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High Speed, G = +2, Low Cost, Triple Op Amp ADA4862-3
FEATURES
Ideal for RGB/HD/SD video Supports 1080i/720p resolution High speed -3 dB bandwidth: 300 MHz Slew rate: 750 V/s Settling time: 9 ns ( 0.5%) 0.1 dB flatness: 65 MHz Differential gain: 0.02% Differential phase: 0.03 Wide supply range: 5 V to 12 V Low power: 5.3 mA/amp Low voltage offset (RTO): 3.5 mV (typ) High output current: 25 mA Also configurable for gains of +1, -1 Power-down
PIN CONFIGURATION
POWER DOWN 1 POWER DOWN 2 POWER DOWN 3 +VS +IN 1 -IN 1 VOUT1
1
550
14
VOUT2 -IN 2 +IN 2 -VS +IN 3 -IN 3 VOUT3
05600-001
2
550
13
3
12
4
ADA4862-3
11
5
10
550
6
550
9
7
550
550
8
Figure 1. 14-Lead SOIC (R-14)
APPLICATIONS
Consumer video Professional video Filter buffers
GENERAL DESCRIPTION
The ADA4862-3 (triple) is a low cost, high speed, internally fixed, G = +2 op amp, which provides excellent overall performance for high definition and RGB video applications. The 300 MHz, G = +2, -3 dB bandwidth, and 750 V/s slew rate make this amplifier well suited for many high speed applications. The ADA4862-3 can also be configured to operate in gains of G = +1 and G = -1. With its combination of low price, excellent differential gain (0.02%), differential phase (0.03), and 0.1 dB flatness out to 65 MHz, this amplifier is ideal for both consumer and professional video applications. The ADA4862-3 is designed to operate on supply voltages as low as +5 V and up to 5 V using only 5.3 mA/amp of supply current. To further reduce power consumption, each amplifier is equipped with a power-down feature that lowers the supply current to 200 A/amp. The ADA4862-3 also consumes less board area because feedback and gain set resistors are on-chip. Having the resistors on chip simplifies layout and minimizes the required board space. The ADA4862-3 is available in a 14-lead SOIC package and is designed to work in the extended temperature range of -40C to +105C.
6.1 6.0 5.9 VS = +5V G = +2 RL = 150 CL = 4pF VOUT = 2V p-p VS = 5V
CLOSED-LOOP GAIN (dB)
5.8 5.7 5.6 5.5 5.4 5.3 5.2 5.1 0.1
1
10 FREQUENCY (MHz)
100
1000
Figure 2. Large Signal 0.1 dB Bandwidth for Various Supplies
Rev. A
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 that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 (c) 2005 Analog Devices, Inc. All rights reserved.
05600-022
ADA4862-3 TABLE OF CONTENTS
Features .............................................................................................. 1 Applications....................................................................................... 1 Pin Configuration............................................................................. 1 General Description ......................................................................... 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Absolute Maximum Ratings............................................................ 5 Thermal Resistance ...................................................................... 5 ESD Caution.................................................................................. 5 Typical Performance Characteristics ............................................. 6 Applications..................................................................................... 11 Using the ADA4862-3 in Gains = +1, -1................................ 11 Video Line Driver....................................................................... 13 Single-Supply Operation ........................................................... 13 Power Down................................................................................ 13 Layout Considerations............................................................... 14 Power Supply Bypassing ............................................................ 14 Outline Dimensions ....................................................................... 15 Ordering Guide .......................................................................... 15
REVISION HISTORY
8/05--Rev. 0 to Rev. A Changes to Ordering Guide .......................................................... 15
7/05--Revision 0: Initial Version
Rev. A | Page 2 of 16
ADA4862-3 SPECIFICATIONS
VS = +5 V (@TA = 25oC, G = +2, RL = 150 , unless otherwise noted). Table 1.
Parameter DYNAMIC PERFORMANCE -3 dB Bandwidth G = +1 Bandwidth for 0.1 dB Flatness +Slew Rate (Rising Edge) -Slew Rate (Falling Edge) Settling Time to 0.5% DISTORTION/NOISE PERFORMANCE Harmonic Distortion HD2 Harmonic Distortion HD3 Harmonic Distortion HD2 Harmonic Distortion HD3 Voltage Noise (RTO) Current Noise (RTI) Differential Gain Differential Phase Crosstalk DC PERFORMANCE Offset Voltage (RTO) +Input Bias Current Gain Accuracy INPUT CHARACTERISTICS Input Resistance Input Capacitance Input Common-Mode Voltage Range POWER DOWN PIN Input Voltage Bias Current Turn-On Time Turn-Off Time OUTPUT CHARACTERISTICS Output Overdrive Recovery Time (Rise/Fall) Output Voltage Swing Output Voltage Swing Short-Circuit Current POWER SUPPLY Operating Range Total Quiescent Current Quiescent Current /Amplifier Power Supply Rejection Ratio (RTO) +PSR -PSR Conditions VO = 0.2 V p-p VO = 2 V p-p VO = 0.2 V p-p VO = 2 V p-p VO = 2 V p-p VO = 2 V p-p VO = 2 V step fC = 1 MHz, VO = 2 V p-p fC = 1 MHz, VO = 2 V p-p fC = 5 MHz, VO = 2 V p-p fC = 5 MHz, VO = 2 V p-p f = 100 kHz f = 100 kHz, +IN Min Typ 300 200 620 65 750 600 9 -81 -88 -68 -76 10.6 1.4 0.02 0.03 -75 Max Unit MHz MHz MHz MHz V/s V/s ns dBc dBc dBc dBc nV/Hz pA/Hz % Degrees dB
Amplifier 1 driven, Amplifier 2 output measured, f = 1 MHz Referred to output (RTO) -25 -2.5 1.9
+3.5 -0.6 2 13 2 1 to 4 0.6 1.8 -3 115 3.5 200 85/50 1.2 to 3.8 1 to 4 65
+25 +1 2.1
mV A V/V M pF V V V A A s ns ns V V mA
+IN +IN G = +1 Enabled Power down Enabled Power down
VIN = +2.25 V to -0.25 V RL = 150 RL = 1 k Sinking or sourcing 5 14
Enabled Power down = +VS +VS = 2 V to 3 V, -VS = -2.5 V +VS = 2.5 V, -VS = -2 V to -3 V Power Down pin = -VS
16 0.2 -55 -52
12 18 0.33
-52 -49
V mA mA dB dB dB
Rev. A | Page 3 of 16
ADA4862-3
VS = 5 V (@TA = +25oC, G = +2, RL = 150 , unless otherwise noted). Table 2.
Parameter DYNAMIC PERFORMANCE -3 dB Bandwidth G = +1 Bandwidth for 0.1 dB Flatness +Slew Rate (Rising Edge) -Slew Rate (Falling Edge) Settling Time to 0.5% DISTORTION/NOISE PERFORMANCE Harmonic Distortion HD2 Harmonic Distortion HD3 Harmonic Distortion HD2 Harmonic Distortion HD3 Voltage Noise (RTO) Current Noise (RTI) Differential Gain Differential Phase Crosstalk DC PERFORMANCE Offset Voltage (RTO) +Input Bias Current Gain Accuracy INPUT CHARACTERISTICS Input Resistance Input Capacitance Input Common-Mode Voltage Range POWER DOWN PIN Input Voltage Bias Current Turn-On Time Turn-Off Time OUTPUT CHARACTERISTICS Output Overdrive Recovery Time (Rise/Fall) Output Voltage Swing Output Voltage Swing Short-Circuit Current POWER SUPPLY Operating Range Total Quiescent Current Quiescent Current/Amplifier Power Supply Rejection Ratio (RTO) +PSR -PSR Conditions VO = 0.2 V p-p VO = 2 V p-p VO = 0.2 V p-p VO = 2 V p-p VO = 2 V p-p VO = 2 V p-p VO = 2 V step fC = 1 MHz, VO = 2 V p-p fC = 1 MHz, VO = 2 V p-p fC = 5 MHz, VO = 2 V p-p fC = 5 MHz, VO = 2 V p-p f = 100 kHz f = 100 kHz, +IN Min Typ 310 260 720 54 1050 830 9 -87 -100 -74 -90 10.6 1.4 0.01 0.02 -75 Max Unit MHz MHz MHz MHz V/s V/s ns dBc dBc dBc dBc nV/Hz pA/Hz % Degrees dB
Amplifier 1 driven, Amplifier 2 output measured, f = 1 MHz -25 -2.5 1.9 +IN +IN G = +1 Enabled Power down Enabled Power down
+2 -0.6 2 14 2 -3.7 to +3.8 -4.4 -3.2 -3 250 3.5 200 85/40 -3.5 to +3.5 -3.9 to +3.9 115
+25 +1 2.1
mV A V/V M pF V V V A A s ns ns V V mA
VIN = 3.0 V RL = 150 RL = 1 k Sinking or sourcing 5 14.5
Enabled Power down = +VS +VS = 4 V to 6 V, -VS = -5 V +VS = 5 V, -VS = -4 V to -6 V, Power Down pin = -VS
17.9 0.3 -57 -54
12 20.5 0.5
-54 +50.5
V mA mA dB dB dB
Rev. A | Page 4 of 16
ADA4862-3 ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter Supply Voltage Power Dissipation Common-Mode Input Voltage Storage Temperature Operating Temperature Range Lead Temperature Junction Temperature Rating 12.6 V See Figure 3 VS -65C to +125C -40C to +105C JEDEC J-STD-20 150C
The power dissipated in the package (PD) is the sum of the quiescent power dissipation and the power dissipated in the die due to the amplifier's drive at the output. The quiescent power is the voltage between the supply pins (VS) x the quiescent current (IS). PD = Quiescent Power + (Total Drive Power - Load Power)
V V V 2 PD = (VS x I S ) + S x OUT - OUT RL RL 2 RMS output voltages should be considered. Airflow increases heat dissipation, effectively reducing JA. In addition, more metal directly in contact with the package leads and through holes under the device reduces JA. Figure 3 shows the maximum safe power dissipation in the package vs. the ambient temperature for the 14-lead SOIC (90C/W) on a JEDEC standard 4-layer board. JA values are approximations.
2.5
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.
THERMAL RESISTANCE
JA is specified for the worst-case conditions, that is, JA is specified for device soldered in circuit board for surface-mount packages. Table 4. Thermal Resistance
Package Type 14-lead SOIC JA 90 Unit C/W
MAXIMUM POWER DISSIPATION (W)
2.0
1.5
Maximum Power Dissipation
The maximum safe power dissipation for the ADA4862-3 is limited by the associated rise in junction temperature (TJ) on the die. At approximately 150C, which is the glass transition temperature, the plastic changes its properties. Even temporarily exceeding this temperature limit may change the stresses that the package exerts on the die, permanently shifting the parametric performance of the amplifiers. Exceeding a junction temperature of 150C for an extended period can result in changes in silicon devices, potentially causing degradation or loss of functionality.
1.0
0.5
05600-036
0
-55 -45 -35 -25 -15 -5 5 15 25 35 45 55 65 75 85 95 105 115 125
AMBIENT TEMPERATURE (C)
Figure 3. Maximum Power Dissipation vs. Temperature for a 4-Layer Board
ESD 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 this product 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.
Rev. A | Page 5 of 16
ADA4862-3 TYPICAL PERFORMANCE CHARACTERISTICS
8 7 G = +2 RL = 150 CL = 4pF VOUT = 0.2V p-p
200 2.7
VS = +5V
VS = +5V 100 VS = 5V 2.6
CLOSED-LOOP GAIN (dB)
6
OUTPUT VOLTAGE (mV) VS = 5V
5 4 3 2
VS = 5V
0
2.5
-100
05600-004
1 0 0.1
1
10 FREQUENCY (MHz)
100
1000
-200
2.3
Figure 4. Small Signal Frequency Response for Various Supplies
8 7 G = +2 RL = 150 CL = 4pF VOUT = 2V p-p VS = 5V
Figure 7. Small Signal Transient Response for Various Supplies
200 150 100
OUTPUT VOLTAGE (V)
CLOSED-LOOP GAIN (dB)
6 5 VS = +5V 4 3 2
CL = 9pF
CL = 4pF 50 0 -50 -100 G = +2 RL = 150 CL = 4pF VOUT = 0.2V p-p VS = 5V TIME = 5ns/DIV CL = 6pF
05600-012
1 0 0.1
1
10 FREQUENCY (MHz)
100
1000
-200
Figure 5. Large Signal Frequency Response for Various Supplies
6.1 6.0 5.9 VS = +5V G = +2 RL = 150 CL = 4pF VOUT = 2V p-p VS = 5V
Figure 8. Small Signal Transient Response for Various Capacitor Loads
2.7 CL = 9pF CL = 6pF 2.6
OUTPUT VOLTAGE (V)
CLOSED-LOOP GAIN (dB)
5.8 5.7 5.6 5.5 5.4 5.3 5.2 5.1 0.1
CL = 4pF 2.5
2.4
05600-022
1
10 FREQUENCY (MHz)
100
1000
2.3
Figure 6. Large Signal 0.1 dB Bandwidth for Various Supplies
Figure 9. Small Signal Transient Response for Various Capacitor Loads
Rev. A | Page 6 of 16
05600-014
G = +2 RL = 150 VOUT = 0.2V p-p VS = 5V TIME = 5ns/DIV
05600-016
-150
05600-028
G = +2 RL = 150 CL = 4pF VOUT = 0.2V p-p TIME = 5ns/DIV
2.4
OUTPUT VOLTAGE (V) +VS = 5V, -VS = 0V
ADA4862-3
6
1.5
4.0
OUTPUT AND INPUT VOLTAGE (V)
5 4 3 2 1 0 -1 -2 -3 -4 -5
05600-010
INPUT VOLTAGE x 2
1.0
OUTPUT VOLTAGE (V) VS = 5V
3.5
OUTPUT VOLTAGE (V) +VS = 5V, -VS = 0V
VS = 5V G = +2 RL = 150 CL = 4pF f = 1MHz
VOUT
VS = +5V 0.5 VS = 5V 0 2.5 3.0
-0.5 G = +2 RL = 150 CL = 4pF VOUT = 2V p-p TIME = 5ns/DIV
2.0
-1.0
1.5
-6 0 100 200 300 400 500 600 700 800 900 TIME (ns)
1000
-1.5
1.0
Figure 10. Large Signal Transient Response for Various Supplies
5.5
Figure 13. Input Overdrive Recovery
1.5
OUTPUT AND INPUT VOLTAGE (V)
5.0
CL = 9pF CL = 6pF 1.0
OUTPUT VOLTAGE (V)
INPUT VOLTAGE x 2
4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 VOUT
VS = 5V G = +2 RL = 150 CL = 4pF f = 1MHz
CL = 4pF 0.5
0
-0.5
-1.0
05600-018
G = +2 RL = 150 CL = 4pF VOUT = 2V p-p VS = 5V TIME = 5ns/DIV
-0.5 0 100 200 300 400 500 600 700 800 900 TIME (ns)
1000
-1.5
Figure 11. Large Signal Transient Response for Various Capacitor Loads
Figure 14. Output Overdrive Recovery
4.0 CL = 9pF CL = 6pF 3.5
OUTPUT VOLTAGE (V)
CL = 4pF 3.0
2.5
2.0
1.5
1.0
Figure 12. Large Signal Transient Response for Various Capacitor Loads
05600-019
G = +2 RL = 150 CL = 4pF VOUT = 2V p-p VS = 5V TIME = 5ns/DIV
Rev. A | Page 7 of 16
05600-041
05600-042
ADA4862-3
1.5 20 VS = 5V, +5V G = +2 VOUT = 2V p-p RL =150 CL = 4pF VOUT EXPANDED 15
1.0 1.5 VOUT 20 15 10 5 0 -5 VS = 5V, +5V G = +2 VOUT = 2V p-p RL = 150 CL = 4pF 35 40 45 -10 -15 -20 50
05600-046 05600-023 05600-006
1.0 VOUT
VOUT AND VIN (V)
10
VOUT EXPANDED (mV)
VIN 0
5 0 -5
VOUT AND VIN (V)
0.5
0.5
0
-0.5 -10 -1.0
-0.5
VOUT EXPANDED
-1.0
-15
05600-043
-1.5 0 5 10 15 20 25 TIME (ns) 30 35 40 45
-20 50
-1.5 0 5 10 15 20 25 TIME (ns) 30
Figure 15. Settling Time Falling Edge
1600 1400 1200 G = +2 VS = 5V RL = 150 CL = 4pF POSITIVE SLEW RATE
800 700 600
Figure 18. Settling Time Rising Edge
G = +2 VS = 5V RL = 150 CL = 4pF
POSITIVE SLEW RATE
SLEW RATE (V/s)
SLEW RATE (V/s)
NEGATIVE SLEW RATE 500 400 300 200
1000 NEGATIVE SLEW RATE 800 600 400
05600-005
200 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 OUTPUT VOLTAGE STEP (V p-p)
100 0 0 0.5 1.0 1.5 2.0 2.5 3.0 OUTPUT VOLTAGE STEP (V p-p)
Figure 16. Slew Rate vs. Output Voltage
100 G = +2 RL = 150 CL = 4pF VOUT = 2V p-p VS = 5V VS = +5V
CROSSTALK (dB)
0
Figure 19. Slew Rate vs. Output Voltage
-20
VOLTAGE NOISE (nV/ Hz)
G = +2 RL = 150 CL = 4pF VOUT = 2V p-p VS = 5V VS = +5V
-40
10
-60
-80
-100
05600-037
1 10
100
1k
10k
100k
1M
10M
100M
-120 0.1
1
10 FREQUENCY (MHz)
100
1000
FREQUENCY (Hz)
Figure 17. Voltage Noise vs. Frequency Referred to Output (RTO)
Figure 20. Large Signal Crosstalk
Rev. A | Page 8 of 16
VOUT EXPANDED (mV)
VIN
ADA4862-3
19
0 VS = 5V
18
POWER SUPPLY REJECTION (dB)
-10
TOTAL SUPPLY CURRENT (mA)
-20
-30 -PSR -40 +PSR -50
17
16
05600-026
15 4 5 6 7 8 9 10 11 12 SUPPLY VOLTAGE (V)
-70 0.01
0.1
1
10
100
1000
FREQUENCY (MHz)
Figure 21. Total Supply Current vs. VSUPPLY
20 19
0
Figure 23. Power Supply Rejection vs. Frequency
VS = 2.5V
TOTAL SUPPLY CURRENT (mA)
18 17
VS = 5V
POWER SUPPLY REJECTION (dB)
-10
-20 -PSR -30 +PSR
VS = +5V 16 15 14
05600-021
-40
-50
05600-052
13 12 -40
-25
-10
5
20
35
50
65
80
95
110
125
-60 0.01
0.1
1
10
100
1000
TEMPERATURE (C)
FREQUENCY (MHz)
Figure 22. Total Supply Current at Various Supplies vs. Temperature
Figure 24. Power Supply Rejection vs. Frequency
Rev. A | Page 9 of 16
05600-051
-60
ADA4862-3
-50 G = +2 RL = 150 CL = 4pF HD2 VS = 5V fO = 20MHz fO = 10MHz -60 -70 -50 G = +2 RL = 150 CL = 4pF HD3 VS = 5V fO = 10MHz fO = 20MHz
-60
DISTORTION (dBc)
-70 fO = 5MHz -80
DISTORTION (dBc)
-80 -90 -100 -110 fO = 2MHz
05600-054
-90
fO = 2MHz fO = 1MHz
fO = 5MHz
-100
05600-049
-120 -130 0 1
fO = 1MHz
-110 0 1 2 OUTPUT VOLTAGE (V p-p) 3 4
2 OUTPUT VOLTAGE (V p-p)
3
4
Figure 25. HD2 vs. Frequency vs. Output Voltage
-50 G = +2 RL = 150 CL = 4pF HD2 VS = 5V fO = 20MHz fO = 10MHz -60 -50
Figure 27. HD3 vs. Frequency vs. Output Voltage
-60
fO = 20MHz -70 fO = 10MHz
DISTORTION (dBc)
-70 fO = 5MHz -80
DISTORTION (dBc)
-80 -90 -100 -110 fO = 5MHz fO = 2MHz fO = 1MHz G = +2 RL = 150 CL = 4pF HD3 VS = +5V 2.0 2.5
-90 fO = 2MHz -100 fO = 1MHz
05600-050
-110 0 0.5 1.0 1.5 2.0 2.5 OUTPUT VOLTAGE (V p-p)
-130 0 0.5 1.0 1.5 OUTPUT VOLTAGE (V p-p)
Figure 26. HD2 vs. Frequency vs. Output Voltage
Figure 28. HD3 vs. Frequency vs. Output Voltage
Rev. A | Page 10 of 16
05600-048
-120
ADA4862-3 APPLICATIONS
USING THE ADA4862-3 IN GAINS = +1, -1
CLOSED-LOOP GAIN (dB)
4 3 2 1 VS = 5V 0 -1 -2
05600-053
The ADA4862-3 was designed to offer outstanding video performance, simplify applications, and minimize board area. The ADA4862-3 is a triple amplifier with on-chip feedback and gain set resistors. The gain is fixed internally at G = +2. The inclusion of the on-chip resistors not only simplifies the design of the application but also eliminates six surface-mount resistors, saving valuable board space and lowers assembly costs. A typical schematic is shown in Figure 29.
+VS 10F
G = +1 RL = 150 CL = 4pF VOUT = 200mV p-p
VS = +5V
-3 -4 0.1
1
10 FREQUENCY (MHz)
100
1000
0.01F
Figure 31. Small Signal Unity Gain
3
VIN RT 0.01F
VOUT
2 1 0 -1
G = +1 RL = 150 CL = 4pF VOUT = 2V p-p
10F -VS
05600-029
CLOSED-LOOP GAIN (dB)
VS = 5V
VS = +5V -2 -3 -4
GAIN OF +2
Figure 29. Noninverting Configuration (G = +2)
While the ADA4862-3 has a fixed gain of G = +2, it can be used in other gain configurations, such as G = -1 and G = +1, which are discussed next.
-5 -6 0.1
1
10 FREQUENCY (MHz)
100
1000
Unity-Gain Operation (Option 1)
There are two options for obtaining unity gain (G = +1). The first is shown in Figure 30. In this configuration, the -IN input pin is left floating (feedback is provided via the internal 550 ), and the input is applied to the noninverting input. The noise gain for this configuration is 1. Frequency performance and transient response are shown in Figure 31 through Figure 33.
+VS 10F
2.0
Figure 32. Large Signal Gain +1
CL = 9pF 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 G = +1 RL = 150 VOUT = 2V p-p VS = 5V TIME = 5ns/DIV CL = 6pF CL = 4pF
0.01F
OUTPUT VOLTAGE (V)
VIN RT 0.01F
VOUT
-2.0
Figure 33. Large Signal Transient Response for Various Capacitor Loads
10F -VS GAIN OF +1
05600-032
Figure 30. Unity Gain of Option 1
Rev. A | Page 11 of 16
05600-020
05600-002
ADA4862-3
Option 2
Another option exists for running the ADA4862-3 as a unitygain amplifier. In this configuration, the noise gain is 2, see Figure 34. The frequency response and transient response for this configuration closely match the gain of +2 plots because the noise gains are equal. This method does have twice the noise gain of Option 1; however, in applications that do not require low noise, Option 2 offers less peaking and ringing. By tying the inputs together, the net gain of the amplifier becomes 1. Equation 1 shows the transfer characteristic for the schematic shown in Figure 34. Frequency and transient response are shown in Figure 35 and Figure 36.
- RF VO = V i R G R + RG +Vi F R G
200 150 100 50 0 -50 -100
05600-039
G = +1 VS = 5V RL = 150 TIME = 2ns/DIV
OUTPUT VOLTAGE (mV)
-150 -200
(1)
Figure 36. Small Signals Transient Response of Option 2
+VS 10F
which simplifies to VO = Vi.
+VS 10F
VIN RT
0.01F
0.01F RF RG VIN RT 0.01F VOUT
VOUT
0.01F
10F -VS GAIN OF -1
05600-031
10F -VS GAIN OF +1
05600-030
Figure 37. Inverting Configuration (G = -1)
2.0 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 -2.0 G = -1 RL = 150 VOUT = 2V p-p VS = 5V TIME = 5ns/DIV CL = 4pF CL = 9pF CL = 6pF
Figure 34. Unity Gain of Option 2
OUTPUT VOLTAGE (V)
1 0 -1 -2 G = +1 RL = 150
GAIN (dB)
-3 -4 -5
05600-027
-6 -7 0.1
Figure 38. Large Signal Transient Response for Various Capacitor Loads
1
10 FREQUENCY (MHz)
100
1000
Figure 35. Frequency Response of Option 2
Rev. A | Page 12 of 16
05600-017
ADA4862-3
VIDEO LINE DRIVER
The ADA4862-3 was designed to excel in video driver applications. Figure 39 shows a typical schematic for a video driver operating on a bipolar supplies.
+VS 10F
SINGLE-SUPPLY OPERATION
The ADA4862-3 can also operate in single-supply applications. Figure 42 shows the schematic for a single 5 V supply video driver. Resistors R2 and R4 establish the midsupply reference. Capacitor C2 is the bypass capacitor for the midsupply reference. Capacitor C1 is the input coupling capacitor, and C6 is the output coupling capacitor. Capacitor C5 prevents constant current from being drawn through the internal gain set resistor. Resistor R3 sets the circuits ac input impedance. For more information on single-supply operation of op amps, see www.analog.com/library/analogDialogue/archives/3502/avoiding/.
05600-033
0.1F
-
ADA4862-3
+
75 CABLE VIN 75 -VS 0.1F
75
75 CABLE VOUT 75
10F
+5V C2 1F C3 2.2F
Figure 39. Video Driver Schematic
In applications that require two video loads be driven simultaneously, the ADA4862-3 can deliver. Figure 40 shows the ADA4862-3 configured with dual video loads. Figure 41 shows the dual video load performance.
+VS 10F 75 75 CABLE VOUT1 0.1F
2
+5V
R2 50k R3 1k
R4 50k
C4 0.01F
VIN R1 50 C1 22F
C6 220F R5 75 VOUT R6 75
75 75 CABLE VOUT2 75
ADA4862-3
-VS
05600-035
-
7
C5 22F
75
8 6
1
+
Figure 42. Single-Supply Video Driver Schematic
0.1F 75 CABLE VIN 75
05600-034
POWER DOWN
The ADA4862-3 is equipped with an independent Power Down pin for each amplifier allowing the user to reduce the supply current when an amplifier is inactive. The voltage applied to the -VS pin is the logic reference, making single-supply applications useful with conventional logic levels. In a typical 5 V singlesupply application, the -VS pin is connected to analog ground. The amplifiers are powered down when applied logic levels are greater than -VS + 1 V. The amplifiers are enabled whenever the disable pins are left either floating (disconnected) or the applied logic levels are lower than 1 V above -VS.
-VS
10F
Figure 40. Video Driver Schematic for Two Video Loads
8 7
CLOSED-LOOP GAIN (dB)
G = +2 RL = 75 CL = 4pF VOUT = 2V p-p
6 5 VS = +5V 4 3 2
VS = 5V
0 0.1
1
10 FREQUENCY (MHz)
100
1000
Figure 41. Large Signal Frequency Response for Various Supplies, RL = 75
05600-008
1
Rev. A | Page 13 of 16
ADA4862-3
LAYOUT CONSIDERATIONS
As is the case with all high speed applications, careful attention to printed circuit board layout details prevents associated board parasitics from becoming problematic. Proper RF design technique is mandatory. The PCB should have a ground plane covering all unused portions of the component side of the board to provide a low impedance return path. Removing the ground plane on all layers from the area near the input and output pins reduces stray capacitance. Termination resistors and loads should be located as close as possible to their respective inputs and outputs. Input and output traces should be kept as far apart as possible to minimize coupling (crosstalk) though the board. Adherence to microstrip or stripline design techniques for long signal traces (greater than about 1 inch) is recommended.
POWER SUPPLY BYPASSING
Careful attention must be paid to bypassing the power supply pins of the ADA4862-3. High quality capacitors with low equivalent series resistance (ESR), such as multilayer ceramic capacitors (MLCCs), should be used to minimize supply voltage ripple and power dissipation. A large, usually tantalum, 10 F to 47 F capacitor located in proximity to the ADA4862-3 is required to provide good decoupling for lower frequency signals. In addition, 0.1 F MLCC decoupling capacitors should be located as close to each of the power supply pins as is physically possible, no more than 1/8 inch away. The ground returns should terminate immediately into the ground plane. Locating the bypass capacitor return close to the load return minimizes ground loops and improves performance.
Rev. A | Page 14 of 16
ADA4862-3 OUTLINE DIMENSIONS
8.75 (0.3445) 8.55 (0.3366)
14 1 8 7
4.00 (0.1575) 3.80 (0.1496)
6.20 (0.2441) 5.80 (0.2283)
0.25 (0.0098) 0.10 (0.0039)
1.27 (0.0500) BSC
1.75 (0.0689) 1.35 (0.0531)
0.50 (0.0197) x 45 0.25 (0.0098)
COPLANARITY 0.10
0.51 (0.0201) 0.31 (0.0122)
SEATING PLANE
8 0.25 (0.0098) 0 1.27 (0.0500) 0.40 (0.0157) 0.17 (0.0067)
COMPLIANT TO JEDEC STANDARDS MS-012-AB CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN
Figure 43. 14-Lead Standard Small Outline Package [SOIC_N] Narrow Body (R-14) Dimensions shown in millimeters and (inches)
ORDERING GUIDE
Model ADA4862-3YRZ 1 ADA4862-3YRZ-RL1 ADA4862-3YRZ-RL71
1
Temperature Range -40C to +105C -40C to +105C -40C to +105C
Package Description 14-Lead SOIC_N 14-Lead SOIC_N 14-Lead SOIC_N
Ordering Quantity 1 2,500 1,000
Package Option R-14 R-14 R-14
Z = Pb-free part.
Rev. A | Page 15 of 16
ADA4862-3 NOTES
(c) 2005 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D05600-0-8/05(A)
Rev. A | Page 16 of 16

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