Picoampere Input Current Quad
Bipolar Op Amp
AD704
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. Specifications subject to change without notice. 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: 781.461.3113 ©2001-2010 Analog Devices, Inc. All rights reserved.
FEATURES
High dc precision
150 µV maximum offset voltage
1.5 µV/°C maximum offset voltage drift
270 pA maximum input bias current
0.3 pA/°C typical I
B
drift
Low noise: 0.5 µV p-p
Typical noise: 0.1 Hz to 10 Hz
Low power: 600 µA maximum supply current per amplifier
Dual version: AD706
APPLICATIONS
Industrial/process controls
Weigh scales
ECG/EKG instrumentation
Low frequency active filters
GENERAL DESCRIPTION
The AD704 is a quad, low power bipolar op amp that has the
low input bias current of a BiFET amplifier and offers a signifi-
cantly lower I
B
drift over temperature. It uses superbeta bipolar
input transistors to achieve picoampere input bias current levels
(similar to FET input amplifiers at room temperature), while its
I
B
typically increases only by 5× at 125°C (unlike a BiFET amp,
for which I
B
doubles every 10°C, resulting in a 1000× increase at
125°C). In addition, the AD704 achieves 150 μV offset voltage and
the low noise characteristics of a precision bipolar input op amp.
Because it has only 1/20 the input bias current of an OP07, the
AD704 does not require the commonly used balancing resistor.
Furthermore, the current noise is 1/5 that of the OP07, which
makes the AD704 usable with much higher source impedances.
At 1/6 the supply current (per amplifier) of the OP07, the
AD704 is better suited for today’s higher density circuit boards
and battery-powered applications.
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 stability. The AD704J is
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 AD704S is rated over the military temperature
range of −55°C to +125°C, processed to MIL-STD-883B.
CONNECTION DIAGRAMS
OUTPUT
1
–IN
2
+IN
3
+V
S
4
OUTPUT
14
–IN
13
+IN
12
–V
S
11
+IN
5
–IN
6
OUTPUT
7
+IN
10
–IN
9
OUTPUT
8
1 4
2 3
AD704
TOP VIEW
(Not to Scale)
00818-001
OUTPUT
1
–IN
2
+IN
3
+V
S
4
OUTPUT
16
–IN
15
+IN
14
–V
S
13
+IN
5
–IN
6
OUTPUT
7
8
+IN
12
–IN
11
OUTPUT
NC
NC
10
9
1 4
2 3
AD704
TOP VIEW
(Not to Scale)
NC = NO CONNECT
00818-002
Figure 1. 14-Lead Plastic DIP (N) Figure 2. 16-Lead SOIC (R) Package
4
+IN1
5
NC
6
+V
S
7
NC
8
+IN2
NC = NO CONNECT
18
+IN4
17
NC
16
–V
S
15
NC
14
+IN3
13
–IN3
12
OUT3
11
NC
10
OUT2
9
1920123
–IN2
–IN4
OUT4
NC
OUT1
–IN1
1 4
2 3
AD704
TOP VIEW
(Not to Scale)
00818-003
Figure 3. 20-Terminal LCC
(E-20-1) Package
100
10
1
0.1
0.01
–55 25 125
TEMPERATURE (°C)
TYPICAL I
B
(nA)
TYPICAL JFET AMP
AD704
00818-004
Figure 4. Input Bias Current Over Temperature
Table 1. Low I
B
@ 125°C
Model 30V 16V 1.3 to 5V Next Generation
Single N/A AD8663 AD8603 N/A
Dual AD706 AD8667 AD8607 AD8622
Quad AD704 AD8669 AD8609 AD8624
