REV. C
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.
a
Wideband,
Fast Settling Op Amp
AD840
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700
Fax: 617/326-8703
CONNECTION DIAGRAMS
FEATURES
Wideband AC Performance
Gain Bandwidth Product: 400 MHz (Gain
10)
Fast Settling: 100 ns to 0.01% for a 10 V Step
Slew Rate: 400 V/ s
Stable at Gains of 10 or Greater
Full Power Bandwidth: 6.4 MHz for 20 V p-p into a
500 Load
Precision DC Performance
Input Offset Voltage: 0.3 mV max
Input Offset Drift: 3 V/ C typ
Input Voltage Noise: 4 nV/
Hz
Open-Loop Gain: 130 V/mV into a 1 k Load
Output Current: 50 mA min
Supply Current: 12 mA max
APPLICATIONS
Video and Pulse Amplifiers
DAC and ADC Buffers
Line Drivers
Available in 14-Pin Plastic DIP, Hermetic Cerdip
and 20-Pin LCC Packages and in Chip Form
MIL-STD-883B Processing Available
PRODUCT DESCRIPTION
The AD840 is a member of the Analog Devices' family of wide
bandwidth operational amplifiers. This high speed/high precision
family includes, among others, the AD841, which is unity-
gain stable, and the AD842, which is stable at a gain of two or
greater and has 100 mA minimum output current drive. These
devices are fabricated using Analog Devices' junction isolated
complementary bipolar (CB) process. This process permits a
combination of dc precision and wideband ac performance
previously unobtainable in a monolithic op amp. In addition
to its 400 MHz gain bandwidth product, the AD840 offers
extremely fast settling characteristics, typically settling to within
0.01% of final value in 100 ns for a 10 volt step.
The AD840 remains stable over its full operating temperature
range at closed-loop gains of 10 or greater. It also offers a low
quiescent current of 12 mA maximum, a minimum output
current drive capability of 50 mA, a low input voltage noise of
4 nV/
Hz
and a low input offset voltage of 0.3 mV maximum
(AD840K).
The 400 V/
s slew rate of the AD840, along with its 400 MHz
gain bandwidth, ensures excellent performance in video and
pulse amplifier applications. This amplifier is ideally suited for
use in high frequency signal conditioning circuits and wide
bandwidth active filters. The extremely rapid settling time of the
AD840 makes it the preferred choice for data acquisition appli-
cations which require 12-bit accuracy. The AD840 is also ap-
propriate for other applications such as high speed DAC and
ADC buffer amplifiers and other wide bandwidth circuitry.
APPLICATION HIGHLIGHTS
1. The high slew rate and fast settling time of the AD840 make
it ideal for DAC and ADC buffers, line drivers and all types
of video instrumentation circuitry.
2. The AD840 is truly a precision amplifier. It offers 12-bit
accuracy to 0.01% or better and wide bandwidth, perfor-
mance previously available only in hybrids.
3. The AD840's thermally balanced layout and the high speed
of the CB process allow the AD840 to settle to 0.01% in
100 ns without the long "tails" that occur with other fast op
amps.
4. Laser wafer trimming reduces the input offset voltage to
0.3 mV max on the K grade, thus eliminating the need for
external offset nulling in many applications. Offset null pins
are provided for additional versatility.
5. Full differential inputs provide outstanding performance
in all standard high frequency op amp applications where
circuit gain will be 10 or greater.
6. The AD840 is an enhanced replacement for the HA2540.
Plastic DIP (N) Package
and
Cerdip (Q) Package
LCC (E) Package
AD840SPECIFICATIONS
Model
AD840J
AD840K
AD840S
Conditions
Min
Typ
Max
Min
Typ
Max
Min
Typ
Max
Units
INPUT OFFSET VOLTAGE
1
0.2
1
0.1
0.3
0.2
1
mV
T
MIN
T
MAX
1.5
0.7
2
mV
Offset Drift
5
3
5
V/
C
INPUT BIAS CURRENT
3.5
8
3.5
5
3.5
8
A
T
MIN
T
MAX
10
6
12
A
INPUT OFFSET CURRENT
0.1
0.4
0.1
0.2
0.1
0.4
A
T
MIN
T
MAX
0.5
0.3
0.6
A
INPUT CHARACTERISTICS
Differential Mode
Input Resistance
30
30
30
k
Input Capacitance
2
2
2
pF
INPUT VOLTAGE RANGE
Common Mode
10
12
10
12
10
12
V
Common-Mode Rejection
V
CM
=
10 V
90
110
106
115
90
110
dB
T
MIN
T
MAX
85
90
85
dB
INPUT VOLTAGE NOISE
f = 1 kHz
4
4
4
nV/
Hz
Wideband Noise
10 Hz to 10 MHz
10
10
10
V rms
OPEN-LOOP GAIN
V
O
=
10 V
R
LOAD
= 1 k
100
130
100
130
100
130
V/mV
T
MIN
T
MAX
50
80
75
100
50
80
V/mV
R
LOAD
= 500
75
100
75
V/mV
T
MIN
T
MAX
50
75
50
V/mV
OUTPUT CHARACTERISTICS
Voltage
R
LOAD
500
T
MIN
T
MAX
10
10
10
V
Current
V
OUT
=
10 V
50
50
50
mA
Output Resistance
Open Loop
15
15
15
FREQUENCY RESPONSE
Gain Bandwidth Product
V
OUT
= 90 mV p-p
A
V
= 10
400
400
400
MHz
Full Power Bandwidth
2
V
O
= 20 V p-p
R
LOAD
= 500
5.5
6.4
5.5
6.4
5.5
6.4
MHz
Rise Time
A
V
= 10
10
10
10
ns
Overshoot
3
A
V
= 10
20
20
20
%
Slew Rate
3
A
V
= 10
350
400
350
400
350
400
V/
s
Settling Time
3
10 V Step
A
V
= 10
to 0.1%
80
80
80
ns
to 0.01%
100
100
100
ns
OVERDRIVE RECOVERY
Overdrive
190
190
190
ns
+Overdrive
350
350
350
ns
DIFFERENTIAL GAIN
f = 4.4 MHz
0.025
0.025
0.025
%
DIFFERENTIAL PHASE
f = 4.4 MHz
0.04
0.04
0.04
Degree
POWER SUPPLY
Rated Performance
15
15
15
V
Operating Range
5
18
5
18
5
18
V
Quiescent Current
12
14
12
14
12
14
mA
T
MIN
T
MAX
16
16
18
mA
Power Supply Rejection Ratio
V
S
=
5 V to
18 V
90
100
94
100
90
100
dB
T
MIN
T
MAX
80
86
80
dB
TEMPERATURE RANGE
Rated Performance
4
0
+75
0
+75
55
+125
C
TRANSISTOR COUNT
# of Transistors
72
72
72
REV. C
2
(@ +25 C and 15 V dc, unless otherwise noted)
NOTES
1
Input offset voltage specifications are guaranteed after 5 minutes at T
A
= +25
C.
2
Full power bandwidth = slew rate/2
V
PEAK
.
3
Refer to Figures 22 and 23.
4
"S" grade T
MIN
T
MAX
specifications are tested with automatic test equipment at T
A
= 55
C and T
A
= +125
C.
All min and max specifications are guaranteed. Specifications shown in boldface are tested on all production units.
Specifications subject to change without notice.
AD840
REV. C
3
ABSOLUTE MAXIMUM RATINGS
1
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18 V
Internal Power Dissipation
2
Plastic (N) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 W
Cerdip (Q) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 W
LCC (E) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 W
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
V
S
Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . . .
6 V
Storage Temperature Range
Q, E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
C to +150
C
N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
C to +125
C
Junction Temperature (T
J
) . . . . . . . . . . . . . . . . . . . . . +175
C
Lead Temperature Range (Soldering 60 sec) . . . . . . . . +300
C
NOTES
1
Stresses above those listed under "Absolute Maximum Ratings" may cause
permanent damage to the device. This is a stress rating only, and 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
Maximum internal power dissipation is specified so that T
J
does not exceed
+175
C at an ambient temperature of +25
C.
Thermal Characteristics:
JC
JA
Derate at
Cerdip Package
30
C/W
110
C/W
8.7 mW/
C
Plastic Package
30
C/W
100
C/T
10 mW/
C
LCC Package
35
C/W
150
C/W
6.7 mW/
C
Recommended Heat Sink:
Aavid Engineering #602B
ORDERING GUIDE
Models
Package Options
2
AD840JN
N-14
AD840KN
N-14
AD840JQ
Q-14
AD840KQ
Q-14
AD840SQ
Q-14
AD840SQ-883B
Q-14
5962-89640012A
Q-14
AD840SE-883B
E-20A
5962-8964001CA
E-20A
NOTES
1
J and S Grade Chips also available.
2
N = Plastic DIP; Q = Cerdip; E = LCC (Leadless
2
Ceramic Chip Carrier).
Plastic DIP (N) Package
and
Cerdip (Q) Package
LCC (E) Package
AD840 Connection Diagrams
METALIZATION PHOTOGRAPH
Contact factory for latest dimensions.
Dimensions shown in inches and (mm).
Figure 1. Input Common-Mode
Range vs. Supply Voltage
Figure 4. Quiescent Current vs.
Supply Voltage
Figure 7. Quiescent Current vs.
Temperature
AD840Typical Characteristics
REV. C
4
(at +25 C and V
S
= 15 V, unless otherwise noted)
Figure 2. Output Voltage Swing
vs. Supply Voltage
Figure 5. Input Bias Current vs.
Temperature
Figure 8. Short-Circuit Current
Limit vs. Temperature
Figure 3. Output Voltage Swing
vs. Load Resistance
Figure 6. Output Impedance vs.
Frequency
Figure 9. Gain Bandwidth Product
vs. Temperature
AD840
REV. C
5
Figure 10. Open-Loop Gain and
Phase Margin Phase vs. Frequency
Figure 13. Common-Mode
Rejection vs. Frequency
Figure 16. Harmonic Distortion vs.
Frequency
Figure 11. Open-Loop Gain vs.
Supply Voltage
Figure 14. Large Signal Frequency
Response
Figure 17. Input Voltage Noise
Spectral Density
Figure 12. Power Supply Rejection
vs. Frequency
Figure 15. Output Swing and
Error vs. Settling Time
Figure 18. Slew Rate vs.
Temperature
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