Analog Devices AD820AR Datasheet
REV. D
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.
a
AD820
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700www.analog.com
Fax: 781/326-8703 © Analog Devices, Inc., 2002
Single Supply, Rail to Rail
Low Power FET-Input Op Amp
FUNCTIONAL BLOCK DIAGRAM
FEATURES
True Single Supply Operation
Output Swings Rail-to-Rail
Input Voltage Range Extends Below Ground
Single Supply Capability from 5 V to 36 V
Dual Supply Capability from ⴞ2.5 V to ⴞ18 V
Excellent Load Drive
Capacitive Load Drive Up to 350 pF
Minimum Output Current of 15 mA
Excellent AC Performance for Low Power
800 A Max Quiescent Current
Unity Gain Bandwidth: 1.8 MHz
Slew Rate of 3.0 V/s
Excellent DC Performance
800 V Max Input Offset Voltage
1 V/ⴗC Typ Offset Voltage Drift
25 pA Max Input Bias Current
Low Noise
13 nV/√Hz @ 10 kHz
APPLICATIONS
Battery-Powered Precision Instrumentation
Photodiode Preamps
Active Filters
12- to 14-Bit Data Acquisition Systems
Medical Instrumentation
Low Power References and Regulators
PRODUCT DESCRIPTION
The AD820 is a precision, low power FET input op amp that
can operate from a single supply of 5.0 V to 36 V, or dual supplies of ±2.5 V to ±18 V. It has true single supply capability
with an input voltage range extending below the negative rail,
50
0
10
15
5
1
10
0
30
20
25
35
40
45
98765432
INPUT BIAS CURRENT – pA
NUMBER OF UNITS
Figure 1. Typical Distribution of Input Bias Current
allowing the AD820 to accommodate input signals below ground
in the single supply mode. Output voltage swing extends to within
10 mV of each rail providing the maximum output dynamic range.
Offset voltage of 800 µV max, offset voltage drift of 1 µV/°C,
typical input bias currents below 25 pA and low input voltage noise
provide dc precision with source impedances up to a Gigaohm.
1.8 MHz unity gain bandwidth, –93 dB THD at 10 kHz and
3 V/µs slew rate are provided for a low supply current of 800 µA.
The AD820 drives up to 350 pF of direct capacitive load and
provides a minimum output current of 15 mA. This allows the
amplifier to handle a wide range of load conditions. This combination of ac and dc performance, plus the outstanding load drive
capability, results in an exceptionally versatile amplifier for the
single supply user.
The AD820 is available in two performance grades. The A and
B grades are rated over the industrial temperature range of
–40°C to +85°C.
The AD820 is offered in two varieties of 8-lead package: plastic
DIP, and surface mount (SOIC).
Figure 2. Gain of 2 Amplifier; VS = 5, 0,
V
IN
= 2.5V Sine Centered at 1.25 Volts
1
2
3
4
8
7
6
5
TOP VIEW
(Not to Scale)
AD820
NULL
–IN
+IN
–V
S
NC
+V
S
V
OUT
NULL
1
2
3
4
8
7
6
5
TOP VIEW
(Not to Scale)
AD820
NC
–IN
+IN
–V
S
NC
+V
S
V
OUT
NC
NC = NO CONNECT
REV. D
–2–
AD820–SPECIFICATIONS
AD820A AD820B
Parameter Conditions Min Typ Max Min Typ Max Unit
DC PERFORMANCE
Initial Offset 0.1 0.8 0.1 0.4 mV
Max Offset over Temperature 0.5 1.2 0.5 0.9 mV
Offset Drift 2 2 µV/°C
Input Bias Current V
O
= 0 V to 4 V 2 25 2 10 pA
at T
MAX
0.5 5 0.5 2.5 nA
Input Offset Current 2 20 2 10 pA
at T
MAX
0.5 0.5 nA
Open-Loop Gain V
O
= 0.2 V to 4 V
T
MIN
to T
MAX
RL = 100 kΩ 400 1000 500 1000 V/mV
400 400 V/mV
T
MIN
to T
MAX
RL = 10 kΩ 80 150 80 150 V/mV
80 80 V/mV
T
MIN
to T
MAX
RL = 1 kΩ 15 30 15 30 V/mV
10 10 V/mV
NOISE/HARMONIC PERFORMANCE
Input Voltage Noise
0.1 Hz to 10 Hz 2 2 µV p-p
f = 10 Hz 25 25 nV/√Hz
f = 100 Hz 21 21 nV/√Hz
f = 1 kHz 16 16 nV/√Hz
f = 10 kHz 13 13 nV/√Hz
Input Current Noise
0.1 Hz to 10 Hz 18 18 fA p-p
f = 1 kHz 0.8 0.8 fA/√Hz
Harmonic Distortion R
L
= 10 kΩ to 2.5 V
f = 10 kHz VO = 0.25 V to 4.75 V –93 –93 dB
DYNAMIC PERFORMANCE
Unity Gain Frequency 1.8 1.8 MHz
Full Power Response V
O
p-p = 4.5 V 210 210 kHz
Slew Rate 3 3 V/µs
Settling Time
to 0.1% V
O
= 0.2 V to 4.5 V 1.4 1.4 µs
to 0.01% 1.8 1.8 µs
INPUT CHARACTERISTICS
Common-Mode Voltage Range
1
–0.2 +4 –0.2 +4 V
T
MIN
to T
MAX
–0.2 +4 –0.2 +4 V
CMRR V
CM
= 0 V to 2 V 66 80 72 80 dB
T
MIN
to T
MAX
66 66 dB
Input Impedance
Differential 10
13
储0.5 1013储0.5 Ω储pF
Common Mode 1013储2.8 1013储2.8 Ω储pF
OUTPUT CHARACTERISTICS
Output Saturation Voltage
2
VOL–V
EE
I
SINK
= 20 µA5757mV
T
MIN
to T
MAX
10 10 mV
VCC–V
OH
I
SOURCE
= 20 µA10141014mV
T
MIN
to T
MAX
20 20 mV
V
OL–VEE
I
SINK
= 2 mA 40 55 40 55 mV
T
MIN
to T
MAX
80 80 mV
V
CC–VOH
I
SOURCE
= 2 mA 80 110 80 110 mV
T
MIN
to T
MAX
160 160 mV
VOL–V
EE
I
SINK
= 15 mA 300 500 300 500 mV
T
MIN
to T
MAX
1000 1000 mV
V
CC–VOH
I
SOURCE
= 15 mA 800 1500 800 1500 mV
T
MIN
to T
MAX
1900 1900 mV
Operating Output Current 15 15 mA
T
MIN
to T
MAX
12 12 mA
Short-Circuit Current 25 25 mA
Capacitive Load Drive 350 350 pF
POWER SUPPLY
Quiescent Current T
MIN
to T
MAX
620 800 620 800 µA
Power Supply Rejection VS+ = 5 V to 15 V 70 80 66 80 dB
T
MIN
to T
MAX
70 66 dB
(VS = 0, 5 V @ TA = 25ⴗC, VCM = 0 V, V
OUT
= 0.2 V unless otherwise noted.)
REV. D
–3–
AD820
SPECIFICATIONS
AD820A AD820B
Parameter Conditions Min Typ Max Min Typ Max Unit
DC PERFORMANCE
Initial Offset 0.1 0.8 0.3 0.4 mV
Max Offset over Temperature 0.5 1.5 0.5 1 mV
Offset Drift 2 2 µV/°C
Input Bias Current V
O
= –5 V to 4 V 2 25 2 10 pA
at T
MAX
0.5 5 0.5 2.5 nA
Input Offset Current 2 20 2 10 pA
at T
MAX
0.5 0.5 nA
Open-Loop Gain V
O
= 4 V to –4 V
R
L
= 100 kΩ 400 1000 400 1000 V/mV
T
MIN
to T
MAX
400 400 V/mV
R
L
= 10 kΩ 80 150 80 150 V/mV
T
MIN
to T
MAX
80 80 V/mV
R
L
= 1 kΩ 20 30 20 30 V/mV
T
MIN
to T
MAX
10 10 V/mV
NOISE/HARMONIC PERFORMANCE
Input Voltage Noise
0.1 Hz to 10 Hz 2 2 µV p-p
f = 10 Hz 25 25 nV/√Hz
f = 100 Hz 21 21 nV/√Hz
f = 1 kHz 16 16 nV/√Hz
f = 10 kHz 13 13 nV/√Hz
Input Current Noise
0.1 Hz to 10 Hz 18 18 fA p-p
f = 1 kHz 0.8 0.8 fA/√Hz
Harmonic Distortion R
L
= 10 kΩ
f = 10 kHz VO = ±4.5 V –93 –93 dB
DYNAMIC PERFORMANCE
Unity Gain Frequency 1.9 1.8 MHz
Full Power Response V
O
p-p = 9 V 105 105 kHz
Slew Rate 3 3 V/µs
Settling Time
to 0.1% V
O
= 0 V to ±4.5 V 1.4 1.4 µs
to 0.01% 1.8 1.8 µs
INPUT CHARACTERISTICS
Common-Mode Voltage Range
1
–5.2 +4 –5.2 +4 V
T
MIN
to T
MAX
–5.2 +4 –5.2 +4 V
CMRR V
CM
= –5 V to +2 V 66 80 72 80 dB
T
MIN
to T
MAX
66 66 dB
Input Impedance
Differential 10
13
储0.5 1013储0.5 Ω储pF
Common Mode 1013储2.8 1013储2.8 Ω储pF
OUTPUT CHARACTERISTICS
Output Saturation Voltage
2
VOL–V
EE
I
SINK
= 20 µA5757mV
T
MIN
to T
MAX
10 10 mV
V
CC–VOH
I
SOURCE
= 20 µA10141014mV
T
MIN
to T
MAX
20 20 mV
V
OL–VEE
I
SINK
= 2 mA 40 55 40 55 mV
T
MIN
to T
MAX
80 80 mV
VCC–V
OH
I
SOURCE
= 2 mA 80 110 80 110 mV
T
MIN
to T
MAX
160 160 mV
V
OL–VEE
I
SINK
= 15 mA 300 500 300 500 mV
T
MIN
to T
MAX
1000 1000 mV
V
CC–VOH
I
SOURCE
= 15 mA 800 1500 800 1500 mV
T
MIN
to T
MAX
1900 1900 mV
Operating Output Current 15 15 mA
T
MIN
to T
MAX
12 12 mA
Short-Circuit Current 30 30 mA
Capacitive Load Drive 350 350 pF
POWER SUPPLY
Quiescent Current T
MIN
to T
MAX
650 800 620 800 µA
Power Supply Rejection V
S
+ = 5 V to 15 V 70 80 70 80 dB
T
MIN
to T
MAX
70 70 dB
(VS = 0, 5 V @ TA = 25ⴗC, VCM = 0 V, V
OUT
= 0.2 V unless otherwise noted.)
REV. D
–4–
AD820–SPECIFICATIONS
AD820A AD820B
Parameter Conditions Min Typ Max Min Typ Max Unit
DC PERFORMANCE
Initial Offset 0.4 2 0.3 1.0 mV
Max Offset over Temperature 0.5 3 0.5 2 mV
Offset Drift 2 2 µV/°C
Input Bias Current V
CM
= 0 V 2 25 2 10 pA
V
CM
= –10 V 40 40 pA
at T
MAX
VCM = 0 V 0.5 5 0.5 2.5 nA
Input Offset Current 2 20 2 10 pA
at T
MAX
0.5 0.5 nA
Open-Loop Gain V
O
= +10 V to –10 V
R
L
= 100 kΩ 500 2000 500 2000 V/mV
T
MIN
to T
MAX
500 500 V/mV
R
L
= 10 kΩ 100 500 100 500 V/mV
T
MIN
to T
MAX
100 100 V/mV
R
L
= 1 kΩ 30 45 30 45 V/mV
T
MIN
to T
MAX
20 20 V/mV
NOISE/HARMONIC PERFORMANCE
Input Voltage Noise
0.1 Hz to 10 Hz 2 2 µV p-p
f = 10 Hz 25 25 nV/√Hz
f = 100 Hz 21 21 nV/√Hz
f = 1 kHz 16 16 nV/√Hz
f = 10 kHz 13 13 nV/√Hz
Input Current Noise
0.1 Hz to 10 Hz 18 18 fA p-p
f = 1 kHz 0.8 0.8 fA/√Hz
Harmonic Distortion R
L
= 10 kΩ
f = 10 kHz VO = ±10 V –85 –85 dB
DYNAMIC PERFORMANCE
Unity Gain Frequency 1.9 1.9 MHz
Full Power Response V
O
p-p = 20 V 45 45 kHz
Slew Rate 3 3 V/µs
Settling Time
to 0.1% V
O
= 0 V to ±10 V 4.1 4.1 µs
to 0.01% 4.5 4.5 µs
INPUT CHARACTERISTICS
Common-Mode Voltage Range
1
–15.2 +14 –15.2 +14 V
T
MIN
to T
MAX
–15.2 +14 –15.2 +14 V
CMRR V
CM
= –15 V to 12 V 70 80 74 90 dB
T
MIN
to T
MAX
70 74 dB
Input Impedance
Differential 1013储0.5 1013储0.5 Ω储pF
Common Mode 1013储2.8 1013储2.8 Ω储pF
OUTPUT CHARACTERISTICS
Output Saturation Voltage
2
VOL–V
EE
I
SINK
= 20 µA5757mV
T
MIN
to T
MAX
10 10 mV
V
CC–VOH
I
SOURCE
= 20 µA10141014mV
T
MIN
to T
MAX
20 20 mV
V
OL–VEE
I
SINK
= 2 mA 40 55 40 55 mV
T
MIN
to T
MAX
80 80 mV
V
CC–VOH
I
SOURCE
= 2 mA 80 110 80 110 mV
T
MIN
to T
MAX
160 160 mV
V
OL–VEE
I
SINK
= 15 mA 300 500 300 500 mV
T
MIN
to T
MAX
1000 1000 mV
V
CC–VOH
I
SOURCE
= 15 mA 800 1500 800 1500 mV
T
MIN
to T
MAX
1900 1900 mV
Operating Output Current 20 20 mA
T
MIN
to T
MAX
15 15 mA
Short-Circuit Current 45 45 mA
Capacitive Load Drive 350 350
POWER SUPPLY
Quiescent Current T
MIN
to T
MAX
700 900 700 900 µA
Power Supply Rejection V
S
+ = 5 V to 15 V 70 80 70 80 dB
T
MIN
to T
MAX
70 70 dB
(VS = ⴞ15 V @ TA = 25ⴗC, VCM = 0 V, V
OUT
= 0 V unless otherwise noted.)
REV. D
–5–
AD820
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
the AD820 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.
NOTES
1
This is a functional specification. Amplifier bandwidth decreases when the input common-mode voltage is driven in the range (+ VS – 1 V) to +VS.
Common-mode error voltage is typically less than 5 mV with the common-mode voltage set at 1 volt below the positive supply.
2
VOL–VEE is defined as the difference between the lowest possible output voltage (VOL) and the minus voltage supply rail (VEE).
VCC–VOH is defined as the difference between the highest possible output voltage (VOH) and the positive supply voltage (VCC).
Specifications subject to change without notice.
ABSOLUTE MAXIMUM RATINGS
1
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±18 V
Internal Power Dissipation
2
Plastic DIP (N) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6 W
SOIC (R) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 W
Input Voltage . . . . . . . . . . . . . . (+V
S
+ 0.2 V) to – (20 V + VS)
Output Short Circuit Duration . . . . . . . . . . . . . . . . Indefinite
Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . . ±30 V
Storage Temperature Range (N) . . . . . . . . . –65°C to +125°C
Storage Temperature Range (R) . . . . . . . . . –65°C to +150°C
Operating Temperature Range
AD820A/B . . . . . . . . . . . . . . . . . . . . . . . . . –40°C to +85°C
Lead Temperature Range
(Soldering 60 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . 260°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; 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
8-Lead Plastic DIP Package: θJA = 90°C/W
8-Lead SOIC Package: θJA = 160°C/W
ORDERING GUIDE
Temperature Package Package
Model Range Description Options
AD820AN –40°C to +85°C 8-Lead Plastic Mini-DIP N-8
AD820BN* –40°C to +85°C 8-Lead Plastic Mini-DIP N-8
AD820AR –40°C to +85°C 8-Lead SOIC R-8
AD820BR –40°C to +85°C 8-Lead SOIC R-8
WARNING!
ESD SENSITIVE DEVICE
*Not for new design, obsolete April 2002.
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