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a
FEATURES Excellent Video Performance Differential Gain & Phase Error of 0.01% & 0.05 High Speed 130 MHz 3 dB Bandwidth (G = +2) 450 V/ s Slew Rate 80 ns Settling Time to 0.01% Low Power 15 mA Max Power Supply Current High Output Drive Capability: 50 mA Minimum Output Current per Amplifier Ideal for Driving Back Terminated Cables Flexible Power Supply Specified for +5 V, 5 V and 15 V Operation 3.2 V Min Output Swing into a 150 Load (VS = 5 V) Excellent DC Performance 2.0 mV Input Offset Voltage Available in 8-Lead SOIC and 8-Lead Plastic Mini-DIP
OUT1 -IN1 +IN1 V- 1 2 3 4
Dual, Low Power Video Op Amp AD828
FUNCTIONAL BLOCK DIAGRAM
8 7 6 5 V+ OUT2 -IN2 +IN2
AD828
PRODUCT DESCRIPTION
The AD828 is a low cost, dual video op amp optimized for use in video applications which require gains of +2 or greater and high output drive capability, such as cable driving. Due to its low power and single supply functionality, along with excellent differential gain and phase errors, the AD828 is ideal for power sensitive applications such as video cameras and professional video equipment. With video specs like 0.1 dB flatness to 40 MHz and low differential gain and phase errors of 0.01% and 0.05, along with 50 mA of output current per amplifier, the AD828 is an excellent choice for any video application. The 130 MHz gain bandwidth and 450 V/s slew rate make the AD828 useful in many high speed applications including: video monitors, CATV, color copiers, image scanners and fax machines.
V 0.1 F
The AD828 is fully specified for operation with a single +5 V power supply and with dual supplies from 5 V to 15 V. This power supply flexibility, coupled with a very low supply current of 15 mA and excellent ac characteristics under all power supply conditions, make the AD828 the ideal choice for many demanding yet power sensitive applications. The AD828 is a voltage feedback op amp which excels as a gain stage (gains >+2) or active filter in high speed and video systems and achieves a settling time of 45 ns to 0.1%, with a low input offset voltage of 2 mV max. The AD828 is available in low cost, small 8-lead plastic miniDIP and SOIC packages.
DIFFERENTIAL GAIN - Percent
0.03
0.02 DIFF GAIN
DIFFERENTIAL PHASE - Degrees
VIN RT 75
1/2 AD828
0.1 F
RBT 75
75 RT 75
0.07
0.01
0.06 DIFF PHASE 0.05
-V 1k 1k
Figure 1. Video Line Driver
0.04
5
10 SUPPLY VOLTAGE -
15 Volts
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, 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.
Figure 2. Differential Phase vs. Supply Voltage
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 (c) Analog Devices, Inc., 2000
AD828-SPECIFICATIONS (@ T = +25 C, unless otherwise noted)
A
Parameter DYNAMIC PERFORMANCE -3 dB Bandwidth
Conditions Gain = +2 Gain = -1
VS 5 V 15 V 0, +5 V 5 V 15 V 0, +5 V 5 V 15 V 0, +5 V 5 V 15 V 0, +5 V 5 V 15 V 5 V 15 V 0, +5 V 5 V 15 V 5 V 15 V 15 V 5 V, 15 V 5 V, 15 V 15 V 5 V 0, +5 V 15 V 5 V 0, +5 V 5 V, 15 V
Min 60 100 30 35 60 20 30 30 10 15 30 10
AD828 Typ 85 130 45 55 90 35 43 40 18 25 50 19 22.3
Max
Unit MHz MHz MHz MHz MHz MHz MHz MHz MHz MHz MHz MHz MHz MHz V/s V/s V/s ns ns ns ns dB nV/Hz pA/Hz % % % Degrees Degrees Degrees mV mV V/C A A A nA nA nA/C V/mV V/mV V/mV V/mV V/mV V/mV k pF V V V V V V dB dB dB
Bandwidth for 0.1 dB Flatness
Gain = +2 CC = 1 pF Gain = -1 CC = 1 pF
Full Power Bandwidth1
Slew Rate Settling Time to 0.1% Settling Time to 0.01% NOISE/HARMONIC PERFORMANCE Total Harmonic Distortion Input Voltage Noise Input Current Noise Differential Gain Error (RL = 150 ) Differential Phase Error (RL = 150 ) DC PERFORMANCE Input Offset Voltage
VOUT = 5 V p-p RLOAD = 500 VOUT = 20 V p-p RLOAD = 1 k RLOAD 1 k Gain = -1 -2.5 V to +2.5 V 0 V-10 V Step, AV = -1 -2.5 V to +2.5 V 0 V-10 V Step, AV = -1 FC = 1 MHz f = 10 kHz f = 10 kHz NTSC Gain = +2 NTSC Gain = +2
300 400 200
7.2 350 450 250 45 45 80 80 -78 10 1.5 0.01 0.02 0.08 0.05 0.07 0.1 0.5 10 3.3 25 0.3
0.02 0.03 0.09 0.1
TMIN to TMAX Offset Drift Input Bias Current TMIN TMAX Input Offset Current TMIN to TMAX Offset Current Drift Open Loop Gain VOUT = 2.5 V RLOAD = 500 TMIN to TMAX RLOAD = 150 VOUT = 10 V RLOAD = 1 k TMIN to TMAX VOUT = 7.5 V RLOAD = 150 (50 mA Output) 5 V 3 2 2 5.5 2.5 3 5 4 9 5 300 1.5 +4.3 -3.4 +14.3 -13.4 +4.3 +0.9 100 120 100 5 V, 15 V 5 V, 15 V
2 3 6.6 10 4.4 300 500
15 V 15 V
INPUT CHARACTERISTICS Input Resistance Input Capacitance Input Common-Mode Voltage Range
5 V 15 V 0, +5 V
Common-Mode Rejection Ratio
VCM = +2.5 V, TMIN to TMAX VCM = 12 V TMIN to TMAX
5 V 15 V 15 V
+3.8 -2.7 +13 -12 +3.8 +1.2 82 86 84
-2-
REV. B
AD828
Parameter OUTPUT CHARACTERISTICS Output Voltage Swing Conditions RLOAD = 500 RLOAD = 150 RLOAD = 1 k RLOAD = 500 RLOAD = 500 Output Current Short-Circuit Current Output Resistance MATCHING CHARACTERISTICS Dynamic Crosstalk Gain Flatness Match Skew Rate Match DC Input Offset Voltage Match Input Bias Current Match Open-Loop Gain Match Common-Mode Rejection Ratio Match Power Supply Rejection Ratio Match POWER SUPPLY Operating Range Quiescent Current Power Supply Rejection Ratio
NOTES 1 Full power bandwidth = slew rate/2 VPEAK. Specifications subject to change without notice.
VS 5 V 5 V 15 V 15 V 0, +5 V 15 V 5 V 0, +5 V 15 V
Min 3.3 3.2 13.3 12.8 +1.5, +3.5 50 40 30
Typ 3.8 3.6 13.7 13.4
Max
Unit V V V V V mA mA mA mA
Open Loop
90 8
f = 5 MHz G = +1, f = 40 MHz G = -1 TMIN to TMAX TMIN to TMAX VO = 10 V, RL = 1 k, TMIN to TMAX VCM = 12 V, TMIN to TMAX 5 V to 15 V, TMIN to TMAX Dual Supply Single Supply TMIN to TMAX TMIN to TMAX VS = 5 V to 15 V, TMIN to TMAX
15 V 15 V 15 V 5 V, 15 V 5 V, 15 V 15 V 15 V
-80 0.2 10 0.5 0.06 0.01 100 100 2 0.8 0.15
dB dB V/s mV A mV/V dB dB V V mA mA mA dB
80 80 2.5 +5
5 V 5 V 5 V
14.0 14.0 80 90
18 +36 15 15 15
ORDERING GUIDE Model Temperature Range Package Description Package Option
ABSOLUTE MAXIMUM RATINGS 1
MAXIMUM POWER DISSIPATION - Watts
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 V Internal Power Dissipation2 Plastic DIP (N) . . . . . . . . . . . . . . . . . . See Derating Curves Small Outline (R) . . . . . . . . . . . . . . . . . See Derating Curves Input Voltage (Common Mode) . . . . . . . . . . . . . . . . . . . . VS Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . 6 V Output Short Circuit Duration . . . . . . . . See Derating Curves Storage Temperature Range (N, R) . . . . . . . -65C to +125C Operating Temperature Range . . . . . . . . . . . -40C to +85C Lead Temperature Range (Soldering 10 sec) . . . . . . . . +300C
NOTES 1 Stresses above those listed under Absolute Maximum Ratings may cause permanent 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. 2 Specification is for device in free air: 8-Lead Plastic DIP Package: JA = 100C/Watt 8-Lead SOIC Package: JA = 155C/Watt
AD828AN -40C to +85C AD828AR -40C to +85C AD828AR-REEL7 -40C to +85C AD828AR-REEL -40C to +85C
2.0
8-Lead Plastic DIP N-8 8-Lead Plastic SOIC SO-8 7" Tape & Reel SO-8 13" Tape & Reel SO-8
TJ = +150 C
8-LEAD MINI-DIP PACKAGE 1.5
1.0
0.5 8-LEAD SOIC PACKAGE
0 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 AMBIENT TEMPERATURE - C
80
90
Figure 3. Maximum Power Dissipation vs. Temperature for Different Package Types
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 AD828 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. B
-3-
AD828-Typical Characteristics
QUIESCENT SUPPLY CURRENT PER AMP - mA
20
Volts
7.7
INPUT COMMON-MODE RANGE -
15 +VCM 10 -V CM
7.2 +85C 6.7 -40C
+25C
5
6.2
0 0 5 10 SUPPLY VOLTAGE - 15 Volts 20
5.7 0 5 10 SUPPLY VOLTAGE - 15 Volts 20
Figure 4. Common-Mode Voltage Range vs. Supply Voltage
Figure 7. Quiescent Supply Current per Amp vs. Supply Voltage for Various Temperatures
20
500
Volts
15
450
OUTPUT VOLTAGE SWING -
RL = 500 10 RL = 150 5
SLEW RATE - V/ s
20
400
350
0
0
5
10 SUPPLY VOLTAGE -
15 Volts
300
0
5
10 SUPPLY VOLTAGE -
15 Volts
20
Figure 5. Output Voltage Swing vs. Supply Voltage
Figure 8. Slew Rate vs. Supply Voltage
30
OUTPUT VOLTAGE SWING - Volts p-p
100
CLOSED-LOOP OUTPUT IMPEDANCE -
10k
25 Vs = 20 15V
10
15
1
10 Vs = 5 5V
0.1
0 10
100 1k LOAD RESISTANCE -
0.01 1k
10k
100k 1M FREQUENCY - Hz
10M
100M
Figure 6. Output Voltage Swing vs. Load Resistance
Figure 9. Closed-Loop Output Impedance vs. Frequency
-4-
REV. B
AD828
7
100 PHASE 5V OR 15V SUPPLIES 80 15V SUPPLIES
OPEN-LOOP GAIN - dB
+100
6
+80
INPUT BIAS CURRENT - A
5
60
+60
4
40 5V SUPPLIES 20
+40
3
+20
2
0 RL = 1k
0
1 -60
-40
-20
0
20
40
60
80
100
120
140
-20 1k
10k
TEMPERATURE - C
100k 1M 10M FREQUENCY - Hz
100M
1G
Figure 10. Input Bias Current vs. Temperature
Figure 13. Open-Loop Gain and Phase Margin vs. Frequency
130
9 15V
SHORT CIRCUIT CURRENT - mA
8
110 SOURCE CURRENT 90 SINK CURRENT 70
OPEN-LOOP GAIN - V/mV
7 5V 6
5
50
4
30 -60
-40
-20
0
20
40
60
80
100
120
140
3 100
TEMPERATURE - C
1k LOAD RESISTANCE -
10k
Figure 11. Short Circuit Current vs. Temperature
Figure 14. Open-Loop Gain vs. Load Resistance
80
80
100 90 80
PHASE MARGIN - Degrees
-3dB BANDWIDTH - MHz
70 PHASE MARGIN
70
+SUPPLY 70 PSR - dB 60 50 -SUPPLY 40 30 20
60
60
GAIN BANDWIDTH 50 50
40 -60
-40
-20
0
20 40 60 80 TEMPERATURE - C
100
120
40 140
10 100
1k
10k 100k 1M FREQUENCY - Hz
10M
100M
Figure 12. -3 dB Bandwidth and Phase Margin vs. Temperature, Gain = +2
Figure 15. Power Supply Rejection vs. Frequency
REV. B
-5-
PHASE MARGIN - Degrees
AD828-Typical Characteristics
140 -40 VIN = 1V p-p GAIN = +2 -50 120
HARMONIC DISTORTION - dB
-60
CMR - dB
100
-70
-80 2ND HARMONIC -90 3RD HARMONIC
80
60 1k 10k 100k FREQUENCY - Hz 1M 10M
-100 100
1k
10k 100k FREQUENCY - Hz
1M
10M
Figure 16. Common-Mode Rejection vs. Frequency
Figure 19. Harmonic Distortion vs. Frequency
30
50
OUTPUT VOLTAGE - Volts p-p
Hz 20 INPUT VOLTAGE NOISE - nV/ 100M RL = 1k 10 RL = 150 0 100k 1M 10M FREQUENCY - Hz
40
30
20
10
0
0
10
100
1k 10k FREQUENCY - Hz
100k
1M
10M
Figure 17. Large Signal Frequency Response
Figure 20. Input Voltage Noise Spectral Density vs. Frequency
10 8 OUTPUT SWING FROM 0 TO V 6
650
550
1% 2 0 -2 -4 -6 -8 -10 0 20 40 60 80 100 SETTLING TIME - ns 120 140 160 1% 0.1% 0.01% 0.1% 0.01%
SLEW RATE - V/ s
4
450
350
250 -60
-40
-20
0
20
40
60
80
100
120
140
TEMPERATURE - C
Figure 18. Output Swing and Error vs. Settling Time
Figure 21. Slew Rate vs. Temperature
-6-
REV. B
AD828
10 8 6 4 VIN 1k 1k AD828 150 VS = 1pF VS 15V 5V +5V 15V 0.1dB FLATNESS 40MHz 43MHz 18MHz
5 1pF 4 3 2 VIN 1k 1k VOUT AD828 150 VS 15V 5V +5V 0.1dB FLATNESS 50MHz 25MHz 19MHz VS = 15V
VOUT
GAIN - dB
0 -2 -4 VS = -6 -8 -10 100k 5V VS = +5V
GAIN - dB
2
1 0 -1 -2 -3 -4 -5 100k VS = +5V VS =
5V
1M 10M FREQUENCY - Hz
100M
1M 10M FREQUENCY - Hz
100M
Figure 22. Closed-Loop Gain vs. Frequency
Figure 25. Closed-Loop Gain vs. Frequency, G = -1
DIFFERENTIAL GAIN - Percent
0.03
1.0 0.8 0.6 0.4
GAIN - dB
0.02 DIFF GAIN
DIFFERENTIAL PHASE - Degrees
0.07
0.01
0.2 0 -0.2 VS = -0.4 5V
VS =
15V
0.06
DIFF PHASE 0.05 -0.6 VS = -0.8 0.04 5 10 SUPPLY VOLTAGE - 15 Volts -1.0 100k 5V
1M 10M FREQUENCY - Hz
100M
Figure 23. Differential Gain and Phase vs. Supply Voltage
Figure 26. Gain Flatness Matching vs. Supply, G = +2
-30 -40
+5V 0.1 F VOUT 1F
-50 CROSSTALK - dB -60 -70 -80 -90 -100 -110 10k RL = 1k RL = 150
VIN
3 1/2
8
5 1 7 1/2
AD828
2
AD828
4 6
0.1 F RL RL 1F
-5V USE GROUND PLANE PINOUT SHOWN IS FOR MINIDIP PACKAGE
100k
1M FREQUENCY - Hz
10M
100M
Figure 24. Crosstalk vs. Frequency
Figure 27. Crosstalk Test Circuit
REV. B
-7-
AD828-Typical Characteristics
CF 1k +VS 3.3 F
100 90
5V
50ns
0.01 F HP PULSE (LS) V 1k OR FUNCTION IN (SS) GENERATOR 50 2 8
1/2 AD828
3 4
VOUT 1 0.01 F
TEKTRONIX P6201 FET PROBE RL
TEKTRONIX 7A24 PREAMP
10 0%
3.3 F -VS
5V
Figure 28. Inverting Amplifier Connection
Figure 31. Inverter Large Signal Pulse Response 15 VS, CF = 1 pF, RL = 1 k
2V
100 90
50ns
100 90
200mV
10ns
10 0%
10 0%
2V
200mV
Figure 29. Inverter Large Signal Pulse Response 5 VS, CF = 1 pF, RL = 1 k
Figure 32. Inverter Small Signal Pulse Response 15 VS, CF = 1 pF, RL= 1500
200mV
100 90
10ns
100 90
200mV
10ns
10 0%
10 0%
200mV
200mV
Figure 30. Inverter Small Signal Pulse Response 5 VS, CF = 1 pF, RL = 150
Figure 33. Inverter Small Signal Pulse Response 5 VS, CF = 0 pF, RL = 150
-8-
REV. B
AD828
CF
5V
1k 1k
100
50ns
+VS
3.3 F
90
0.01 F 2 HP PULSE (LS) VIN OR FUNCTION (SS) GENERATOR 100 3 50 3.3 F -VS 8
1/2 AD828
4
VOUT 1 0.01 F
TEKTRONIX P6201 FET PROBE RL
TEKTRONIX 7A24 PREAMP
10 0%
5V
Figure 34. Noninverting Amplifier Connection
Figure 37. Noninverting Large Signal Pulse Response 15 VS, CF = 1 pF, RL = 1 k
1V
100 90
50ns
100 90
100mV
10ns
10 0%
10 0%
2V
200mV
Figure 35. Noninverting Large Signal Pulse Response 5 VS, CF = 1 pF, RL = 1 k
Figure 38. Noninverting Small Signal Pulse Response 15 VS, CF = 1 pF, RL = 150
100mV
100 90
10ns
100 90
100mV
10ns
10 0%
10 0%
200mV
200mV
Figure 36. Noninverting Small Signal Pulse Response 5 VS, CF = 1 pF, RL = 150
Figure 39. Noninverting Small Signal Pulse Response 5 VS, CF = 0 pF, RL = 150
REV. B
-9-
AD828
THEORY OF OPERATION Circuit Board Layout
The AD828 is a low cost, dual video operational amplifier designed to excel in high performance, high output current video applications. The AD828 (Figure 40) consists of a degenerated NPN differential pair driving matched PNPs in a folded-cascode gain stage. The output buffer stage employs emitter followers in a class AB amplifier that delivers the necessary current to the load while maintaining low levels of distortion. The AD828 will drive terminated cables and capacitive loads of 10 pF or less. As the closed-loop gain is increased, the AD828 will drive heavier cap loads without oscillating.
+VS
Input and output runs should be laid out so as to physically isolate them from remaining runs. In addition, the feedback resistor of each amplifier should be placed away from the feedback resistor of the other amplifier, since this greatly reduces interamp coupling.
Choosing Feedback and Gain Resistors
In order to prevent the stray capacitance present at each amplifier's summing junction from limiting its performance, the feedback resistors should be 1 k. Since the summing junction capacitance may cause peaking, a small capacitor (1 pF-5 pF) may be paralleled with Rf to neutralize this effect. Finally, sockets should be avoided, because of their tendency to increase interlead capacitance.
Power Supply Bypassing
OUTPUT -IN
Proper power supply decoupling is critical to preserve the integrity of high frequency signals. In carefully laid out designs, decoupling capacitors should be placed in close proximity to the supply pins, while their lead lengths should be kept to a minimum. These measures greatly reduce undesired inductive effects on the amplifier's response. Though two 0.1 F capacitors will typically be effective in decoupling the supplies, several capacitors of different values can be paralleled to cover a wider frequency range.
+IN
-VS
PARALLEL AMPS PROVIDE 100 mA TO LOAD
Figure 40. AD828 Simplified Schematic
INPUT CONSIDERATIONS
An input protection resistor (RIN in Figure 34) is required in circuits where the input to the AD828 will be subjected to transient or continuous overload voltages exceeding the 6 V maximum differential limit. This resistor provides protection for the input transistors by limiting their maximum base current. For high performance circuits, it is recommended that a "balancing" resistor be used to reduce the offset errors caused by bias current flowing through the input and feedback resistors. The balancing resistor equals the parallel combination of RIN and RF and thus provides a matched impedance at each input terminal. The offset voltage error will then be reduced by more than an order of magnitude.
APPLYING THE AD828
By taking advantage of the superior matching characteristics of the AD828, enhanced performance can easily be achieved by employing the circuit in Figure 41. Here, two identical cells are paralleled to obtain even higher load driving capability than that of a single amplifier (100 mA min guaranteed). R1 and R2 are included to limit current flow between amplifier outputs that would arise in the presence of any residual mismatch.
1k +VS 1F 0.1 F 1k 2 8 R1 5 1
1/2 AD828
3 VIN 5 1k 6
VOUT R2 5 7 0.1 F 1F RL
The AD828 is a breakthrough dual amp that delivers precision and speed at low cost with low power consumption. The AD828 offers excellent static and dynamic matching characteristics, combined with the ability to drive heavy resistive loads. As with all high frequency circuits, care should be taken to maintain overall device performance as well as their matching. The following items are presented as general design considerations.
1/2 AD828
4
1k
-VS
Figure 41. Parallel Amp Configuration
-10-
REV. B
AD828
AIN 510 2 510 510 536 100FT RG59A/U RZ = 75 510 510 536 3 RZ 1 RZ 1 3 BIN 510 2
1/2 AD828
1/2 AD828
6 BOUT 7
6
1/2 AD828
5 5
1/2 AD828
7
AOUT
Figure 42. Bidirectional Transmission CKT
Full-Duplex Transmission
Superior load handling capability (50 mA min/amp), high bandwidth, wide supply voltage range and excellent crosstalk rejection makes the AD828 an ideal choice even for the most demanding high speed transmission applications. The schematic below shows a pair of AD828s configured to drive 100 feet of coaxial cable in a full-duplex fashion. Two different NTSC video signals are simultaneously applied at AIN and BIN and are recovered at AOUT and BOUT, respectively. This situation is illustrated in Figures 43 and 44. These pictures
clearly show that each input signal appears undisturbed at its output, while the unwanted signal is eliminated at either receiver. The transmitters operate as followers, while the receivers' gain is chosen to take full advantage of the AD828's unparalleled CMRR. (In practice this gain is adjusted slightly from its theoretical value to compensate for cable nonidealities and losses.) RZ is chosen to match the characteristic impedance of the cable employed. Finally, although a coaxial cable was used, the same topology applies unmodified to a variety of cables (such, as twisted pairs often used in telephony).
500mV
100
500mV
100
AIN
90
BIN
90
BOUT
10 0%
AOUT
10 0%
500mV
10s
500mV
10s
Figure 43. A Transmission/B Reception
Figure 44. B Transmission/A Reception
+15V
A High Performance Video Line Driver
The buffer circuit shown in Figure 45 will drive a backterminated 75 video line to standard video levels (1 V p-p) with 0.1 dB gain flatness to 40 MHz with only 0.05 and 0.01% differential phase and gain at the 3.58 MHz NTSC subcarrier frequency. This level of performance, which meets the requirements for high-definition video displays and test equipment, is achieved using only 7 mA quiescent current/amplifier.
0.1 F VIN RT 75 2 8
1.0 F 75
1/2 AD828
3 4
1 RBT 75 RT 75
-15V 1k 1k
0.1 F
1.0 F
Figure 45. Video Line Driver
REV. B
-11-
AD828
LOW DISTORTION LINE DRIVER
The AD828 can quickly be turned into a powerful, low distortion line driver (see Figure 46). In this arrangement the AD828 can comfortably drive a 75 back-terminated cable, with a 5 MHz, 2 V p-p input; all of this while achieving the harmonic distortion performance outlined in the following table. Configuration 1. No Load 2. 150 RL Only 3. 150 RL 7.5 RC 2nd Harmonic -78.5 dBm -63.8 dBm -70.4 dBm
1.1k +VS 1k 1F 0.1 F 3 1/2 8
AD828
2 1k 1k
1 RC 7.5
In this application one half of the AD828 operates at a gain of 2.1 and supplies the current to the load, while the other provides the overall system gain of 2. This is important for two reasons: the first is to keep the bandwidth of both amplifiers the same, and the second is to preserve the AD828's ability to operate from low supply voltage. RC varies with the load and must be chosen to satisfy the following equation: RC = MRL, where M is defined by [(M + 1) GS = GD] and GD = Driver's Gain, GS = System Gain.
6 VIN 5 75 1/2
75 7 1F 0.1 F
RL
AD828
4
75
-VS
Figure 46. Low Distortion Amplifier
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
8-Lead Plastic Mini-DIP (N) Package
8-Lead SO (R) Package
0.1968 (5.00) 0.1890 (4.80)
8 PIN 1 1
5
0.25 (6.35)
0.31 (7.87)
8
5 4
4 0.30 (7.62) REF 0.035 0.01 (0.89 0.25)
0.1574 (4.00) 0.1497 (3.80) PIN 1
1
0.2440 (6.20) 0.2284 (5.80)
0.39 (9.91) MAX 0.165 0.01 (4.19 0.25) 0.125 (3.18) MIN 0.018 0.003 0.10 (0.46 0.08) (2.54) BSC 0.033 (0.84) NOM
0.0500 (1.27) BSC 0.0098 (0.25) 0.0040 (0.10) SEATING PLANE 0.0688 (1.75) 0.0532 (1.35) 0.0192 (0.49) 0.0138 (0.35) 8 0.0098 (0.25) 0 0.0075 (0.19)
0.0196 (0.50) 0.0099 (0.25)
45
0.18 0.03 (4.57 0.76)
0.011 0.003 (0.28 0.08) 15
0.0500 (1.27) 0.0160 (0.41)
SEATING PLANE
0
-12-
REV. B
PRINTED IN U.S.A.
C1823a-0-6/00 (rev. B) 00879

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