ANALOG DEVICES ADA4856-3 Service Manual
Single-Supply, High Speed, Fixed G = +2,
www.BDTIC.com/ADI
FEATURES
Voltage feedback architecture
Rail-to-rail output swing: 0.1 V to 4.9 V
High speed amplifier
−3 dB bandwidth: 225 MHz
0.1 dB flatness at 2 V p-p: 74 MHz
Slew rate: 800 V/μs
Settling time to 0.1% with 2 V step: 5 ns
High input common-mode voltage range
−V
− 0.2 V to +VS − 1 V
S
Supply range: 3 V to 5.5 V
Differential gain error: 0.01%
Differential phase error: 0.01°
Low power
7.8 mA/amplifier typical supply current
Power-down feature
Available in 16-lead LFCSP
APPLICATIONS
Professional video
Consumer video
Imaging
Instrumentation
Base stations
Active filters
Buffers
GENERAL DESCRIPTION
The ADA4856-3 (triple) is a fixed gain of +2, single-supply, railto-rail output video amplifier. It provides excellent video
performance with 225 MHz, −3 dB bandwidth, 800 V/μs slew rate,
and 74 MHz, 0.1 dB flatness into a 150 Ω load. It has a wide
input common-mode voltage range that extends 0.2 V below
ground and 1 V below the positive rail. In addition, the output
voltage swings within 200 mV of either supply, making this video
amplifier easy to use on single-supply voltages as low as 3.3 V.
The ADA4856-3 offers a typical low power of 7.8 mA per amplifier,
while being capable of delivering up to 52 mA of load current.
It also features a power-down function for power sensitive
applications that reduces the supply current to 1 mA.
The ADA4856-3 is available in a 16-lead LFCSP and is designed
to work over the extended industrial temperature range of
−40°C to +105°C.
Rail-to-Rail Output Video Amplifier
ADA4856-3
CONNECTION DIAGRAM
OUT1
OUT3
V
= 2V p-p
S
–V
S
–V
= 3.3V, V
S
12
+V
11 OUT2
10 –IN2
+V
9
.
S
= 1.4V p-p
OUT
S
S
07686-001
07686-058
–IN1
+IN1
16 15 14 13
1
NC
2+IN2
NC
PD
ADA4856-3
3
4
5678
–IN3
+IN3
NOTES
1. NC = NO CONNECT .
2. EXPOSED PAD CONNECTED TO –V
Figure 1.
7
6
5
4
3
2
CLOSED-LOOP GAIN (dB)
1
0
1 10 100 1000
VS= 5V, V
VS= 3.3V, V
RL= 150
Figure 2. Large Signal Frequency Response
= 1.4V p-p
OUT
= 2V p-p
OUT
= 5V, V
V
S
OUT
FREQUENCY (MHz)
Rev. 0
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 ©2008 Analog Devices, Inc. All rights reserved.
ADA4856-3
www.BDTIC.com/ADI
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
Connection Diagram ....................................................................... 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
5 V Operation ............................................................................... 3
3.3 V Operation ............................................................................ 4
Absolute Maximum Ratings ............................................................ 5
Thermal Resistance ...................................................................... 5
Maximum Power Dissipation ..................................................... 5
ESD Caution .................................................................................. 5
Pin Configuration and Function Descriptions ............................. 6
Typical Performance Characteristics ............................................. 7
Theory of Operation ...................................................................... 12
Applications Information .............................................................. 13
Using the ADA4856-3 in Gains Equal to +1, −1 ........................ 13
Using the ADA4856-3 in Gains Equal to +3, +4, and +5 ..... 14
20 MHz Active Low-Pass Filter ................................................ 15
Video Line Driver ....................................................................... 15
Single-Supply Operation ........................................................... 16
Power Down ................................................................................ 16
Layout Considerations ............................................................... 16
Power Supply Bypassing ............................................................ 16
Outline Dimensions ....................................................................... 17
Ordering Guide .......................................................................... 17
REVISION HISTORY
10/08—Revision 0: Initial Version
Rev. 0 | Page 2 of 20
ADA4856-3
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SPECIFICATIONS
5 V OPERATION
TA = 25°C, +VS = 5 V, −VS = 0 V, G = +2, RL = 150 Ω to midsupply, unless otherwise noted.
Table 1.
Parameter Test Conditions Min Typ Max Unit
DYNAMIC PERFORMANCE
−3 dB Bandwidth VO = 0.1 V p-p 370 MHz
V
V
Bandwidth for 0.1 dB Flatness VO = 1.4 V p-p 90 MHz
V
Slew Rate VO = 2 V step 800 V/μs
Settling Time to 0.1% (Rise/Fall) VO = 2 V step 4.8/5.2 ns
NOISE/DISTORTION PERFORMANCE
Harmonic Distortion (HD2/HD3) fC = 5 MHz, VO = 2 V p-p, RL = 1 kΩ −92/−110 dBc
f
Crosstalk, Output to Output f = 5 MHz, G = +2 −80 dBc
Input Voltage Noise f = 100 kHz 14 nV/√Hz
Input Current Noise f = 100 kHz 2 pA/√Hz
Differential Gain Error 0.01 %
Differential Phase Error 0.01 Degrees
DC PERFORMANCE
Input Offset Voltage 1.3 3.4 mV
Input Offset Voltage Drift 5.5 μV/°C
Input Bias Current −3.8 μA
Input Offset Current ±0.05 μA
Closed-Loop Gain 1.95 2 2.05 V/V
Open-Loop Gain 90 dB
INPUT CHARACTERISTICS
Input Resistance 3.2 MΩ
Input Capacitance 0.5 pF
Input Common-Mode Voltage Range −VS − 0.2 +VS − 1 V
Common-Mode Rejection Ratio VCM = −0.2 V to +4 V 94 dB
OUTPUT CHARACTERISTICS
Output Voltage Swing 0.1 to 4.9 V
Linear Output Current Per Amplifier HD2 ≤ −60 dBc, RL = 10 Ω 52 mA
POWER-DOWN
Turn-On Time 78 ns
Turn-Off Time 950 ns
Input Bias Current Enabled 0.2 μA
Powered down −125 μA
Turn-On Voltage 3.75 V
POWER SUPPLY
Operating Range 3 5.5 V
Quiescent Current per Amplifier 7.8 mA
Supply Current When Disabled 1.1 mA
Power Supply Rejection Ratio ∆VS = 4.5 V to 5.5 V 96 dB
= 1.4 V p-p 225 MHz
O
= 2 V p-p 200 MHz
O
= 2 V p-p 74 MHz
O
= 20 MHz, VO = 2 V p-p, RL = 1 kΩ −68/−71 dBc
C
Rev. 0 | Page 3 of 20
ADA4856-3
www.BDTIC.com/ADI
3.3 V OPERATION
TA = 25°C, +VS = 3.3 V, −VS = 0 V, G = +2, RL = 150 Ω to midsupply, unless otherwise noted.
Table 2.
Parameter Test Conditions Min Typ Max Unit
DYNAMIC PERFORMANCE
−3 dB Bandwidth VO = 0.1 V p-p 370 MHz
V
Bandwidth for 0.1 dB Flatness VO = 2 V p-p 77 MHz
Slew Rate VO = 2 V step 800 V/μs
Settling Time to 0.1% (Rise/Fall) VO = 2 V step 4.8/7 ns
NOISE/DISTORTION PERFORMANCE
Harmonic Distortion (HD2/HD3) fC = 5 MHz, VO = 2 V p-p, RL = 1 kΩ −95/−128 dBc
f
Crosstalk, Output to Output f = 5 MHz, G = +2 −78 dBc
Input Voltage Noise f = 100 kHz 14 nV/√Hz
Input Current Noise f = 100 kHz 2 pA/√Hz
Differential Gain Error 0.01 %
Differential Phase Error 0.01 Degrees
DC PERFORMANCE
Input Offset Voltage 1.2 3 mV
Input Offset Voltage Drift 5.5 μV/°C
Input Bias Current −3.8 μA
Input Offset Current ±0.05 μA
Closed-Loop Gain 1.95 2 2.05 V/V
Open-Loop Gain 90 dB
INPUT CHARACTERISTICS
Input Resistance 3.2 MΩ
Input Capacitance 0.5 pF
Input Common-Mode Voltage Range −VS − 0.2 +VS − 1 V
Common-Mode Rejection Ratio VCM = −0.2 V to +2.3 V 94 dB
OUTPUT CHARACTERISTICS
Output Voltage Swing, Load Resistance 0.1 to 3.22 V
Linear Output Current Per Amplifier HD2 ≤ −60 dBc, RL = 10 Ω 49 mA
POWER-DOWN
Turn-On Time 78 ns
Turn-Off Time 950 ns
Turn-On Voltage 2.05 V
POWER SUPPLY
Operating Range 3 5.5 V
Quiescent Current per Amplifier 7.5 mA
Quiescent Current When Powered Down 0.98 mA
Power Supply Rejection Ratio ∆VS = 2.97 V to 3.63 V 94 dB
= 2 V p-p 225 MHz
O
= 20 MHz, VO = 2 V p-p, RL = 1 kΩ −74/−101 dBc
C
Rev. 0 | Page 4 of 20
ADA4856-3
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ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter Rating
Supply Voltage 6 V
Internal Power Dissipation1 See Figure 3
Common-Mode Input Voltage (−VS − 0.2 V) to (+VS − 1 V)
Differential Input Voltage ±VS
Output Short-Circuit Duration Observe power curves
Storage Temperature Range −65°C to +125°C
Operating Temperature Range −40°C to +105°C
Lead Temperature (Soldering, 10 sec) 300°C
1
Specification is for device in free air.
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
θJA is specified for the worst-case conditions, that is, θJA is specified
for a device soldered in a circuit board for surface-mount packages.
Table 4.
Package Type θJA θ
16-Lead LFCSP 67 17.5 °C/W
Unit
JC
MAXIMUM POWER DISSIPATION
The maximum power that can be safely dissipated by the
ADA4856-3 is limited by the associated rise in junction
temperature. The maximum safe junction temperature for
plastic encapsulated devices is determined by the glass transition
temperature of the plastic, approximately 150°C. Temporarily
exceeding this limit may cause a shift in parametric performance
due to a change in the stresses exerted on the die by the package.
Exceeding a junction temperature of 175°C for an extended
period can result in device failure.
To ensure proper operation, it is necessary to observe the
maximum power derating curves.
3.0
2.5
2.0
1.5
1.0
0.5
MAXIMUM POWER DISSIPATION (W)
0
–40
–30
Figure 3. Maximum Power Dissipation vs. Ambient Temperature
0
–20
102030405060708090
–10
AMBIENT TEMPERATURE (°C)
07686-103
100
ESD CAUTION
Rev. 0 | Page 5 of 20
ADA4856-3
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PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
–IN1
+IN1
16 15 14 13
S
–V
OUT1
NC
1
2+IN2
3
NC
4
PD
NOTES
1. NC = NO CONNECT .
2. EXPOSED PAD CONNECTED TO –V
ADA4856-3
TOP VIEW
(Not to Scale)
5678
–IN3
+IN3
OUT3
12
11 OUT2
10 –IN2
9
S
–V
S
Figure 4. Pin Configuration
Table 5. Pin Function Descriptions
Pin No. Mnemonic Description
1 NC No Connect.
2 +IN2 Noninverting Input 2.
3 NC No Connect.
4
PD
Power Down.
5 +IN3 Noninverting Input 3.
6 −IN3 Inverting Input 3.
7 OUT3 Output 3.
8 −VS Negative Supply.
9 +VS Positive Supply.
10 −IN2 Inverting Input 2.
11 OUT2 Output 2.
12 +VS Positive Supply.
13 −VS Negative Supply.
14 OUT1 Output 1.
15 −IN1 Inverting Input 1.
16 +IN1 Noninverting Input 1.
17 (EPAD) Exposed Pad (EPAD) The exposed pad must be connected to −VS.
+V
S
+V
S
.
07686-003
Rev. 0 | Page 6 of 20
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