ANALOG DEVICES AD823A Service Manual
Wide Supply Dual, 17 MHz, Rail-to-Rail
Data Sheet
FEATURES
Single-supply operation
Output swings rail-to-rail
Input voltage range extends below ground
Single-supply capability from 3 V to 36 V
High load drive
Capacitive load drive of 470 pF (G = +1, 25% overshoot)
Linear output current of 40 mA, 0.5 V from supplies
Excellent ac performance on 2.6 mA/amplifier
−3 dB bandwidth of 17 MHz, G = +1
325 ns settling time to 0.01% (2 V step)
Slew rate of 30 V/μs
Low distortion: −108 dBc at 20 kHz (G = −1, R
Good dc performance
700 μV maximum input offset voltage
1 μV/°C offset voltage drift
25 pA maximum input bias current
Low noise: 14 nV/√Hz at 10 kHz
No phase inversion with inputs to the supply rails
APPLICATIONS
Photodiode preamps
Active filters
12-bit to 16-bit data acquisition systems
Medical instrumentation
Precision instrumentation
GENERAL DESCRIPTION
The AD823A is a dual precision, 17 MHz, JFET input op amp
manufactured in the extra fast complementary bipolar (XFCB)
process. The AD823A can operate from a single supply of 3 V
to 36 V or from dual supplies of ±1.5 V to ±18 V. It has true
single-supply capability with an input voltage range extending
below ground in single-supply mode. Output voltage swing extends
to within 20 mV of each rail for IOUT ≤ 100 μA, providing
outstanding output dynamic range. It also has a linear output
current of 40 mA, 0.5 V from the supply rails.
An offset voltage of 700 μV maximum, an offset voltage drift of
1 μV/°C, and typical input bias currents of 0.3 pA provide dc
precision with source impedances up to 1 GΩ. The AD823A
provides 17 MHz, −3 dB bandwidth, and a 30 V/μs slew rate with
a low supply current of only 2.6 mA per amplifier. It also provides
low input voltage noise of 14 nV/√Hz and −108 dB SFDR at
20 kHz. The AD823A has low input capacitances (0.6 pF differential and 1.3 pF common mode) and drives more than 500 pF
of direct capacitive load as a follower. This lets the amplifier
handle a wide range of load conditions.
= 2 kΩ)
L
FET Input Amplifier
AD823A
CONNECTION DIAGRAM
1
OUT1
–IN1
2
3
+IN1
–V
4
S
AD823A
Figure 1. 8-Lead SOIC
AD823A
OUT1 1
2
–IN1
+IN1 3
–V
4
S
TOP VIEW
(Not to Scale)
Figure 2. 8-Lead MSOP
VS = 3V
C
= 50pF
L
G = +1
3.0V
1.5V
0V
500mV/DIV
Figure 3. Output Swing, +V
This combination of ac and dc performance, plus the outstanding
load drive capability, results in an exceptionally versatile amplifier for applications such as ADC drivers, high speed active filters,
and other low voltage, high dynamic range systems.
The AD823A is available over the industrial temperature range
of −40°C to +85°C and is offered in an 8-lead SOIC package and
an 8-lead MSOP package.
8
+V
S
OUT2
7
–IN2
6
+IN2
5
09439-001
+V
8
S
7
OUT2
–IN26
+IN25
09439-102
200µs/DIV
= +3 V, G = +1
S
9439-049
Rev. B
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
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Fax: 781.461.3113 ©2012 Analog Devices, Inc. All rights reserved.
AD823A Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Connection Diagram ....................................................................... 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
5 V Operation ............................................................................... 3
3.3 V Operation ............................................................................ 4
±15 V Operation ........................................................................... 5
Absolute Maximum Ratings ............................................................ 6
Thermal Resistance ...................................................................... 6
ESD Caution .................................................................................. 6
REVISION HISTORY
6/12—Rev. A to Rev. B
Added Text to Absolute Maximum Ratings Section .................... 6
Changes to Equation 8 ................................................................... 18
5/12—Revision A: Initial Version
Pin Configuration and Function Descriptions ..............................7
Typical Performance Characteristics ..............................................8
Theory of Operation ...................................................................... 14
Output Impedance ..................................................................... 14
Applications Information .............................................................. 15
Input Characteristics .................................................................. 15
Output Characteristics............................................................... 15
Wideband Photodiode Preamp ................................................ 16
Active Filter ................................................................................. 18
Maximizing Performance Through Proper Layout ............... 19
Outline Dimensions ....................................................................... 20
Ordering Guide .......................................................................... 20
Rev. B | Page 2 of 20
Data Sheet AD823A
Slew Rate
G = −1, V
= 4 V step
25
30 V/µs
V
= 2 V p-p, f = 20 kHz, G = +1, RL = 1 kΩ
−99 dBc
Maximum Offset over Temperature
0.2
1.3
mV
Open-Loop Gain
V
= 0.2 V to 4 V, RL = 2 kΩ
40
175 V/mV
IL = ±2 mA
0.026 to 4.96
V
B
SPECIFICATIONS
5 V OPERATION
TA = 25°C, +VS = 5 V, RL = 2 kΩ to 2.5 V, unless otherwise noted.
Table 1.
Parameter Conditions Min Typ Max Unit
DYNAMIC PERFORMANCE
−3 dB Bandwidth G = +1, V
Full Power Response V
OUT
Settling Time
To 0.1% G = −1, V
To 0.01% G = −1, V
NOISE/DISTORTION PERFORMANCE
Input Voltage Noise f = 10 kHz 14 nV/√Hz
Input Current Noise f = 1 kHz 1 fA/√Hz
Harmonic Distortion (SFDR) V
OUT
OUT
Crosstalk
f = 1 kHz RL = 5 kΩ −123 dB
f = 1 MHz RL = 5 kΩ −77 dB
DC PERFORMANCE
Initial Offset 0.12 0.7 mV
≤ 0.2 V p-p 14.1 17 MHz
OUT
= 2 V p-p 4.8 MHz
OUT
= 2 V step 240 ns
OUT
= 2 V step 325 ns
OUT
= 2 V p-p, f = 20 kHz, G = −1, RF = RG = 4 kΩ −108 dBc
Offset Drift 1 µV/°C
Input Bias Current VCM = 0 V to 4 V 0.3 25 pA
At T
VCM = 0 V to 4 V 10 25 pA
MAX
Input Offset Current 0.3 20 pA
At T
3.5 pA
MAX
OUT
T
to T
MIN
25 V/mV
MAX
INPUT CHARACTERISTICS
Input Common-Mode Voltage Range −0.2 to +3 −0.2 to +3.8 V
Input Resistance 1013 Ω
Input Capacitance Differential Mode 0.6 pF
Common Mode 1.3 pF
Common-Mode Rejection Ratio VCM = 0 V to 3 V 60 73 dB
OUTPUT CHARACTERISTICS
Output Voltage Swing
IL = ±100 µA 0.009 to 4.98 V
IL = ±10 mA 0.097 to 4.88 V
Linear Output Current V
= 0.5 V to 4.5 V 40 mA
OUT
Short-Circuit Current Sourcing to 2.5 V 50 mA
Sinking to 2.5 V 101 mA
Capacitive Load Drive G = +1 500 pF
POWER SUPPLY
Operating Range 3 36 V
Quiescent Current T
Power Supply Rejection Ratio VS = 5 V to 15 V, T
MIN
to T
, total 5.1 5.7 mA
MAX
to T
MIN
70 94 dB
MAX
Rev. | Page 3 of 20
AD823A Data Sheet
To 0.1%
G = −1, V
= 2 V step
350 ns
Input Voltage Noise
f = 10 kHz
14 nV/√Hz
f = 1 kHz
RL = 5 kΩ
−123
dB
Initial Offset
0.14 1 mV
At T
3.5 pA
Common Mode
1.3 pF
Output Voltage Swing
B
3.3 V OPERATION
TA = 25°C, +VS = 3.3 V, RL = 2 kΩ to 1.65 V, unless otherwise noted.
Table 2.
Parameter Conditions Min Typ Max Unit
DYNAMIC PERFORMANCE
−3 dB Bandwidth G = +1, V
Full Power Response V
OUT
Slew Rate G = −1, V
Settling Time
To 0.01% G = −1, V
NOISE/DISTORTION PERFORMANCE
Input Current Noise f = 1 kHz 1 fA/√Hz
Harmonic Distortion (SFDR) V
V
OUT
OUT
Crosstalk
f = 1 MHz RL = 5 kΩ −77 dB
DC PERFORMANCE
≤ 0.2 V p-p, VCM = 0.65 V 13.8 17.3 MHz
OUT
= 2 V p-p 3.7 MHz
= 2 V step, VCM = 0.65 V 18 23 V/µs
OUT
OUT
= 2 V step 460 ns
OUT
= 2 V p-p, f = 20 kHz, G = −1, RF = RG = 4 kΩ −108 dBc
= 2 V p-p, f = 20 kHz, G = +1, RL = 100 Ω −70 dBc
Maximum Offset over Temperature 0.3 1.8 mV
Offset Drift 1 µV/°C
Input Bias Current VCM = 0 V to 2 V 0.3 25 pA
At T
VCM = 0 V to 2 V 10 25 pA
MAX
Input Offset Current 0.3 20 pA
MAX
Open-Loop Gain V
T
to T
MIN
14 V/mV
MAX
= 0.2 V to 2 V, RL = 2 kΩ 16 63 V/mV
OUT
INPUT CHARACTERISTICS
Input Common-Mode Voltage Range
−0.2 to
−0.2 to +1.8 V
+1
Input Resistance 1013 Ω
Input Capacitance Differential Mode 0.6 pF
Common-Mode Rejection Ratio VCM = 0 V to 1 V 54 71 dB
OUTPUT CHARACTERISTICS
IL = ±100 µA 0.006 to 3.28 V
IL = ±2 mA 0.04 to 3.26 V
IL = ±10 mA 0.093 to 3.18 V
Linear Output Current V
= 0.5 V to 2.5 V 40 mA
OUT
Short-Circuit Current Sourcing to 1.5 V 44 mA
Sinking to 1.5 V 86 mA
Capacitive Load Drive G = +1 500 pF
POWER SUPPLY
Operating Range 3 36 V
Quiescent Current T
Power Supply Rejection Ratio VS = 3.3 V to 15 V, T
MIN
to T
, total 5.0 5.7 mA
MAX
to T
MIN
70 80 dB
MAX
Rev. | Page 4 of 20
Data Sheet AD823A
To 0.1%
G = −1, V
= 10 V step
380 ns
Input Voltage Noise
f = 10 kHz
13 nV/√Hz
DC PERFORMANCE
At T
VCM = 0 V
55
95
pA
Common-Mode Rejection Ratio
VCM = −15 V to +13 V
70
90 dB
IL = ±100 µA
−14.9 to +14.96
V
Linear Output Current
V
= −14.5 V to +14.5 V
44 mA
B
±15 V OPERATION
TA = 25°C, VS = ±15 V, RL = 2 kΩ to 0 V, unless otherwise noted.
Table 3.
Parameter Conditions Min Typ Max Unit
DYNAMIC PERFORMANCE
−3 dB Bandwidth G = +1, V
Full Power Response V
OUT
Slew Rate G = −1, V
Settling Time
To 0.01% G = −1, V
NOISE/DISTORTION PERFORMANCE
Input Current Noise f = 1 kHz 1 fA/√Hz
Harmonic Distortion (SFDR)
V
OUT
4 kΩ
V
OUT
Crosstalk
f = 1 kHz RL = 5 kΩ −123 dB
f = 1 MHz RL = 5 kΩ −77 dB
≤ 0.2 V p-p 16.5 19 MHz
OUT
= 2 V p-p 5.6 MHz
= 10 V step 31 35 V/µs
OUT
OUT
= 10 V step 510 ns
OUT
= 10 V p-p, f = 20 kHz, G = −1, RF = RG =
−101 dBc
= 10 V p-p, f = 20 kHz, G = +1, RL = 600 Ω −89 dBc
Initial Offset 0.8 3.5 mV
Maximum Offset over Temperature 1.0 5 mV
Offset Drift 1 µV/°C
Input Bias Current VCM = 0 V 1.3 25 pA
VCM = −10 V 3.5 pA
MAX
Input Offset Current 1.3 20 pA
At T
9.5 pA
MAX
Open-Loop Gain V
T
to T
MIN
80 V/mV
MAX
= +10 V to −10 V, RL = 2 kΩ 100 450 V/mV
OUT
INPUT CHARACTERISTICS
Input Common-Mode Voltage Range −15.2 to +13 −15.2 to +13.8 V
Input Resistance 1013 Ω
Input Capacitance Differential Mode 0.6 pF
Common Mode 1.3 pF
OUTPUT CHARACTERISTICS
Output Voltage Swing
IL = ±2 mA −14.97 to +14.96 V
IL = ±10 mA −14.91 to +14.89 V
OUT
Short-Circuit Current Sourcing to 0 V 78 mA
Sinking to 0 V 124 mA
Capacitive Load Drive G = +1 500 pF
POWER SUPPLY
Operating Range 3 36 V
Quiescent Current T
Power Supply Rejection Ratio VS = 5 V to 15 V, T
MIN
to T
, total 6.3 8.4 mA
MAX
to T
MIN
70 94 dB
MAX
Rev. | Page 5 of 20
AD823A Data Sheet
ABSOLUTE MAXIMUM RATINGS
Table 4.
Parameter Rating
Supply Voltage 36 V
Power Dissipation See Figure 4
Input Voltage (Common Mode) ±VS ± 0.7 V
Differential Input Voltage ±VS
Output Short-Circuit Duration See Figure 4
Storage Temperature Range −65°C to +125°C
Operating Temperature Range −40°C to +85°C
Lead Temperature (Soldering, 10 sec) 300°C
ESD Ratings (Human Body Model) 4500 V
ESD Ratings (Charged Device Model) 1250 V
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.
Use the part with caution at the 30 V supply as excessive output
current may overheat and damage the part.
THERMAL RESISTANCE
θJA is specified for the worst-case conditions, that is, a device
soldered in a circuit board for surface-mount packages.
The specification is for the device in free air.
Table 5. Thermal Resistance
Package Type θJA Unit
8-Lead SOIC_N 120 °C/W
8-Lead MSOP 133 °C/W
2.0
1.5
8-LEAD SO IC
1.0
8-LEAD MSOP
0.5
MAXIMUM POWER DISSIPATION (W)
0
–45 –35 –25 –15 –5 5 15 25 35 45 55 65 75 85
Figure 4. Maximum Power Dissipation vs. Temperature
AMBIENT TEMPERATURE (°C)
TJ = 150°C
09439-004
ESD CAUTION
Rev. B | Page 6 of 20
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