TPC 2. SFDR vs. fOUT @ fCLOCK  
50 MHz (Single-Ended and Differential)  
=
TPC 3. SFDR vs. Temperature @  
f
CLOCK = 50 MHz (fOUT = 1 MHz)  
76  
1.0  
0.9  
0.8  
0.7  
0.6  
0.5  
0.4  
0.3  
0.2  
0.1  
0
1.00  
0.50  
SECOND  
74  
HARMONIC  
0.75  
72  
70  
68  
66  
THIRD  
HARMONIC  
FOURTH  
HARMONIC  
0.00  
1023  
–0.16  
64  
62  
60  
58  
–0.50  
–1.00  
0
50  
100  
fCLOCK – MHz  
140  
160  
0
2
17.62  
– mA  
20  
CODE – INL  
I
OUT  
TPC 4. THD vs. fCLOCK @ fOUT = 2 MHz  
(Second, Third, and Fourth Harmonics)  
TPC 5. Linearity vs. IOUT  
TPC 6. Typical Linearity (INL)  
–5.0  
–5.0  
–45.0  
–85.0  
–5.0  
–45.0  
–85.0  
–45.0  
–85.0  
0kHz  
START  
70.0MHz  
STOP  
35.0MHz  
0kHz  
START  
35.0MHz  
70.0MHz  
STOP  
35.0MHz  
70.0MHz  
STOP  
0kHz  
START  
TPC 9. Dual-Tone SFDR @ fCLOCK  
=
TPC 8. Single-Tone SFDR @ fCLOCK  
140 MHz (fOUT1 = 20 MHz)  
=
TPC 7. Single-Tone SFDR @ fCLOCK  
140 MHz (fOUT = 2 MHz)  
=
140 MHz (fOUT1 = 13.5 MHz, fOUT2  
14.5 MHz)  
=
REV. B  
–11–  
ADV7123  
3 V–Typical Performance Characteristics  
(VAA = 3 V, VREF = 1.235 V, IOUT = 17.62 mA, 50 Doubly Terminated Load, Differential Output Loading, TA = 25؇C)  
80  
70  
60  
50  
40  
30  
72.0  
71.8  
71.6  
71.4  
71.2  
71.0  
70.8  
70.6  
70.4  
70  
SFDR (DE)  
SFDR (SE)  
SFDR (DE)  
60  
SFDR (SE)  
50  
40  
30  
20  
20  
10  
0
10  
0
0.1  
2.51  
5.04  
20.2  
– MHz  
40.4  
100  
0.1  
1.0  
2.51 5.04 20.2  
– MHz  
40.4  
100  
0
20  
85  
145  
165  
f
TEMPERATURE – ؇C  
f
OUT  
OUT  
TPC 10. SFDR vs. fOUT @ fCLOCK  
140 MHz (Single-Ended and  
Differential)  
=
TPC 12. SFDR vs. Temperature @  
CLOCK = 50 MHz, (fOUT = 1 MHz)  
TPC 11. SFDR vs. fOUT @ fCLOCK  
140 MHz (Single-Ended and  
Differential)  
=
f
76  
1.00  
0.50  
0.00  
1.0  
0.9  
0.8  
0.7  
0.6  
0.5  
0.4  
0.3  
0.2  
SECOND HARMONIC  
74  
0.75  
FOURTH  
72  
HARMONIC  
70  
THIRD HARMONIC  
68  
1023  
66  
64  
62  
–0.42  
–0.50  
–1.00  
60  
58  
0.1  
0
0
50  
100  
140  
160  
CODE – INL  
0
2
17.62  
– mA  
20  
FREQUENCY – MHz  
I
OUT  
TPC 13. THD vs. fCLOCK @ fOUT  
2 MHz (Second, Third, and Fourth  
Harmonics)  
=
TPC 15. Typical Linearity  
TPC 14. Linearity vs. IOUT  
–5.0  
–5.0  
–45.0  
–85.0  
–5.0  
–45.0  
–85.0  
–45.0  
–85.0  
0kHz  
START  
0kHz  
START  
35.0MHz  
70.0MHz  
STOP  
0kHz  
START  
35.0MHz  
70.0MHz  
STOP  
35.0MHz  
70.0MHz  
STOP  
TPC 18. Dual-Tone SFDR @ fCLOCK  
=
TPC 16. Single-Tone SFDR @  
fCLOCK = 140 MHz (fOUT1 = 2 MHz)  
TPC 17. Single-Tone SFDR @  
CLOCK = 140 MHz (fOUT1 = 20 MHz)  
140 MHz (fOUT1 = 13.5 MHz, fOUT2  
14.5 MHz)  
=
f
–12–  
REV. B  
ADV7123  
CIRCUIT DESCRIPTION AND OPERATION  
This is done by adding appropriately weighted current sources  
to the analog outputs, as determined by the logic levels on the  
BLANK and SYNC digital inputs. Figure 3 shows the analog  
output, RGB video waveform of the ADV7123. The influence of  
SYNC and BLANK on the analog video waveform is illustrated.  
The ADV7123 contains three 10-bit D/A converters, with three  
input channels, each containing a 10-bit register. Also integrated  
on board the part is a reference amplifier. CRT control functions  
BLANK and SYNC are integrated on board the ADV7123.  
Digital Inputs  
Table I details the resultant effect on the analog outputs of  
Thirty bits of pixel data (color information) R0–R9, G0–G9,  
and B0–B9 are latched into the device on the rising edge of each  
clock cycle. This data is presented to the three 10-bit DACs and  
then converted to three analog (RGB) output waveforms. See  
Figure 2.  
BLANK and SYNC.  
All these digital inputs are specified to accept TTL logic levels.  
Clock Input  
The CLOCK input of the ADV7123 is typically the pixel clock  
rate of the system. It is also known as the dot rate. The dot rate,  
and thus the required CLOCK frequency, will be determined by  
the on-screen resolution according to the following equation:  
CLOCK  
DIGITAL INPUTS  
(R9–R0, G9–G0, B9–B0,  
Dot Rate = (Horiz Res) × (Vert Res) × (Refresh Rate)/  
(Retrace Factor)  
DATA  
SYNC, BLANK)  
Horiz Res  
Vert Res  
= Number of Pixels/Line.  
= Number of Lines/Frame.  
ANALOG OUTPUTS  
(IOR, IOG, IOB  
IOR, IOG, IOB)  
Refresh Rate  
= Horizontal Scan Rate. This is the rate at  
which the screen must be refreshed,  
typically 60 Hz for a noninterlaced system  
or 30 Hz for an interlaced system.  
Figure 2. Video Data Input/Output  
The ADV7123 has two additional control signals that are  
latched to the analog video outputs in a similar fashion. BLANK  
and SYNC are each latched on the rising edge of CLOCK to  
maintain synchronization with the pixel data stream.  
Retrace Factor  
= Total Blank Time Factor. This takes into  
account that the display is blanked for a  
certain fraction of the total duration of  
each frame (e.g., 0.8).  
The BLANK and SYNC functions allow for the encoding of  
these video synchronization signals onto the RGB video output.  
RED, BLUE  
GREEN  
mA  
mA  
V
V
18.62  
0.7  
26.67  
1.000  
WHITE LEVEL  
100 IRE  
BLANK LEVEL  
SYNC LEVEL  
0
0
8.05  
0.3  
43 IRE  
0
0
NOTES:  
1. OUTPUTS CONNECTED TO A DOUBLY TERMINATED 75LOAD.  
2. V = 1.235V, R = 530.  
REF SET  
3. RS-343A LEVELS AND TOLERANCES ASSUMED ON ALL LEVELS.  
Figure 3. RGB Video Output Waveform  
Table I. Video Output Truth Table (RSET = 530 , RLOAD = 37.5 )  
DAC  
Input Data  
Description  
IOG (mA)  
IOG (mA)  
IOR/IOB  
IOR/IOB  
SYNC  
BLANK  
WHITE LEVEL  
VIDEO  
26.67  
0
18.62  
Video  
Video  
0
0
0
0
0
1
1
0
1
0
1
0
1
1
1
1
1
0
0
3FFH  
Data  
Data  
000H  
000H  
xxxH  
xxxH  
Video + 8.05 18.62 – Video  
18.62 – Video  
18.62 – Video  
18.62  
18.62  
18.62  
VIDEO to BLANK  
BLACK LEVEL  
BLACK to BLANK  
BLANK LEVEL  
SYNC LEVEL  
Video  
8.05  
0
8.05  
0
18.62 – Video  
18.62  
18.62  
18.62  
18.62  
18.62  
REV. B  
–13–  
ADV7123  
Therefore, if we have a graphics system with a 1024 × 1024  
resolution, a noninterlaced 60 Hz refresh rate and a retrace  
factor of 0.8, then:  
Analog Outputs  
The ADV7123 has three analog outputs, corresponding to the  
red, green, and blue video signals.  
Dot Rate = 1024 × 1024 × 60/0.8  
The red, green, and blue analog outputs of the ADV7123 are  
high impedance current sources. Each one of these three RGB  
current outputs is capable of directly driving a 37.5 load, such  
as a doubly terminated 75 coaxial cable. Figure 4a shows the  
required configuration for each of the three RGB outputs con-  
nected into a doubly terminated 75 load. This arrangement  
will develop RS-343A video output voltage levels across a  
75 monitor.  
=
78.6 MHz  
The required CLOCK frequency is thus 78.6 MHz.  
All video data and control inputs are latched into the ADV7123  
on the rising edge of CLOCK, as described in the Digital Inputs  
section. It is recommended that the CLOCK input to the  
ADV7123 be driven by a TTL buffer (e.g., 74F244).  
Video Synchronization and Control  
A suggested method of driving RS-170 video levels into a 75 Ω  
monitor is shown in Figure 4b. The output current levels of the  
DACs remain unchanged, but the source termination resistance,  
ZS, on each of the three DACs is increased from 75 to 150 .  
The ADV7123 has a single composite sync (SYNC) input con-  
trol. Many graphics processors and CRT controllers have the  
ability of generating horizontal sync (HSYNC), vertical sync  
(VSYNC), and composite SYNC.  
IOR, IOG, IOB  
In a graphics system that does not automatically generate a  
composite SYNC signal, the inclusion of some additional logic  
circuitry will enable the generation of a composite SYNC signal.  
Z
= 75  
O
DACs  
(CABLE)  
Z
= 75⍀  
S
Z
= 75⍀  
L
(SOURCE  
TERMINATION)  
(MONITOR)  
The sync current is internally connected directly to the IOG  
output, thus encoding video synchronization information onto  
the green video channel. If it is not required to encode sync  
information onto the ADV7123, the SYNC input should be tied  
to logic low.  
TERMINATION REPEATED THREE TIMES  
FOR RED, GREEN, AND BLUE DACs  
Figure 4a. Analog Output Termination for RS-343A  
Reference Input  
The ADV7123 contains an on-board voltage reference. The  
VREF pin is normally terminated to VAA through a 0.1 µF capaci-  
tor. Alternatively, the part could, if required, be overdriven by  
an external 1.23 V reference (AD1580).  
IOR, IOG, IOB  
Z
= 75⍀  
O
DACs  
(CABLE)  
Z
= 150⍀  
(SOURCE  
TERMINATION)  
S
Z
= 75⍀  
L
(MONITOR)  
A resistance RSET connected between the RSET pin and GND  
determines the amplitude of the output video level according to  
Equations 1 and 2 for the ADV7123:  
TERMINATION REPEATED THREE TIMES  
FOR RED, GREEN, AND BLUE DACs  
IOG* (mA) = 11,445 × VREF (V)/RSET ()  
(1)  
Figure 4b. Analog Output Termination for RS-170  
IOR, IOB (mA) = 7,989.6 × VREF (V)/RSET ()  
(2)  
More detailed information regarding load terminations for vari-  
ous output configurations, including RS-343A and RS-170, is  
available in an Application Note entitled Video Formats &  
Required Load Terminations available from Analog Devices, pub-  
lication no. E1228–15–1/89.  
*Applies to the ADV7123 only when SYNC is being used. If SYNC is not being  
encoded onto the green channel, Equation 1 will be similar to Equation 2.  
Using a variable value of RSET, as shown in Figure 4, allows for  
accurate adjustment of the analog output video levels. Use of a  
fixed 560 RSET resistor yields the analog output levels as quoted  
in the specification page. These values typically correspond to  
the RS-343A video waveform values as shown in Figure 3.  
Figure 3 shows the video waveforms associated with the three  
RGB outputs driving the doubly terminated 75 load of  
Figure 4a. As well as the gray scale levels, Black Level to White  
Level, the diagram also shows the contributions of SYNC and  
BLANK for the ADV7123. These control inputs add appropri-  
ately weighted currents to the analog outputs, producing the specific  
output level requirements for video applications. Table I details how  
the SYNC and BLANK inputs modify the output levels.  
D/A Converters  
The ADV7123 contains three matched 10-bit D/A converters.  
The DACs are designed using an advanced, high speed, seg-  
mented architecture. The bit currents corresponding to each  
digital input are routed to either the analog output (bit = “1”) or  
GND (bit = “0”) by a sophisticated decoding scheme. As all this  
circuitry is on one monolithic device, matching between the  
three DACs is optimized. As well as matching, the use of identi-  
cal current sources in a monolithic design guarantees monoto-  
nicity and low glitch. The on-board operational amplifier stabilizes  
the full-scale output current against temperature and power  
supply variations.  
Gray Scale Operation  
The ADV7123 can be used for stand-alone, gray scale (mono-  
chrome), or composite video applications (i.e., only one channel  
used for video information). Any one of the three channels,  
RED, GREEN, or BLUE, can be used to input the digital video  
data. The two unused video data channels should be tied to  
logical zero. The unused analog outputs should be terminated  
with the same load as that for the used channel. In other words,  
if the red channel is used and IOR is terminated with a doubly  
terminated 75 load (37.5 ), IOB and IOG should be termi-  
nated with 37.5 resistors. See Figure 5.  
–14–  
REV. B  
ADV7123  
Ground Planes  
DOUBLY  
TERMINATED  
75LOAD  
VIDEO  
INPUT  
R0  
R9  
The ADV7123, and associated analog circuitry, should have a  
separate ground plane referred to as the analog ground plane.  
This ground plane should connect to the regular PCB ground  
plane at a single point through a ferrite bead, as illustrated in  
Figure 7. This bead should be located as close as possible  
(within three inches) to the ADV7123.  
IOR  
IOG  
ADV7123  
37.5⍀  
37.5⍀  
G0  
G9  
IOB  
B0  
B9  
GND  
The analog ground plane should encompass all ADV7123  
ground pins, voltage reference circuitry, power supply bypass  
circuitry, the analog output traces, and any output amplifiers.  
Figure 5. Input and Output Connections for Stand-Alone  
Gray Scale or Composite Video  
The regular PCB ground plane area should encompass all the  
digital signal traces, excluding the ground pins, leading up to  
the ADV7123.  
Video Output Buffers  
The ADV7123 is specified to drive transmission line loads, as  
are most monitors rated. The analog output configurations to  
drive such loads are described in the Analog Interface section  
and illustrated in Figure 5. However, in some applications it may  
be required to drive long “transmission line” cable lengths. Cable  
lengths greater than 10 meters can attenuate and distort high  
frequency analog output pulses. The inclusion of output buffers  
will compensate for some cable distortion. Buffers with large full  
power bandwidths and gains between two and four will be required.  
These buffers will also need to be able to supply sufficient current  
over the complete output voltage swing. Analog Devices pro-  
duces a range of suitable op amps for such applications. These  
include the AD84x series of monolithic op amps. In very high  
frequency applications (80 MHz), the AD8061 is recommended.  
More information on line driver buffering circuits is given in the  
relevant op amp data sheets.  
Power Planes  
The PC board layout should have two distinct power planes,  
one for analog circuitry and one for digital circuitry. The analog  
power plane should encompass the ADV7123 (VAA) and all  
associated analog circuitry. This power plane should be con-  
nected to the regular PCB power plane (VCC) at a single point  
through a ferrite bead, as illustrated in Figure 7. This bead  
should be located within three inches of the ADV7123.  
The PCB power plane should provide power to all digital logic  
on the PC board, and the analog power plane should provide  
power to all ADV7123 power pins, voltage reference circuitry,  
and any output amplifiers.  
The PCB power and ground planes should not overlay portions  
of the analog power plane. Keeping the PCB power and ground  
planes from overlaying the analog power plane will contribute to  
a reduction in plane-to-plane noise coupling.  
Use of buffer amplifiers also allows implementation of other video  
standards besides RS-343A and RS-170. Altering the gain compo-  
nents of the buffer circuit will result in any desired video level.  
Supply Decoupling  
Noise on the analog power plane can be further reduced by the  
use of multiple decoupling capacitors (see Figure 7).  
Z
Z
1
2
0.1F  
0.1F  
Optimum performance is achieved by the use of 0.1 µF ceramic  
capacitors. Each of the two groups of VAA should be individu-  
ally decoupled to ground. This should be done by placing the  
capacitors as close as possible to the device with the capacitor  
leads as short as possible, thus minimizing lead inductance.  
+V  
S
Z
= 75⍀  
O
IOR, IOG, IOB  
DACs  
75⍀  
AD848  
Z
= 75⍀  
L
(CABLE)  
(MONITOR)  
Z
= 75⍀  
S
–V  
S
It is important to note that while the ADV7123 contains cir-  
cuitry to reject power supply noise, this rejection decreases with  
frequency. If a high frequency switching power supply is used,  
the designer should pay close attention to reducing power  
supply noise. A dc power supply filter (Murata BNX002) will  
provide EMI suppression between the switching power supply  
and the main PCB. Alternatively, consideration could be  
given to using a three terminal voltage regulator.  
Z
Z
(SOURCE  
1
2
GAIN (G) = 1 +  
TERMINATION)  
Figure 6. AD848 As an Output Buffer  
PC Board Layout Considerations  
The ADV7123 is optimally designed for lowest noise perfor-  
mance, both radiated and conducted noise. To complement the  
excellent noise performance of the ADV7123, it is imperative  
that great care be given to the PC board layout. Figure 7  
shows a recommended connection diagram for the ADV7123.  
Digital Signal Interconnect  
The digital signal lines to the ADV7123 should be isolated as  
much as possible from the analog outputs and other analog  
circuitry. Digital signal lines should not overlay the analog  
power plane.  
The layout should be optimized for lowest noise on the ADV7123  
power and ground lines. This can be achieved by shielding the  
digital inputs and providing good decoupling. The lead length  
between groups of VAA and GND pins should be shortened to  
minimize inductive ringing.  
Due to the high clock rates used, long clock lines to the ADV7123  
should be avoided to minimize noise pickup.  
REV. B  
–15–  
ADV7123  
Any active pull-up termination resistors for the digital inputs  
should be connected to the regular PCB power plane (VCC) and  
not the analog power plane.  
For optimum performance, the analog outputs should each have  
a source termination resistance to ground of 75 (doubly  
terminated 75 configuration). This termination resistance  
should be as close as possible to the ADV7123 to minimize  
reflections.  
Analog Signal Interconnect  
The ADV7123 should be located as close as possible to the  
output connectors, thus minimizing noise pickup and reflections  
due to impedance mismatch.  
Additional information on PCB design is available in an application  
note entitled, Design and Layout of a Video Graphics System for  
Reduced EMI. This application note is available from Analog  
Devices, publication no. E1309–15–10/89.  
The video output signals should overlay the ground plane and  
not the analog power plane, thereby maximizing the high fre-  
quency power supply rejection.  
POWER SUPPLY DECOUPLING (0.1F AND 0.01F  
CAPACITOR FOR EACH V GROUP)  
AA  
L1  
0.1F  
0.01F  
13, 29,  
30  
(FERRITE BEAD)  
V
V
0.1F  
AA  
CC  
V
5V (V  
)
AA  
AA  
COMP  
R9–R0  
ANALOG GROUND PLANE  
0.1F  
10F  
33F  
39-48  
5V (V  
)
V
AA  
REF  
R
SET  
1-10  
R
530⍀  
SET  
MONITOR  
(CRT)  
VIDEO  
COAXIAL CABLE  
G9–G0  
B9–B0  
DATA  
75⍀  
INPUTS  
IOR  
IOG  
IOB  
14-23  
75⍀  
75⍀  
75⍀  
757575⍀  
ADV7123  
BNC  
CONNECTORS  
SYNC  
IOR  
BLANK  
COMPLEMENTARY  
OUTPUTS  
IOG  
IOB  
CLOCK  
PSAVE  
GND  
25, 26  
Figure 7. Typical Connection Diagram  
–16–  
REV. B  
ADV7123  
OUTLINE DIMENSIONS  
48-Lead Plastic Quad Flatpack [LQFP]  
1.4 mm Thick  
(ST-48)  
Dimensions shown in millimeters  
1.60 MAX  
PIN 1  
INDICATOR  
0.75  
0.60  
0.45  
9.00 BSC  
37  
48  
36  
1
SEATING  
PLANE  
1.45  
1.40  
1.35  
0.20  
0.09  
7.00  
BSC  
TOP VIEW  
(PINS DOWN)  
VIEW A  
7؇  
3.5؇  
0؇  
0.15  
0.05  
25  
12  
SEATING  
PLANE  
24  
0.08 MAX  
13  
COPLANARITY  
0.27  
0.22  
0.17  
0.50  
BSC  
VIEW A  
ROTATED 90؇ CCW  
COMPLIANT TO JEDEC STANDARDS MS-026BBC  
REV. B  
–17–  
ADV7123  
Revision History  
Location  
Page  
10/02—Data Sheet changed from REV. A to REV. B.  
Change in title . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1  
Change to FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1  
Change to PRODUCT HIGHLIGHTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1  
Change SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2  
Change to ORDERING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8  
Change to PIN FUNCTION DESCRIPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9  
Change to Reference Input section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14  
Change to Figure 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16  
Updated OUTLINE DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17  
–18–  
REV. B  
–19–  
–20–  

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