AD704 Datasheet, PDF (1/8 Pages) Analog Devices – Quad Picoampere Input Current Bipolar Op Amp

a
Quad Picoampere Input Current
Bipolar Op Amp
AD704
FEATURES
High DC Precision
75 ␮V max Offset Voltage
1 ␮V/؇C max Offset Voltage Drift
150 pA max Input Bias Current
0.2 pA/؇C 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
Chips & MIL-STD-883B Processing Available
Available in Tape and Reel in Accordance
with EIA-481A Standard
Single Version: AD705, Dual Version: AD706
PRIMARY APPLICATIONS
Industrial/Process Controls
Weigh Scales
ECG/EKG Instrumentation
Low Frequency Active Filters
CONNECTION DIAGRAMS
14-Pin Plastic DIP (N)
14-Pin Cerdip (Q) Packages
16-Pin SOIC
(R) Package
OUTPUT 1
–IN 2
+ IN 3
+VS ₄
+ IN 5
–IN 6
OUTPUT 7
1
4
AD704
(TOP VIEW)
2
3
14 OUTPUT
13 –IN
12 + IN
11 –VS
10 + IN
9 –IN
8 OUTPUT
OUTPUT 1
–IN 2
1
4
+ IN ₃
+VS 4
+ IN 5
AD704
(TOP VIEW)
–IN 6
2
3
OUTPUT 7
NC 8
NC = NO CONNECT
16 OUTPUT
15 –IN
14 + IN
13 –V_S
12 + IN
11 –IN
10 OUTPUT
9 NC
(E) Package ^{20-Terminal LCC}
PRODUCT DESCRIPTION
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 I_B drift over temperature. It utilizes Super-
beta bipolar input transistors to achieve picoampere input bias
current levels (similar to FET input amplifiers at room tempera-
ture), while its I_B typically only increases 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). Furthermore the AD704
achieves 75 µV offset voltage and low noise characteristics of a
precision bipolar input op amp.
+IN1 4
NC 5
+V_{S 6}
NC 7
+IN2 8
3 2 1 20 19
AMP 1 AMP 4
AD704
AMP 2 AMP 3
18 +IN4
17 NC
16 –V_S
15 NC
14 +IN3
9 10 11 12 13
NC = NO CONNECT
100
10
TYPICAL JFET AMP
1
0.1
AD704T
0.01
–55
+25
+125
TEMPERATURE – °C
Figure 1. Input Bias Current Over Temperature
REV. A
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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
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.
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 and AD704B are 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.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
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