AD ADA4861-3 High speed, low cost, triple op amp Datasheet

High Speed, Low Cost,
Triple Op Amp
ADA4861-3
PIN CONFIGURATION
High speed
730 MHz, −3 dB bandwidth
625 V/μs slew rate
13 ns settling time to 0.5%
Wide supply range: 5 V to 12 V
Low power: 6 mA/amplifier
0.1 dB flatness: 100 MHz
Differential gain: 0.01%
Differential phase: 0.02°
Low voltage offset: 100 μV (typical)
High output current: 25 mA
Power down
POWER DOWN 1 1
14 OUT 2
POWER DOWN 2 2
13 –IN 2
POWER DOWN 3 3
+VS 4
12 +IN 2
ADA4861-3
11 –VS
+IN 1 5
10 +IN 3
–IN 1 6
9
–IN 3
OUT 1 7
8
OUT 3
05708-001
FEATURES
Figure 1.
APPLICATIONS
Consumer video
Professional video
Broadband video
ADC buffers
Active filters
GENERAL DESCRIPTION
The ADA4861-3 is available in a 14-lead SOIC_N package and
is designed to work over the extended temperature range of
−40°C to +105°C.
G = +2
VOUT = 2V p-p
RF = RG = 301Ω
6.0
5.9
5.8
VS = ±5V
5.7
VS = +5V
5.6
5.5
5.4
5.3
05708-011
The ADA4861-3 is designed to operate on supply voltages as
low as +5 V and up to ±5 V using only 6 mA/amplifier of supply
current. To further reduce power consumption, each amplifier
is equipped with a power-down feature that lowers the supply
current to 0.3 mA/amplifier when not being used.
6.1
CLOSED-LOOP GAIN (dB)
The ADA4861-3 is a low cost, high speed, current feedback,
triple op amp that provides excellent overall performance. The
730 MHz, −3 dB bandwidth, and 625 V/μs slew rate make this
amplifier well suited for many high speed applications. With its
combination of low price, excellent differential gain (0.01%),
differential phase (0.02°), and 0.1 dB flatness out to 100 MHz,
this amplifier is ideal for both consumer and professional video
applications.
5.2
5.1
0.1
1
10
100
1000
FREQUENCY (MHz)
Figure 2. Large Signal 0.1 dB Flatness
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
©2006 Analog Devices, Inc. All rights reserved.
ADA4861-3
TABLE OF CONTENTS
Features .............................................................................................. 1
Gain Configurations .................................................................. 13
Applications....................................................................................... 1
20 MHz Active Low-Pass Filter ................................................ 13
Pin Configuration............................................................................. 1
RGB Video Driver ...................................................................... 14
General Description ......................................................................... 1
Driving Two Video Loads ......................................................... 14
Revision History ............................................................................... 2
POWER-DOWN Pins ............................................................... 14
Specifications..................................................................................... 3
Single-Supply Operation ........................................................... 15
Absolute Maximum Ratings............................................................ 5
Power Supply Bypassing ............................................................ 15
Thermal Resistance ...................................................................... 5
Layout .......................................................................................... 15
ESD Caution.................................................................................. 5
Outline Dimensions ....................................................................... 16
Typical Performance Characteristics ............................................. 6
Ordering Guide .......................................................................... 16
Applications..................................................................................... 13
REVISION HISTORY
3/06—Rev 0 to Rev. A
Changes to 20 MHz Active Low-Pass Filter Section.................. 13
Changes to Figure 48 and Figure 49............................................. 13
10/05—Revision 0: Initial Version
Rev. A | Page 2 of 16
ADA4861-3
SPECIFICATIONS
VS = +5 V (@ TA = 25°C, G = +2, RL = 150 Ω, CL = 4 pF, unless otherwise noted); for G = +2, RF = RG = 301 Ω; and for G = +1, RF = 499 Ω.
Table 1.
Parameter
DYNAMIC PERFORMANCE
–3 dB Bandwidth
Bandwidth for 0.1 dB Flatness
+Slew Rate (Rising Edge)
−Slew Rate (Falling Edge)
Settling Time to 0.5% (Rise/Fall)
NOISE/DISTORTION PERFORMANCE
Harmonic Distortion HD2/HD3
Harmonic Distortion HD2/HD3
Input Voltage Noise
Input Current Noise
Differential Gain
Differential Phase
All-Hostile Crosstalk
DC PERFORMANCE
Input Offset Voltage
+Input Bias Current
−Input Bias Current
Open-Loop Transresistance
INPUT CHARACTERISTICS
Input Resistance
Input Capacitance
Input Common-Mode Voltage Range
Common-Mode Rejection Ratio
POWER-DOWN PINS
Input Voltage
Bias Current
Turn-On Time
Turn-Off Time
OUTPUT CHARACTERISTICS
Output Overdrive Recovery Time (Rise/Fall)
Output Voltage Swing
Short-Circuit Current
POWER SUPPLY
Operating Range
Total Quiescent Current
Quiescent Current/Amplifier
Power Supply Rejection Ratio
+PSR
Conditions
Min
Typ
Max
Unit
VO = 0.2 V p-p
VO = 2 V p-p
G = +1, 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
350
145
560
85
590
480
12/13
MHz
MHz
MHz
MHz
V/μs
V/μs
ns
fC = 1 MHz, VO = 2 V p-p
fC = 5 MHz, VO = 2 V p-p
f = 100 kHz
f = 100 kHz, +IN/−IN
−81/−89
−69/−76
3.8
1.7/5.5
0.02
0.03
−65
dBc
dBc
nV/√Hz
pA/√Hz
%
Degrees
dB
Amplifier 1 and Amplifier 2 driven,
Amplifier 3 output measured, f = 1 MHz
+IN
−IN
+IN
G = +1
VCM = 2 V to 3 V
−13
−2
−8
400
−0.9
−0.8
+2.3
620
−54
14
85
1.5
1.2 to 3.8
−56.5
MΩ
Ω
pF
V
dB
0.6
1.8
−3
115
200
3.5
V
V
μA
μA
ns
μs
55/100
1.1 to 3.9
0.85 to 4.15
65
ns
V
V
mA
Enabled
Power down
Enabled
Power down
VIN = +2.25 V to −0.25 V
RL = 150 Ω
RL = 1 kΩ
Sinking and sourcing
Enabled
POWER DOWN pins = +VS
+VS = 4 V to 6 V, −VS = 0 V
Rev. A | Page 3 of 16
1.2 to 3.8
0.9 to 4.1
5
12.5
−60
16.1
0.2
−64
+13
+1
+13
12
18.5
0.33
mV
μA
μA
kΩ
V
mA
mA
dB
ADA4861-3
VS = ±5 V (@ TA = 25°C, G = +2, RL = 150 Ω, CL = 4 pF, unless otherwise noted); for G = +2, RF = RG = 301 Ω; and for G = +1, RF = 499 Ω.
Table 2.
Parameter
DYNAMIC PERFORMANCE
–3 dB Bandwidth
Bandwidth for 0.1 dB Flatness
+Slew Rate (Rising Edge)
−Slew Rate (Falling Edge)
Settling Time to 0.5% (Rise/Fall)
NOISE/DISTORTION PERFORMANCE
Harmonic Distortion HD2/HD3
Harmonic Distortion HD2/HD3
Input Voltage Noise
Input Current Noise
Differential Gain
Differential Phase
All-Hostile Crosstalk
DC PERFORMANCE
Input Offset Voltage
+Input Bias Current
−Input Bias Current
Open-Loop Transresistance
INPUT CHARACTERISTICS
Input Resistance
Input Capacitance
Input Common-Mode Voltage Range
Common-Mode Rejection Ratio
POWER-DOWN PINS
Input Voltage
Bias Current
Turn-On Time
Turn-Off Time
OUTPUT CHARACTERISTICS
Output Overdrive Recovery Time (Rise/Fall)
Output Voltage Swing
Short-Circuit Current
POWER SUPPLY
Operating Range
Total Quiescent Current
Quiescent Current/Amplifier
Power Supply Rejection Ratio
+PSR
−PSR
Conditions
Min
Typ
Max
Unit
VO = 0.2 V p-p
VO = 2 V p-p
G = +1, 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
370
210
730
100
910
680
12/13
MHz
MHz
MHz
MHz
V/μs
V/μs
ns
fC = 1 MHz, VO = 2 V p-p
fC = 5 MHz, VO = 2 V p-p
f = 100 kHz
f = 100 kHz, +IN/−IN
−85/−99
−73/−86
3.8
1.7/5.5
0.01
0.02
−65
dBc
dBc
nV/√Hz
pA/√Hz
%
Degrees
dB
Amplifier 1 and Amplifier 2 driven,
Amplifier 3 output measured, f = 1 MHz
+IN
−IN
+IN
G = +1
VCM = ±2 V
−13
−2
−8
500
−0.1
−0.7
+2.9
720
−55
15
90
1.5
−3.7 to +3.7
−58
MΩ
Ω
pF
V
dB
−4.4
−3.2
−3
250
200
3.5
V
V
μA
μA
ns
μs
30/90
−3.1 to +3.65
±4.05
100
ns
V
V
mA
Enabled
Power down
Enabled
Power down
VIN = ±3.0 V
RL = 150 Ω
RL = 1 kΩ
Sinking and sourcing
Enabled
POWER DOWN pins = +VS
+VS = 4 V to 6 V, −VS = −5 V
+VS = 5 V, −VS = −4 V to −6 V,
POWER DOWN pins = −VS
Rev. A | Page 4 of 16
±2
±3.9
5
13.5
−63
−59
17.9
0.3
−66
−62
+13
+1
+13
12
20.5
0.5
mV
μA
μA
kΩ
V
mA
mA
dB
dB
ADA4861-3
ABSOLUTE MAXIMUM RATINGS
Table 3.
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 amplifiers’ drive at the output. The quiescent power
is the voltage between the supply pins (VS) times the quiescent
current (IS).
Rating
12.6 V
See Figure 3
−VS + 1 V to +VS − 1 V
±VS
−65°C to +125°C
−40°C to +105°C
JEDEC J-STD-20
150°C
PD = Quiescent Power + (Total Drive Power − Load Power)
⎛V V
⎞ V 2
PD = (VS × I S ) + ⎜ S × OUT ⎟ – OUT
RL ⎠
RL
⎝ 2
THERMAL RESISTANCE
θJA is specified for the worst-case conditions, that is, θJA is
specified for device soldered in circuit board for surface-mount
packages.
Table 4. Thermal Resistance
Package Type
14-lead SOIC_N
θJA
90
Unit
°C/W
Maximum Power Dissipation
The maximum safe power dissipation for the ADA4861-3 is
limited by the associated rise in junction temperature (TJ) on
the die. At approximately 150°C, which is the glass transition
temperature, the plastic changes its properties. Even temporarily
exceeding this temperature limit can change the stresses that the
package exerts on the die, permanently shifting the parametric
performance of the amplifiers. Exceeding a junction temperature of
150°C for an extended period can result in changes in silicon
devices, potentially causing degradation or loss of functionality.
RMS output voltages should be considered.
Airflow increases heat dissipation, effectively reducing θJA.
In addition, more metal directly in contact with the package
leads and through holes under the device reduces θJA.
Figure 3 shows the maximum safe power dissipation in the
package vs. the ambient temperature for the 14-lead SOIC_N
(90°C/W) on a JEDEC standard 4-layer board. θJA values are
approximations.
2.5
2.0
1.5
1.0
0.5
05708-002
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.
MAXIMUM POWER DISSIPATION (W)
Parameter
Supply Voltage
Power Dissipation
Common-Mode Input Voltage
Differential Input Voltage
Storage Temperature
Operating Temperature Range
Lead Temperature
Junction Temperature
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
ADA4861-3
TYPICAL PERFORMANCE CHARACTERISTICS
RL = 150 Ω and CL = 4 pF, unless otherwise noted.
VS = ±5V
VOUT = 0.2V p-p
1
G = +1,
RF = 499Ω
–2
–3
G = +2, RF = RG = 301Ω
G = –1, RF = RG = 301Ω
G = +5, RF = 200Ω, RG = 49.9Ω
–4
–1
G = +2, RF = RG = 301Ω
–2
G = –1, RF = RG = 301Ω
–3
G = +5, RF = 200Ω, RG = 49.9Ω
–4
G = +10, RF = 200Ω, RG = 22.1Ω
G = +10, RF = 200Ω, RG = 22.1Ω
–5
05708-038
–5
–6
0.1
1
10
100
–6
0.1
1000
1
FREQUENCY (MHz)
G = –1, RF = RG = 301Ω
0
1000
VS = 5V
VOUT = 2V p-p
G = +5, RF = 200Ω, RG = 49.9Ω
–1
G = +5, RF = 200Ω, RG = 49.9Ω
–2
G = +1, RF = 499Ω
NORMALIZED GAIN (dB)
0
G = +2, RF = RG = 301Ω
–3
–4
–5
G = +10, RF = 200Ω, RG = 22.1Ω
–6
0.1
1
10
100
G = +1, RF = 499Ω
–1
–2
G = +2, RF = RG = 301Ω
–3
G = +10, RF = 200Ω, RG = 22.1Ω
–4
–5
05708-028
NORMALIZED GAIN (dB)
100
Figure 7. Small Signal Frequency Response for Various Gains
1
VS = ±5V
VOUT = 2V p-p
10
FREQUENCY (MHz)
Figure 4. Small Signal Frequency Response for Various Gains
1
G = +1, RF = 499Ω
05708-037
–1
VS = 5V
VOUT = 0.2V p-p
0
NORMALIZED GAIN (dB)
NORMALIZED GAIN (dB)
0
G = –1, RF = RG = 301Ω
–6
0.1
1000
1
FREQUENCY (MHz)
1000
Figure 8. Large Signal Frequency Response for Various Gains
7
G = +2
VOUT = 2V p-p
RF = RG = 301Ω
6.0
100
FREQUENCY (MHz)
Figure 5. Large Signal Frequency Response for Various Gains
6.1
10
05708-027
1
VS = ±5V
G = +2
VOUT = 1V p-p
6
CLOSED-LOOP GAIN (dB)
5.8
VS = ±5V
5.7
VS = +5V
5.6
5.5
5.4
5
VOUT = 2V p-p
4
3
VOUT = 4V p-p
2
5.3
1
10
100
0
0.1
1000
05708-029
5.2
5.1
0.1
1
05708-011
CLOSED-LOOP GAIN (dB)
5.9
1
10
100
1000
FREQUENCY (MHz)
FREQUENCY (MHz)
Figure 6. Large Signal 0.1 dB Flatness
Figure 9. Large Signal Frequency Response for Various Output Levels
Rev. A | Page 6 of 16
ADA4861-3
7
7
RF = 301Ω
6
RF = 301Ω
6
RF = 499Ω
4
RF = 604Ω
3
2
VS = ±5V
G = +2
RG = RF
VOUT = 0.2V p-p
1
0
0.1
1
10
100
5
RF = 499Ω
4
RF = 604Ω
3
2
1
0
0.1
1000
VS = ±5V
G = +2
RF = RG
VOUT = 2V p-p
1
FREQUENCY (MHz)
–40
–50
–80
VOUT = 2V p-p
HD3
VOUT = 3V p-p
HD3
1
VOUT = 2V p-p
HD2
–70
VOUT = 3V p-p
HD3
–80
VOUT = 2V p-p
HD3
–90
–100
50
10
VOUT = 3V p-p
HD2
–60
1
Figure 11. Harmonic Distortion vs. Frequency
Figure 14. Harmonic Distortion vs. Frequency
–40
VS = 5V
G = +2
VOUT = 2V p-p
HD3
–50
–50
VOUT = 2V p-p
HD2
DISTORTION (dBc)
–60
–70
–80
–90
VOUT = 1V p-p
HD2
VOUT = 1V p-p
HD3
1
10
VOUT = 2V p-p
HD2
–70
VOUT = 1V p-p
HD2
–80
–90
VOUT = 1V p-p
HD3
–100
05708-048
–100
VOUT = 2V p-p
HD3
–110
50
FREQUENCY (MHz)
05708-050
VS = 5V
G = +1
–60
50
10
FREQUENCY (MHz)
FREQUENCY (MHz)
–40
05708-051
DISTORTION (dBc)
VOUT = 2V p-p
HD2
–70
05708-049
DISTORTION (dBc)
VOUT = 3V p-p
HD2
–90
DISTORTION (dBc)
1000
VS = ±5V
G = +2
VS = ±5V
G = +1
–60
–110
100
Figure 13. Large Signal Frequency Response vs. RF
–50
–100
10
FREQUENCY (MHz)
Figure 10. Small Signal Frequency Response vs. RF
–40
05708-013
CLOSED-LOOP GAIN (dB)
RF = 402Ω
5
05708-012
CLOSED-LOOP GAIN (dB)
RF = 402Ω
1
10
FREQUENCY (MHz)
Figure 15. Harmonic Distortion vs. Frequency
Figure 12. Harmonic Distortion vs. Frequency
Rev. A | Page 7 of 16
50
ADA4861-3
200
200
2.7
2.7
2.5
–100
2.4
G = +1
VOUT = 0.2V p-p
TIME = 5ns/DIV
2.3
0
2.5
–100
2.4
G = +2
VOUT = 0.2V p-p
TIME = 5ns/DIV
–200
Figure 16. Small Signal Transient Response for Various Supplies
Figure 19. Small Signal Transient Response for Various Supplies
200
200
CL = 9pF
CL = 9pF
OUTPUT VOLTAGE (mV)
100
CL = 4pF
0
–100
VS = ±5V
G = +1
VOUT = 0.2V p-p
TIME = 5ns/DIV
–200
05708-040
OUTPUT VOLTAGE (mV)
CL = 6pF
Figure 17. Small Signal Transient Response for Various Capacitor Loads
2.7
CL = 6pF
0
–100
Figure 20. Small Signal Transient Response for Various Capacitor Loads
2.7
CL = 9pF
OUTPUT VOLTAGE (V)
CL = 4pF
2.5
Figure 18. Small Signal Transient Response for Various Capacitor Loads
CL = 4pF
2.6
CL = 6pF
2.5
2.4
VS = 5V
G = +1
VOUT = 0.2V p-p
TIME = 5ns/DIV
05708-039
2.3
VS = ±5V
G = +2
VOUT = 0.2V p-p
TIME = 5ns/DIV
–200
CL = 9pF
2.6
2.4
CL = 4pF
100
CL = 6pF
OUTPUT VOLTAGE (V)
2.3
2.3
VS = 5V
G = +2
VOUT = 0.2V p-p
TIME = 5ns/DIV
05708-041
–200
VS = ±5V
OUTPUT VOLTAGE (V)
+VS = 5V, –VS = 0V
0
2.6
05708-014
VS = ±5V
100
05708-042
2.6
OUTPUT VOLTAGE (mV)
±VS = 5V
100
OUTPUT VOLTAGE (V)
+VS = 5V, –VS = 0V
VS = +5V
05708-015
OUTPUT VOLTAGE (mV)
±VS = 5V
VS = +5V
Figure 21. Small Signal Transient Response for Various Capacitor Loads
Rev. A | Page 8 of 16
ADA4861-3
1.0
3.0
0
2.5
–0.5
2.0
G = +1
VOUT = 2V p-p
TIME = 5ns/DIV
1.0
VS = ±5V
G = +1
VOUT = 2V p-p
TIME = 5ns/DIV
CL = 9pF
CL = 6pF
OUTPUT VOLTAGE (V)
CL = 4pF
0
–0.5
Figure 26. Large Signal Transient Response for Various Capacitor Loads
4.0
CL = 9pF
VS = ±5V
G = +2
VOUT = 2V p-p
TIME = 5ns/DIV
–1.5
CL = 6pF
CL = 9pF
CL = 6pF
3.5
3.5
OUTPUT VOLTAGE (V)
CL = 4pF
3.0
2.5
2.0
VS = 5V
G = +1
VOUT = 2V p-p
TIME = 5ns/DIV
CL = 4pF
3.0
2.5
2.0
1.5
05708-030
OUTPUT VOLTAGE (V)
1.0
0.5
–1.0
05708-031
OUTPUT VOLTAGE (V)
CL = 4pF
Figure 23. Large Signal Transient Response for Various Capacitor Loads
1.0
1.5
G = +2
VOUT = 2V p-p
TIME = 5ns/DIV
1.0
–1.5
1.5
2.0
1.5
CL = 9pF CL = 6pF
–0.5
4.0
–0.5
Figure 25. Large Signal Transient Response for Various Supplies
0
–1.0
2.5
–1.5
1.0
0.5
3.0
0
–1.0
Figure 22. Large Signal Transient Response for Various Supplies
1.5
VS = ±5V
0.5
05708-033
–1.5
1.5
3.5
Figure 24. Large Signal Transient Response for Various Capacitor Loads
1.0
VS = 5V
G = +2
VOUT = 2V p-p
TIME = 5ns/DIV
05708-032
–1.0
4.0
OUTPUT VOLTAGE (V)
+VS = 5V, –VS = 0V
3.5
VS = +5V
05708-016
VS = ±5V
0.5
1.5
OUTPUT VOLTAGE (V)
±VS = 5V
OUTPUT VOLTAGE (V)
±VS = 5V
1.0
4.0
OUTPUT VOLTAGE (V)
+VS = 5V, –VS = 0V
VS = +5V
05708-017
1.5
Figure 27. Large Signal Transient Response for Various Capacitor Loads
Rev. A | Page 9 of 16
ADA4861-3
1800
1600
VS = ±5V
G = +2
1200
POSITIVE SLEW RATE
1400
POSITIVE SLEW RATE
1000
SLEW RATE (V/µs)
SLEW RATE (V/µs)
1400
VS = ±5V
G = +1
1200
1000
800
NEGATIVE SLEW RATE
600
800
NEGATIVE SLEW RATE
600
400
400
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
05708-018
0
5.0
0
0.25
0.50
0.75
INPUT VOLTAGE (V p-p)
Figure 28. Slew Rate vs. Input Voltage
700
700
POSITIVE SLEW RATE
VS = 5V
G = +2
2.25
2.50
POSITIVE SLEW RATE
300
200
100
100
0
0.5
1.0
1.5
2.5
2.0
0
3.0
05708-019
SLEW RATE (V/µs)
NEGATIVE SLEW RATE
0
0.25
0.50
INPUT VOLTAGE (V p-p)
1.00
0.75
1.25
1.00
1.50
INPUT VOLTAGE (V p-p)
Figure 29. Slew Rate vs. Input Voltage
Figure 32. Slew Rate vs. Input Voltage
1.00
VIN
0.75
t = 0s
0.75
VS = ±5V
G = +2
VOUT = 2V p-p
TIME = 5ns/DIV
0.50
SETTLING TIME (%)
1V
0.25
0
–0.25
–0.50
1V
0.25
0
–0.25
–0.50
–0.75
t = 0s
VS = ±5V
G = +2
VOUT = 2V p-p
TIME = 5ns/DIV
–0.75
05708-022
SETTLING TIME (%)
2.00
400
200
05708-021
SLEW RATE (V/µs)
NEGATIVE SLEW RATE
300
–1.00
1.75
500
400
0.50
1.50
600
500
0
1.25
Figure 31. Slew Rate vs. Input Voltage
VS = 5V
G = +1
600
1.00
INPUT VOLTAGE (V p-p)
–1.00
Figure 30. Settling Time Rising Edge
VIN
Figure 33. Settling Time Falling Edge
Rev. A | Page 10 of 16
05708-020
0
200
05708-036
200
ADA4861-3
1000
VS = ±5V
G = +2
0
0
VS = ±5V, +5V
G = +2
VOUT = 2V p-p
–10
–90
CROSSTALK (dB)
PHASE
10
PHASE (Degrees)
TRANSIMPEDANCE
–30
–40
–50
–60
–70
–135
1
0.1
1
10
05708-024
–180
1000
100
05708-044
–80
0.1
0.01
–90
–100
0.1
1
10
–20
–30
–40
–PSR
–50
+PSR
–60
05708-023
–70
–80
0.01
0.1
1
10
100
VS = ±5V
G = +2
VIN = 2V p-p
–10
–20
–30
–40
–50
–60
05708-045
COMMON-MODE REJECTION (dB)
POWER SUPPLY REJECTION (dB)
0
VS = ±5V
G = +2
–10
–70
0.01
1000
0.1
1
5.5
VS = ±5V
G = +2
f = 1MHz
1
0
–1
–2
–3
05708-035
–4
–5
0
100
200
300
400
500
600
700
800
900
4.5
OUTPUT VOLTAGE
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
05708-034
OUTPUT VOLTAGE
2
–6
1000
VS = 5V
G = +2
f = 1MHz
INPUT VOLTAGE × 2
5.0
OUTPUT AND INPUT VOLTAGE (V)
INPUT VOLTAGE × 2
5
3
100
Figure 38. Common-Mode Rejection vs. Frequency
Figure 35. Power Supply Rejection vs. Frequency
4
10
FREQUENCY (MHz)
FREQUENCY (MHz)
6
1000
Figure 37. Large Signal All-Hostile Crosstalk
Figure 34. Transimpedance and Phase vs. Frequency
0
100
FREQUENCY (MHz)
FREQUENCY (MHz)
OUTPUT AND INPUT VOLTAGE (V)
TRANSIMPEDANCE (kΩ)
–20
–45
100
0
–0.5
1000
TIME (ns)
0
100
200
300
400
500
600
700
800
TIME (ns)
Figure 36. Output Overdrive Recovery
Figure 39. Output Overdrive Recovery
Rev. A | Page 11 of 16
900
1000
ADA4861-3
60
30
25
20
15
10
05708-052
5
0
10
100
1k
10k
VS = ±5V, +5V
50
40
30
INVERTING INPUT
20
NONINVERTING
INPUT
10
05708-053
VS = ±5V, +5V
INPUT CURRENT NOISE (pA/ Hz)
INPUT VOLTAGE NOISE (nV/ Hz)
35
0
10
100k
100
1k
FREQUENCY (Hz)
10k
100k
FREQUENCY (Hz)
Figure 40. Input Voltage Noise vs. Frequency
Figure 43. Input Current Noise vs. Frequency
19
20
TOTAL SUPPLY CURRENT (mA)
17
16
15
4
5
6
7
8
9
10
11
17
VS = +5V
16
15
14
12
–40
12
05708-025
14
VS = ±5V
18
13
05708-043
TOTAL SUPPLY CURRENT (mA)
19
18
–25
–10
5
SUPPLY VOLTAGE (V)
20
35
50
65
80
95
110
125
TEMPERATURE (°C)
Figure 41. Total Supply Current vs. Supply Voltage
Figure 44. Total Supply Current at Various Supplies vs. Temperature
25
20
20
15
5
VS = +5V
0
–5
–10
–15
–20
–25
–5
–4
–3
–2
–1
0
1
2
3
4
5
VCM (V)
10
VS = ±5V
5
VS = +5V
0
–5
–10
–15
–5
05708-026
VS = ±5V
05708-046
INPUT VOS (mV)
10
INPUT BIAS CURRENT (μA)
15
–4
–3
–2
–1
0
1
2
3
OUTPUT VOLTAGE (V)
Figure 42. Input VOS vs. Common-Mode Voltage
Figure 45. Input Bias Current vs. Output Voltage
Rev. A | Page 12 of 16
4
5
ADA4861-3
APPLICATIONS
GAIN CONFIGURATIONS
20 MHz ACTIVE LOW-PASS FILTER
Unlike conventional voltage feedback amplifiers, the feedback
resistor has a direct impact on the closed-loop bandwidth and
stability of the current feedback op amp circuit. Reducing the
resistance below the recommended value can make the amplifier
response peak and even become unstable. Increasing the size
of the feedback resistor reduces the closed-loop bandwidth.
Table 5 provides a convenient reference for quickly determining
the feedback and gain set resistor values and bandwidth for
common gain configurations.
The ADA4861-3 triple amplifier lends itself to higher order
active filters. Figure 48 shows a 28 MHz, 6-pole, Sallen-Key
low-pass filter.
R11
210kΩ
–
R1
562Ω
VIN
C1
10pF
RG (Ω)
N/A
301
301
49.9
22.1
−3 dB SS BW (MHz)
730
350
370
180
80
Large Signal
0.1 dB Flatness
90
60
100
30
15
C2
10pF
R9
210Ω
–
R3
562Ω
U2
OP AMP
+
R4
562Ω
C3
10pF
Conditions: VS = ±5 V, TA = 25°C, RL = 150 Ω.
Figure 46 and Figure 47 show the typical noninverting and
inverting configurations and recommended bypass capacitor
values.
+VS
R10
301Ω
OUT
C4
10pF
R7
210Ω
R8
301Ω
10µF
–
0.1µF
VIN
R5
562Ω
+
ADA4861-3
–
C5
10pF
VOUT
0.1µF
VOUT
C6
10pF
The filter has a gain of approximately 23 dB and flat frequency
response out to 22 MHz. This type of filter is commonly used at
the output of a video DAC as a reconstruction filter. The frequency
response of the filter is shown in Figure 49.
–VS
05708-005
RG
OUT
Figure 48. 28 MHz, 6-Pole Low-Pass Filter
10µF
RF
U3
OP AMP
+
R6
562Ω
05708-007
1
RF (Ω)
499
301
301
200
200
OUT
U1
OP AMP
+
R2
562Ω
Table 5. Recommended Values and Frequency Performance1
Gain
+1
−1
+2
+5
+10
R12
301Ω
Figure 46. Noninverting Gain
30
20
RF
+VS
10
10µF
–
ADA4861-3
VOUT
–10
–20
–30
–40
+
0.1µF
–50
–60
10µF
–VS
05708-047
RG
05708-006
VIN
MAGNITUDE (dB)
0
0.1µF
–70
1
10
100
FREQUENCY (MHz)
Figure 47. Inverting Gain
Figure 49. 20 MHz Low-Pass Filter Frequency Response
Rev. A | Page 13 of 16
200
ADA4861-3
RF
301Ω
RGB VIDEO DRIVER
RG
301Ω
PD3
4
1
5
75Ω
VIN (G)
75Ω
7
6
RG
301Ω
VIN (B)
RG
301Ω
VOUT2
75Ω
0.1µF
VIN
75Ω
10µF
–VS
Figure 51. Video Driver Schematic for Two Video Loads
0.1
VS = ±5V
RL = 75Ω
VOUT = 2V p-p
0
VOUT (R)
–0.2
–0.3
–0.4
–0.5
–0.6
–0.7
–0.9
75Ω
8
1
10
100
400
FREQUENCY (MHz)
VOUT (G)
Figure 52. Large Signal Frequency Response for Various Supplies, RL = 75 Ω
POWER-DOWN PINS
RF
301Ω
12
75Ω
75Ω
CABLE
–0.8
9
RG
301Ω
75Ω
+
RF
301Ω
10
75Ω
VOUT1
75Ω
05708-010
VIN (R)
2
–
75Ω
CABLE
NORMALIZED GAIN (dB)
0.1µF
3
75Ω
CABLE
–0.1
10µF
PD1
PD2
75Ω
0.1µF
ADA4861-3
For applications that require a fixed gain of +2, consider using
the ADA4862-3 with integrated RF and RG. The ADA4862-3 is
another high performance triple current feedback amplifier that
can simplify design and reduce board area.
+VS
10µF
+VS
05708-004
Figure 50 shows a typical RGB driver application using bipolar
supplies. The gain of the amplifier is set at +2, where RF = RG =
301 Ω. The amplifier inputs are terminated with shunt 75 Ω
resistors, and the outputs have series 75 Ω resistors for proper
video matching. In Figure 50, the POWER-DOWN pins are not
shown connected to any signal source for simplicity. If the
power-down function is not used, it is recommended that the
power-down pins be tied to the negative supply and not be left
floating (not connected).
75Ω
14
13
VOUT (B)
RF
301Ω
11
10µF
–VS
05708-003
0.1µF
Figure 50. RGB Video Driver
DRIVING TWO VIDEO LOADS
In applications that require two video loads be driven
simultaneously, the ADA4861-3 can deliver. Figure 51 shows
the ADA4861-3 configured with dual video loads. Figure 52
shows the dual video load 0.1 dB bandwidth performance.
The ADA4861-3 is equipped with three independent POWER
DOWN pins, one for each amplifier. This allows the user the
ability to reduce the quiescent supply current when an amplifier
is inactive. The power-down threshold levels are derived from
the voltage applied to the −VS pin. When used in single-supply
applications, this is especially useful with conventional logic
levels. The amplifier is powered down when the voltage applied
to the POWER DOWN pins is greater than −VS + 1 V. In a
single-supply application, this is > +1 V (that is, 0 V + 1 V), in a
±5 V supply application, the voltage is > −4 V. The amplifier is
enabled whenever the POWER DOWN pins are left either open
or the voltage on the POWER DOWN pins is lower than 1 V
above −VS. If the POWER DOWN pins are not used, it is best to
connect them to the negative supply.
Rev. A | Page 14 of 16
ADA4861-3
SINGLE-SUPPLY OPERATION
POWER SUPPLY BYPASSING
The ADA4861-3 can also be operated from a single power
supply. Figure 53 shows the schematic for a single 5 V supply
video driver. The input signal is ac-coupled into the amplifier
via C1. Resistor R2 and Resistor R4 establish the input midsupply
reference for the amplifier. Capacitor C5 prevents constant
current from being drawn through the gain set resistor and
enables the ADA4861-3 at dc to provide unity gain to the input
midsupply voltage, thereby establishing the output voltage dc
operating point. Capacitor C6 is the output coupling capacitor.
For more information on single-supply operation of op amps,
see www.analog.com/library/analogDialogue/archives/3502/avoiding/.
Careful attention must be paid to bypassing the power supply
pins of the ADA4861-3. 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, 2.2 μF
to 47 μF capacitor located in proximity to the ADA4861-3 is
required to provide good decoupling for lower frequency
signals. The actual value is determined by the circuit transient
and frequency requirements. In addition, 0.1 μF 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.
+5V
R2
50kΩ
C3
2.2µF
R4
50kΩ
C4
0.01µF
R3
1kΩ
C6
220µF
VIN
R1
50Ω
LAYOUT
C1
22µF
R5
75Ω
VOUT
R6
75Ω
ADA4861-3
C5
22µF
–VS
Figure 53. Single-Supply Video Driver Schematic
05708-054
+5V
C2
1µF
As is the case with all high-speed applications, careful attention
to printed circuit board (PCB) layout details prevents associated
board parasitics from becoming problematic. The ADA4861-3
can operate at up to 730 MHz; therefore, proper RF design
techniques must be employed. 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
and under the input and output pins reduces stray capacitance.
Signal lines connecting the feedback and gain resistors should
be kept as short as possible to minimize the inductance and
stray capacitance associated with these traces. 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)
through the board. Adherence to microstrip or stripline design
techniques for long signal traces (greater than 1 inch) is
recommended. For more information on high speed board
layout, go to: www.analog.com and
www.analog.com/library/analogDialogue/archives/3909/layout.html.
Rev. A | Page 15 of 16
ADA4861-3
OUTLINE DIMENSIONS
8.75 (0.3445)
8.55 (0.3366)
4.00 (0.1575)
3.80 (0.1496)
0.25 (0.0098)
0.10 (0.0039)
14
8
1
7
1.27 (0.0500)
BSC
COPLANARITY
0.10
0.51 (0.0201)
0.31 (0.0122)
6.20 (0.2441)
5.80 (0.2283)
1.75 (0.0689)
1.35 (0.0531)
SEATING
PLANE
0.50 (0.0197)
× 45°
0.25 (0.0098)
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 54. 14-Lead Standard Small Outline Package [SOIC_N]
Narrow Body
(R-14)
Dimensions shown in millimeters and (inches)
ORDERING GUIDE
Model
ADA4861-3YRZ 1
ADA4861-3YRZ-RL1
ADA4861-3YRZ-RL71
1
Temperature Range
–40°C to +105°C
–40°C to +105°C
–40°C to +105°C
Package Description
14-Lead SOIC_N
14-Lead SOIC_N
14-Lead SOIC_N
Z = Pb-free part.
©2006 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D05708-0-3/06(A)
Rev. A | Page 16 of 16
Package Option
R-14
R-14
R-14
Ordering Quantity
1
2,500
1,000