a
FEATURES
Replaces Hybrid Amplifiers in Many Applications
AC PERFORMANCE:
Settles to 0.01% in 350 ns
100 V/ s Slew Rate
12.8 MHz Min Unity Gain Bandwidth
1.75 MHz Full Power Bandwidth at 20 V p-p
DC PERFORMANCE:
0.25 mV Max Input Offset Voltage
5 V/ C Max Offset Voltage Drift
0.5 nA Input Bias Current
250 V/mV Min Open-Loop Gain
4 V p-p Max Voltage Noise, 0.1 Hz to 10 Hz
94 dB Min CMRR
Available in Plastic Mini-DIP, Hermetic CERDIP, and
SOIC Packages. Also Available in Tape and Reel in
Accordance with EIA-481A Standard
GENERAL DESCRIPTION
Precision, 16 MHz
CBFET Op Amp
AD845
CONNECTION DIAGRAMS
Plastic Mini-DIP (N) Package
and CERDIP (Q) Package
16-Lead SOIC
(R-16) Package
The AD845 is a fast, precise, N channel JFET input, monolithic
operational amplifier. It is fabricated using Analog Devices’
complementary bipolar (CB) process. Advanced laser-wafer
trimming technology enables the very low input offset voltage
and offset voltage drift performance to be realized. This preci-
sion, when coupled with a slew rate of 100 V/ms, a stable unity
gain bandwidth of 16 MHz, and a settling time of 350 ns to
0.01%—while driving a parallel load of 100 pF and 500
W—
represents a combination of features unmatched by any FET
input IC amplifier. The AD845 can easily be used to upgrade
many existing designs that use BiFET or FET input hybrid
amplifiers and, in some cases, those which use bipolar input
op amps.
The AD845 is ideal for use in applications such as active filters,
high speed integrators, photodiode preamps, sample-and-hold
amplifiers, and log amplifiers, and for buffering A/D and D/A
converters. The 250
mV
max input offset voltage makes offset
nulling unnecessary in many applications. The common-mode
rejection ratio of 110 dB over a
±
10 V input voltage range
represents exceptional performance for a JFET input high
speed op amp. This, together with a minimum open-loop
gain of 250 V/mV ensures that 12-bit performance is achieved,
even in unity gain buffer circuits.
The AD845 conforms to the standard op amp pinout except
that offset nulling is to V+. The AD845J and AD845K grade
devices are available specified to operate over the commercial
0∞C to 70∞C temperature range. AD845A and AD845B
devices are specified for operation over the –40∞C to +85∞C
industrial temperature range. The AD845S is specified to oper-
ate over the full military temperature range of –55∞C to +125∞C.
Both the industrial and military versions are available in 8-lead
CERDIP packages. The commercial version is available in an
8-lead plastic mini-DIP and 16-lead SOIC; J and S grade chips
are also available.
PRODUCT HIGHLIGHTS
1. The high slew rate, fast settling time, and dc precision of the
AD845 make it ideal for high speed applications requiring
12-bit accuracy.
2. The performance of circuits using the LF400, HA2520,
HA2522, HA2525, HA2620, HA2622, HA2625, 3550,
OPA605, and LH0062 can be upgraded in most cases.
3. The AD845 is unity gain stable and internally compensated.
4. The AD845 is specified while driving 100 pF/500
W
loads.
REV. E
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. 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: 781/326-8703
© 2003 Analog Devices, Inc. All rights reserved.
AD845* PRODUCT PAGE QUICK LINKS
Last Content Update: 02/23/2017
COMPARABLE PARTS
View a parametric search of comparable parts.
REFERENCE MATERIALS
Tutorials
•
MT-032: Ideal Voltage Feedback (VFB) Op Amp
•
MT-033: Voltage Feedback Op Amp Gain and Bandwidth
•
MT-047: Op Amp Noise
•
MT-048: Op Amp Noise Relationships: 1/f Noise, RMS
Noise, and Equivalent Noise Bandwidth
•
MT-049: Op Amp Total Output Noise Calculations for
Single-Pole System
•
MT-050: Op Amp Total Output Noise Calculations for
Second-Order System
•
MT-052: Op Amp Noise Figure: Don't Be Misled
•
MT-053: Op Amp Distortion: HD, THD, THD + N, IMD,
SFDR, MTPR
•
MT-056: High Speed Voltage Feedback Op Amps
•
MT-058: Effects of Feedback Capacitance on VFB and CFB
Op Amps
•
MT-059: Compensating for the Effects of Input
Capacitance on VFB and CFB Op Amps Used in Current-to-
Voltage Converters
•
MT-060: Choosing Between Voltage Feedback and
Current Feedback Op Amps
DOCUMENTATION
Application Notes
•
AN-402: Replacing Output Clamping Op Amps with Input
Clamping Amps
•
AN-417: Fast Rail-to-Rail Operational Amplifiers Ease
Design Constraints in Low Voltage High Speed Systems
•
AN-581: Biasing and Decoupling Op Amps in Single
Supply Applications
Data Sheet
•
AD845: Military Data Sheet
•
AD845: Precision, 16 MHz CBFET Op Amp Data Sheet
TOOLS AND SIMULATIONS
•
Analog Filter Wizard
•
Analog Photodiode Wizard
•
Power Dissipation vs Die Temp
•
VRMS/dBm/dBu/dBV calculators
•
AD845 SPICE Macro-Model
REFERENCE DESIGNS
•
CN0042
DESIGN RESOURCES
•
AD845 Material Declaration
•
PCN-PDN Information
•
Quality And Reliability
•
Symbols and Footprints
DISCUSSIONS
View all AD845 EngineerZone Discussions.
SAMPLE AND BUY
Visit the product page to see pricing options.
TECHNICAL SUPPORT
Submit a technical question or find your regional support
number.
DOCUMENT FEEDBACK
Submit feedback for this data sheet.
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AD845–SPECIFICATIONS
(@ 25 C and
Parameter
INPUT OFFSET VOLTAGE
1
Initial Offset
T
MIN
to T
MAX
Offset Drift
INPUT BIAS CURRENT
Initial
2
15 V dc, unless otherwise noted.)
Max
1.5
2.5
20
2
45/75
300
3/6.5
Min
AD845K/B
Typ
Max
0.1
1.5
0.5
0.25
0.4
5.0
1
18/38
100
1.2/2.6
Min
AD845S
Typ
0.25
Max
1.0
2.0
10
2
500
300
20
Unit
mV
mV
mV/∞C
nA
nA
pA
nA
kW
pF
V
V
dB
mV
p-p
nV/÷Hz
nV/÷Hz
nV/÷Hz
nV/÷Hz
nV/÷Hz
pA/÷Hz
V/mV
V/mV
V/mV
V
mA
W
MHz
MHz
ns
%
V/ms
Conditions
Min
AD845J/A
Typ
0.7
V
CM
= 0 V
T
MIN
to T
MAX
V
CM
= 0 V
T
MIN
to T
MAX
0.75
0.75
INPUT OFFSET CURRENT
Initial
INPUT CHARACTERISTICS
Input Resistance
Input Capacitance
INPUT VOLTAGE RANGE
Differential
Common-Mode
Common-Mode Rejection
INPUT VOLTAGE NOISE
25
15
25
10
11
4.0
±
20
+10.5/–13
110
4
80
60
25
18
12
0.1
200
100
70
12.5
50
5
12.8
16
1.75
20
20
100
13.6
500
250
250
125
75
12.5
10
11
4.0
±
20
+10.5/–13
113
4
80
60
25
18
12
0.1
500
250
200
100
50
12.5
50
5
16
1.75
20
20
100
13.6
10
11
4.0
±
20
+10.5/–13
110
4
80
60
25
18
12
0.1
500
250
V
CM
=
±
10 V
0.1 Hz to 10 Hz
f = 10 Hz
f = 100 Hz
f = 1 kHz
f = 10 kHz
f = 100 kHz
f = 1 kHz
V
O
=
±
10 V
R
LOAD
≥
2 kW
R
LOAD
≥
500
W
T
MIN
–T
MAX
10
86
10
94
10
86
INPUT CURRENT NOISE
OPEN-LOOP GAIN
OUTPUT CHARACTERISTICS
Voltage
R
LOAD
≥
500
W
Current
Short Circuit
Output Resistance
Open Loop
FREQUENCY RESPONSE
Small Signal
Full Power Bandwidth
3
Rise Time
Overshoot
Slew Rate
Settling Time
Unity Gain
V
O
=
±
10 V
R
LOAD
= 500
W
50
5
16
1.75
20
20
100
80
10 V Step
C
LOAD
= 100 pF
R
LOAD
= 500
W
to 0.01%
to 0.1%
f = 4.4 MHz
f = 4.4 MHz
94
94
350
250
0.04
0.02
±
15
350
250
0.04
0.02
±
15
18
4.75
95
500
350
250
0.04
0.02
±
15
4.75
88
110
10
500
ns
ns
%
Degree
V
V
dB
mA
DIFFERENTIAL GAIN
DIFFERENTIAL PHASE
POWER SUPPLY
Rated Performance
Operating Range
Rejection Ratio
Quiescent Current
4.75
V
S
=
±
5 to
±
15 V
88
T
MIN
to T
MAX
18
113
10
12
18
12
110
10
12
NOTES
1
Input offset voltage specifications are guaranteed after five minutes of operation at T
A
= 25∞C.
2
Bias current specifications are guaranteed maximum at either input after five minutes of operation at T
A
= 25∞C.
3
FPBW = slew rate/2
p
V peak.
4
S grade T
MIN
–T
MAX
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 at final electrical test. Results from these tests are
used to calculate outgoing quality levels.
Specifications subject to change without notice.
–2–
REV. E
AD845
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±
18 V
Internal Power Dissipation
2
Plastic Mini-DIP . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.6 W
CERDIP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.4 W
16-Lead SOIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.5 W
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +V
S
Output Short-Circuit Duration . . . . . . . . . . . . . . . . Indefinite
Differential Input Voltage . . . . . . . . . . . . . . . . . . +V
S
and –V
S
Storage Temperature Range
Q . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .–65∞C to +150∞C
N, R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .–65∞C to +125∞C
Lead Temperature Range (Soldering 60 sec) . . . . . . . . . 300∞C
NOTES
1
Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent 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
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
2
Mini-DIP package:
q
JA
= 100∞C/W; CERDIP package:
q
JA
= 110∞C/W; SOIC
package:
q
JA
= 100∞C/W.
ABSOLUTE MAXIMUM RATINGS
1
METALIZATION PHOTOGRAPH
Dimensions shown in inches and (mm).
Contact factory for latest dimensions.
SUBSTRATE CONNECTED TO +V
S
ORDERING GUIDE
Temperature
Range
Package
Description
Package
Option
1
Model
AD845JN
AD845KN
AD845JR-16
AD845JR-16-REEL
AD845JR-16-REEL7
AD845AQ
AD845BQ
AD845SQ
AD845SQ/883B
5962-8964501PA
2
AD845JCHIPS
0∞C to 70∞C
0∞C to 70∞C
0∞C to 70∞C
0∞C to 70∞C
0∞C to 70∞C
–40∞C to +85∞C
–40∞C to +85∞C
–55∞C to +125∞C
–55∞C to +125∞C
–55∞C to +125∞C
0∞C to 70∞C
8-Lead PDIP
8-Lead PDIP
16-Lead SOIC
Tape and Reel
Tape and Reel
8-Lead CERDIP
8-Lead CERDIP
8-Lead CERDIP
8-Lead CERDIP
8-Lead CERDIP
Die
N-8
N-8
R-16
R-16
R-16
Q-8
Q-8
Q-8
Q-8
Q-8
NOTES
1
N = Plastic DIP; Q = CERDIP; R = Small Outline IC (SOIC).
2
See military data sheet.
REV. E
–3–
AD845–Typical Performance Characteristics
TPC 1. Input Voltage Swing
vs. Supply Voltage
TPC 2. Output Voltage Swing
vs. Supply Voltage
TPC 3. Output Voltage Swing
vs. Resistive Load
TPC 4. Quiescent Current vs.
Supply Voltage
TPC 5. Input Bias Current vs.
Temperature
TPC 6. Magnitude of Output
Impedance vs. Frequency
TPC 7. Input Bias Current vs.
Common-Mode Voltage
TPC 8. Short-Circuit Current
Limit vs. Temperature
TPC 9. Unity-Gain Bandwidth
vs. Temperature
–4–
REV. E
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