a
CONNECTION DIAGRAMS
14-Lead Plastic DIP (N)
14-Lead CerDIP (Q) Packages
OUTPUT
1
–IN
2
+IN
3
+VS
4
14
4
1
AD704
OUTPUT OUTPUT
1
13
–IN
–IN
2
12
+IN
+IN
3
11
–VS
+VS
4
(TOP VIEW)
+IN
5
–IN
6
OUTPUT
7
2
3
APPLICATIONS
Industrial/Process Controls
Weigh Scales
ECG/EKG Instrumentation
Low Frequency Active Filters
16-Lead SOIC
(R) Package
1
4
AD704
16
OUTPUT
15
–IN
14
+IN
13
–VS
(TOP VIEW)
10
+IN
+IN
5
9
–IN
–IN
6
8
OUTPUT OUTPUT
NC
12
+IN
11
–IN
7
10
OUTPUT
8
9
2
3
NC
NC = NO CONNECT
OUT1
NC
OUT4
–IN4
20-Terminal LCC
(E) Package
–IN1
FEATURES
High DC Precision
75 ␮V Max Offset Voltage
1 ␮V/ⴗC Max Offset Voltage Drift
150 pA Max Input Bias Current
0.2 pA/ⴗC Typical I B Drift
Low Noise
0.5 ␮V p-p Typical Noise, 0.1 Hz to 10 Hz
Low Power
600 ␮A Max Supply Current per Amplifier
MIL-STD-883B Processing Available
Available in Tape and Reel in Accordance
with EIA-481A Standard
Dual Version: AD706
Quad Picoampere Input Current
Bipolar Op Amp
AD704
3
2
1
20
19
PRODUCT DESCRIPTION
The AD704 is an excellent choice for use in low frequency active
filters in 12- and 14-bit data acquisition systems, in precision
instrumentation, and as a high quality integrator. The AD704 is
internally compensated for unity gain and is available in five
performance grades. The AD704J and AD704K are rated over
the commercial temperature range of 0°C to 70°C. The AD704A
is rated over the industrial temperature of –40°C to +85°C. The
AD704T is rated over the military temperature range of –55°C
to +125°C and is available processed to MIL-STD-883B, Rev. C.
NC 5
AMP 1
+VS 6
NC 7
17 NC
AMP 4
16 –VS
AD704
AMP 2
AMP 3
15 NC
14 +IN3
12
13
–IN3
OUT2
11
NC
10
OUT3
9
–IN2
+IN2 8
NC = NO CONNECT
100
10
TYPICAL I B – nA
Since it has only 1/20 the input bias current of an AD OP07, the
AD704 does not require the commonly used “balancing” resistor.
Furthermore, the current noise is 1/5 that of the AD OP07 which
makes the AD704 usable with much higher source impedances.
At 1/6 the supply current (per amplifier) of the AD OP07, the
AD704 is better suited for today’s higher density circuit boards
and battery-powered applications.
18 +IN4
+IN1 4
The AD704 is a quad, low power bipolar op amp that has the
low input bias current of a BiFET amplifier but which offers a
significantly lower IB drift over temperature. It utilizes super-beta
bipolar input transistors to achieve picoampere input bias current
levels (similar to FET input amplifiers at room temperature),
while its IB typically only increases by 5× at 125°C (unlike a
BiFET amp, for which IB doubles every 10°C resulting in a
1000× increase at 125°C). Furthermore, the AD704 achieves
75 µV offset voltage and low noise characteristics of a precision
bipolar input op amp.
TYPICAL JFET AMP
1
0.1
AD704T
0.01
–55
+25
TEMPERATURE – C
+125
Figure 1. Input Bias Current Over Temperature
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.
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
© Analog Devices, Inc., 2002
AD704–SPECIFICATIONS (@ T = 25ⴗC, V
A
Parameters
INPUT OFFSET VOLTAGE
Initial Offset
Offset
vs. Temp, Average TC
vs. Supply (PSRR)
TMIN –TMAX
Long-Term Stability
Conditions
INPUT BIAS CURRENT 1
VCM = 0 V
VCM = ± 13.5 V
vs. Temp, Average TC
TMIN –TMAX
INPUT OFFSET CURRENT
vs. Temp, Average TC
TMIN –TMAX
CM
= 0 V, and ⴞ15 V dc, unless otherwise noted.)
AD704J/A
Min Typ Max
TMIN –TMAX
VS = ± 2 to ± 18 V
100
VS = ± 2.5 to ± 18 V 100
50
100
0.2
132
126
0.3
150
250
1.5
100
270
300
VCM = 0 V
VCM = ± 13.5 V
80
0.6
100
100
VCM = 0 V
VCM = ± 13.5 V
TMIN –TMAX
TMIN –TMAX
Power Supply Rejection 4
TMIN –TMAX
f = 10 Hz
RLOAD = 2 kΩ
G = –1
TMIN –TMAX
VCM = ± 13.5 V
TMIN –TMAX
75
150
1.0
80
150
200
250
300
30
0.4
80
80
300
400
30
80
112
108
80
µV
µV
µV/°C
dB
dB
µV/month
200
250
pA
pA
pA/°C
pA
pA
1.0
600
700
100
150
50
0.4
80
100
200
300
110
104
110
106
Unit
100
150
1.0
132
126
0.3
130
200
300
400
150
200
400
500
150
250
400
600
104
104
110
106
pA
pA
pA/°C
pA
pA
µV
µV
pA
pA
dB
dB
dB
dB
150
150
150
dB
0.8
0.15
0.1
0.8
0.15
0.1
0.8
0.15
0.1
MHz
V/µs
V/µs
40储2
300储2
40储2
300储2
40储2
300储2
MΩ储pF
GΩ储pF
± 13.5 ± 14
100 132
98
128
± 13.5 ± 14
114 132
108 128
0.1 to 10 Hz
f = 10 Hz
3
50
3
50
INPUT VOLTAGE NOISE
0.1 to 10 Hz
f = 10 Hz
f = 1 kHz
0.5
17
15
0.5
17
15
VO = ± 12 V
RLOAD = 10 kΩ
TMIN –TMAX
VO = ± 10 V
RLOAD = 2 kΩ
TMIN –TMAX
AD704T
Typ Max
200
300
INPUT CURRENT NOISE
OPEN-LOOP GAIN
Min
0.2
94
94
94
94
INPUT IMPEDANCE
Differential
Common-Mode
INPUT VOLTAGE RANGE
Common-Mode Voltage
Common-Mode Rejection Ratio
30
50
0.2
132
126
0.3
250
400
500
600
Input Bias Current2
Common-Mode Rejection 3
AD704K
Typ Max
300
400
TMIN –TMAX
FREQUENCY RESPONSE
UNITY GAIN
Crossover Frequency
Slew Rate, Unity Gain
Slew Rate
112
108
0.3
VCM = 0 V
VCM = ± 13.5 V
MATCHING CHARACTERISTICS
Offset Voltage
Crosstalk5
Min
22
± 13.5 ± 14
110 132
108 128
V
dB
dB
3
50
2.0
0.5
17
15
22
pA p-p
fA/√Hz
2.0
22
µV p-p
nV/√Hz
nV/√Hz
200
150
2000
1500
400
300
2000
1500
400
300
2000
1500
V/mV
V/mV
200
150
1000
1000
300
200
1000
1000
200
100
1000
1000
V/mV
V/mV
–2–
REV. C
AD704
Parameters
OUTPUT CHARACTERISTICS
Voltage Swing
Current
CAPACITIVE LOAD
Drive Capability
Conditions
RLOAD = 10 kΩ
TMIN –TMAX
Short Circuit
Min
± 13
± 13
Gain = 1
POWER SUPPLY
Rated Performance
Operating Range
Quiescent Current
TRANSISTOR COUNT
AD704J/A
Min Typ Max
± 14
± 15
10,000
± 2.0
± 15
TMIN –TMAX
1.5
1.6
# of Transistors
180
–3–
± 14
± 15
Min
± 13
10,000
± 18
2.4
2.6
± 2.0
NOTES
1
Bias current specifications are guaranteed maximum at either input.
2
Input bias current match is the maximum difference between corresponding inputs of all four amplifiers.
3
CMRR match is the difference of ∆VOS/∆VCM between any two amplifiers, expressed in dB.
4
PSRR match is the difference between ∆VOS/∆V SUPPLY for any two amplifiers, expressed in dB.
5
See Figure 2a for test circuit.
All min and max specifications are guaranteed.
Specifications subject to change without notice.
REV. C
AD704K
Typ Max
± 15
1.5
1.6
180
± 18
2.4
2.6
± 2.0
AD704T
Typ Max
Unit
± 14
± 15
V
mA
10,000
pF
± 15
1.5
1.6
180
± 18
2.4
2.6
V
V
mA
mA
AD704
ABSOLUTE MAXIMUM RATINGS 1
9k⍀
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 18 V
Internal Power Dissipation (25°C) . . . . . . . . . . . . See Note 2
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± VS
Differential Input Voltage3 . . . . . . . . . . . . . . . . . . . . . . . ± 0.7 V
Output Short-Circuit Duration (Single Input) . . . . . Indefinite
Storage Temperature Range
Q . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to +150°C
N, R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to +125°C
Operating Temperature Range
AD704J/K . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C
AD704A . . . . . . . . . . . . . . . . . . . . . . . . . . . –40°C to +85°C
AD704T . . . . . . . . . . . . . . . . . . . . . . . . . –55°C to +125°C
Lead Temperature Range (Soldering 10 seconds) . . . . . 300°C
1k⍀
OUTPUT
1/4
NOTES
1
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.
2
Specification is for device in free air:
14-Lead Plastic Package: θJA = 150°C/W
14-Lead Cerdip Package: θJA = 110°C/W
16-Lead SOIC Package: θJA = 100°C/W
20-Terminal LCC Package: θJA = 150°C/W
3
The input pins of this amplifier are protected by back-to-back diodes. If the
differential voltage exceeds ± 0.7 volts, external series protection resistors should
be added to limit the input current to less than 25 mA.
0.1␮F
1␮F
0.1␮F
1␮F
COM
AD704
INPUT*
SIGNAL
1k⍀
AD704
PIN 4
+VS
–
+
2.5k⍀
AD704
PIN 11
–VS
ALL 4 AMPLIFIERS ARE CONNECTED AS SHOWN
*THE SIGNAL INPUT (SUCH THAT THE AMPLIFIER’S OUTPUT IS AT MAX
AMPLITUDE WITHOUT CLIPPING OR SLEW LIMITING) IS APPLIED TO ONE
AMPLIFIER AT A TIME. THE OUTPUTS OF THE OTHER THREE AMPLIFIERS
ARE THEN MEASURED FOR CROSSTALK.
Figure 2a. Crosstalk Test Circuit
–80
AMP4
CROSSTALK – dB
–100
AMP2
AMP3
–120
–140
–160
10
100
1k
10k
100k
FREQUENCY – Hz
Figure 2b. Crosstalk vs. Frequency
ORDERING GUIDE
Model
Temperature Range
Package Description
Package Option
AD704JN
AD704JR
AD704JR-/REEL
AD704KN*
AD704AN*
AD704AR
AD704AR-REEL
AD704SE/883B
AD704TQ/883B*
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
–40°C to +85°C
–55°C to +125°C
–55°C to +125°C
Plastic
Small Outline (SOIC)
N-14
R-16
Tape and Reel
N-14
N-14
R-16
Tape and Reel
E-20A
Q-14
Plastic
Plastic
Small Outline (SOIC)
Leadless Ceramic Chip Carrier
Cerdip
Chips are also available.
*Not for new designs; obsolete April 2002.
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 AD704 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.
–4–
WARNING!
ESD SENSITIVE DEVICE
REV. C