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Single Supply, Rail-to-Rail
Low Power, FET-Input Op Amp
AD824
FEATURES
Single Supply Operation: 3 V to 30 V
Very Low Input Bias Current: 2 pA
Wide Input Voltage Range
Rail-to-Rail Output Swing
Low Supply Current: 500 A/Amp
Wide Bandwidth: 2 MHz
Slew Rate: 2 V/ s
No Phase Reversal
APPLICATIONS
Photo Diode Preamplifier
Battery Powered Instrumentation
Power Supply Control and Protection
Medical Instrumentation
Remote Sensors
Low Voltage Strain Gage Amplifiers
DAC Output Amplifier
PIN CONFIGURATIONS
14-Lead Epoxy SOIC
(R Suffix)
16-Lead Epoxy SOIC
(R Suffix)
OUT A
1
–IN A
+IN A
V+
+IN B
–IN B
OUT A 1
–IN A 2
+IN A 3
V+ 4
+IN B 5
–IN B 6
OUT B 7
14 OUT D
13 –IN D
16
OUT D
15
–IN D
2
3
4
5
6
AD824
12 +IN D
14
+IN D
11 V–
TOP VIEW
(Not to Scale)
10 +IN C
9 –IN C
8 OUT C
AD824
13
V–
12
+IN C
11
–IN C
10
OUT C
9
NC
OUT B
7
NC
8
NC = NO CONNECT
GENERAL DESCRIPTION
The AD824 is a quad, FET input, single supply amplifier, fea-
turing rail-to-rail outputs. The combination of FET inputs and
rail-to-rail outputs makes the AD824 useful in a wide variety of
low voltage applications where low input current is a primary
consideration.
The AD824 is guaranteed to operate from a 3 V single supply
up to
±
15 V dual supplies. AD824AR-3V Parametric Perfor-
mance at 3 V is fully guaranteed.
Fabricated on ADI’s complementary bipolar process, the AD824
has a unique input stage that allows the input voltage to safely
extend beyond the negative supply and to the positive supply
without any phase inversion or latchup. The output voltage
swings to within 15 mV of the supplies. Capacitive loads to
350 pF can be handled without oscillation.
The FET input combined with laser trimming provides an input
that has extremely low bias currents with guaranteed offsets
below 1 mV. This enables high accuracy designs even with
high source impedances. Precision is combined with low
noise, making the AD824 ideal for use in battery powered
medical equipment.
Applications for the AD824 include portable medical equipment,
photo diode preamplifiers and high impedance transducer
amplifiers.
The ability of the output to swing rail-to-rail enables designers
to build multistage filters in single supply systems and maintain
high signal-to-noise ratios.
The AD824 is specified over the extended industrial (–40∞C to
+85∞C) temperature range and is available in narrow 14-lead
and 16-lead SOIC packages.
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 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 companies.
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.
AD824–SPECIFICATIONS
ELECTRICAL SPECIFICATIONS
(@ V = 5.0 V, V
S
CM
= 0 V, V
OUT
= 0.2 V, T
A
= 25 C unless otherwise noted)
Min
Typ
0.1
Max
1.0
1.5
12
4000
10
3.0
80
74
10
13
3.3
Unit
mV
mV
pA
pA
pA
pA
V
dB
dB
dB
W
pF
V/mV
V/mV
V/mV
V/mV
mV/∞C
V
V
V
V
mV
mV
mV
mV
mA
mA
W
dB
dB
mA
V/ms
kHz
ms
MHz
Degrees
dB
mV
p-p
nV/÷Hz
fA/÷Hz
%
Parameter
INPUT CHARACTERISTICS
Offset Voltage AD824A
Input Bias Current
Input Offset Current
Input Voltage Range
Common-Mode Rejection Ratio
Symbol
V
OS
Conditions
T
MIN
to T
MAX
I
B
T
MIN
to T
MAX
I
OS
T
MIN
to T
MAX
CMRR
V
CM
= 0 V to 2 V
V
CM
= 0 V to 3 V
T
MIN
to T
MAX
V
O
= 0.2 V to 4.0 V
R
L
= 2 kW
R
L
= 10 kW
R
L
= 100 kW
T
MIN
to T
MAX,
R
L
= 100 kW
–0.2
66
60
60
2
300
2
300
Input Impedance
Large Signal Voltage Gain
A
VO
Offset Voltage Drift
OUTPUT CHARACTERISTICS
Output Voltage High
DV
OS
/DT
V
OH
20
50
250
180
40
100
1000
400
2
4.988
4.985
4.85
4.82
15
20
120
140
±
12
±
10
100
80
500
2
150
2.5
2
50
–123
2
16
0.8
0.005
600
Output Voltage Low
V
OL
Short Circuit Limit
Open-Loop Impedance
POWER SUPPLY
Power Supply Rejection Ratio
Supply Current/Amplifier
DYNAMIC PERFORMANCE
Slew Rate
Full-Power Bandwidth
Settling Time
Gain Bandwidth Product
Phase Margin
Channel Separation
NOISE PERFORMANCE
Voltage Noise
Voltage Noise Density
Current Noise Density
Total Harmonic Distortion
I
SC
Z
OUT
PSRR
I
SY
SR
BW
P
t
S
GBP
fo
CS
e
n
p-p
e
n
i
n
THD
I
SOURCE
= 20
mA
T
MIN
to T
MAX
I
SOURCE
= 2.5 mA
T
MIN
to T
MAX
I
SINK
= 20
mA
T
MIN
to T
MAX
I
SINK
= 2.5 mA
T
MIN
to T
MAX
Sink/Source
T
MIN
to T
MAX
f = 1 MHz, A
V
= 1
V
S
= 2.7 V to 12 V
T
MIN
to T
MAX
T
MIN
to T
MAX
R
L
= 10 kW, A
V
= 1
1% Distortion, V
O
= 4 V p-p
V
OUT
= 0.2 V to 4.5 V, to 0.01%
No Load
f = 1 kHz, R
L
= 2 kW
0.1 Hz to 10 Hz
f = 1 kHz
f = 1 kHz
f = 10 kHz, R
L
= 0, A
V
= +1
4.975
4.97
4.80
4.75
25
30
150
200
70
66
–2–
REV. C
AD824
ELECTRICAL SPECIFICATIONS
(@ V =
S
15.0 V, V
OUT
= 0 V, T
A
= 25 C unless otherwise noted)
Conditions
Min
Typ
0.5
0.6
4
500
25
3
500
–15
70
66
80
10
13
3.3
12
50
300
200
50
200
2000
1000
2
14.988
14.985
14.85
14.82
–14.985
–14.98
–14.88
–14.86
±
20
100
80
560
625
675
Max
2.5
4.0
35
4000
20
13
Unit
mV
mV
pA
pA
pA
pA
pA
V
dB
dB
W
pF
V/mV
V/mV
V/mV
V/mV
mV/∞C
V
V
V
V
V
V
V
V
mA
W
dB
dB
mA
mA
V/ms
kHz
ms
MHz
Degrees
dB
mV
p-p
nV/÷Hz
fA/÷Hz
%
Parameter
INPUT CHARACTERISTICS
Offset Voltage AD824A
Input Bias Current
Symbol
V
OS
I
B
I
B
I
OS
CMRR
T
MIN
to T
MAX
V
CM
= 0 V
T
MIN
to T
MAX
V
CM
= –10 V
T
MIN
to T
MAX
Input Offset Current
Input Voltage Range
Common-Mode Rejection Ratio
Input Impedance
Large Signal Voltage Gain
V
CM
= –15 V to 13 V
T
MIN
to T
MAX
Vo = –10 V to +10 V;
R
L
= 2 kW
R
L
= 10 kW
R
L
= 100 kW
T
MIN
to T
MAX,
R
L
= 100 kW
A
VO
Offset Voltage Drift
OUTPUT CHARACTERISTICS
Output Voltage High
DV
OS
/DT
V
OH
Output Voltage Low
V
OL
Short Circuit Limit
Open-Loop Impedance
POWER SUPPLY
Power Supply Rejection Ratio
Supply Current/Amplifier
DYNAMIC PERFORMANCE
Slew Rate
Full-Power Bandwidth
Settling Time
Gain Bandwidth Product
Phase Margin
Channel Separation
NOISE PERFORMANCE
Voltage Noise
Voltage Noise Density
Current Noise Density
Total Harmonic Distortion
I
SC
Z
OUT
PSRR
I
SY
I
SOURCE
= 20
mA
T
MIN
to T
MAX
I
SOURCE
= 2.5 mA
T
MIN
to T
MAX
I
SINK
= 20
mA
T
MIN
to T
MAX
I
SINK
= 2.5 mA
T
MIN
to T
MAX
Sink/Source, T
MIN
to T
MAX
f = 1 MHz, A
V
= 1
V
S
= 2.7 V to 15 V
T
MIN
to T
MAX
V
O
= 0 V
T
MIN
to T
MAX
R
L
= 10 kW, A
V
= 1
1% Distortion, V
O
= 20 V p-p
V
OUT
= 0 V to 10 V, to 0.01%
f = 1 kHz, R
L
=2 kW
0.1 Hz to 10 Hz
f = 1 kHz
f = 1 kHz
f =10 kHz, V
O
= 3 V rms,
R
L
= 10 kW
14.975
14.970
14.80
14.75
±
8
–14.975
–14.97
–14.85
–14.8
70
68
SR
BW
P
t
S
GBP
fo
CS
e
n
p-p
e
n
i
n
THD
2
33
6
2
50
–123
2
16
1.1
0.005
REV. C
–3–
AD824–SPECIFICATIONS
ELECTRICAL SPECIFICATIONS
Parameter
INPUT CHARACTERISTICS
Offset Voltage AD824A -3 V
Input Bias Current
Input Offset Current
Input Voltage Range
Common-Mode Rejection Ratio
Input Impedance
Large Signal Voltage Gain
V
OS
T
MIN
to T
MAX
I
B
T
MIN
to T
MAX
I
OS
T
MIN
to T
MAX
CMRR
V
CM
= 0 V to 1 V
T
MIN
to T
MAX
V
O
= 0.2 V to 2.0 V
R
L
= 2 kW
R
L
= 10 kW
R
L
= 100 kW
T
MIN
to T
MAX,
R
L
= 100 kW
0
58
56
2
250
2
250
74
10
13
3.3
10
30
180
90
20
65
500
250
2
2.988
2.985
2.85
2.82
15
20
120
140
±
8
±
6
100
(@ V
S
= 3.0 V, V
CM
= 0 V, V
OUT
= 0.2 V, T
A
= 25 C unless otherwise noted)
Conditions
Min
Typ
0.2
Max
1.0
1.5
12
4000
10
1
Unit
mV
mV
pA
pA
pA
pA
V
dB
dB
W
pF
V/mV
V/mV
V/mV
V/mV
mV/∞C
V
V
V
V
mV
mV
mV
mV
mA
mA
W
dB
dB
mA
V/ms
kHz
ms
MHz
Degrees
dB
mV
p-p
nV/÷Hz
fA/÷Hz
%
Symbol
A
VO
Offset Voltage Drift
OUTPUT CHARACTERISTICS
Output Voltage High
DV
OS
/DT
V
OH
Output Voltage Low
V
OL
Short Circuit Limit
Open-Loop Impedance
POWER SUPPLY
Power Supply Rejection Ratio
Supply Current/Amplifier
DYNAMIC PERFORMANCE
Slew Rate
Full-Power Bandwidth
Settling Time
Gain Bandwidth Product
Phase Margin
Channel Separation
NOISE PERFORMANCE
Voltage Noise
Voltage Noise Density
Current Noise Density
Total Harmonic Distortion
I
SC
I
SC
Z
OUT
PSRR
I
SY
SR
BW
P
t
S
GBP
fo
CS
e
n
p-p
e
n
i
n
THD
I
SOURCE
= 20
mA
T
MIN
to T
MAX
I
SOURCE
= 2.5 mA
T
MIN
to T
MAX
I
SINK
= 20
mA
T
MIN
to T
MAX
I
SINK
= 2.5 mA
T
MIN
to T
MAX
Sink/Source
Sink/Source, T
MIN
to T
MAX
f = 1 MHz, A
V
= 1
V
S
= 2.7 V to 12 V,
T
MIN
to T
MAX
V
O
= 0.2 V, T
MIN
to T
MAX
R
L
=10 kW, A
V
= 1
1% Distortion, V
O
= 2 V p-p
V
OUT
= 0.2 V to 2.5 V, to 0.01%
f = 1 kHz, R
L
= 2 kW
0.1 Hz to 10 Hz
f = 1 kHz
f = 10 kHz, R
L
= 0, A
V
= +1
2.975
2.97
2.8
2.75
25
30
150
200
70
66
500
2
300
2
2
50
–123
2
16
0.8
0.01
600
–4–
REV. C
