Single Supply, Rail-to-Rail, Low Cost
Instrumentation Amplifier
a
AD623
FEATURES
Easy to Use
Higher Performance than Discrete Design
Single and Dual Supply Operation
Rail-to-Rail Output Swing
CONNECTION DIAGRAM
8-Lead Plastic DIP (N),
SOIC (R) and SOIC (RM) Packages
Input Voltage Range Extends 150 mV Below Ground
(Single Supply)
Low Power, 575 A Max Supply Current
Gain Set with One External Resistor
Gain Range 1 (No Resistor) to 1,000
1
2
3
4
8
7
6
5
؉R
؉V
؊R
G
G
؊IN
؉IN
S
OUTPUT
؊V
REF
S
AD623
HIGH ACCURACY DC PERFORMANCE
0.1% Gain Accuracy (G = 1)
0.35% Gain Accuracy (G > 1)
25 ppm Gain Drift (G = 1)
200 V Max Input Offset Voltage (AD623A)
2 V/؇C Max Input Offset Drift (AD623A)
100 V Max Input Offset Voltage (AD623B)
1 V/؇C Max Input Offset Drift (AD623B)
25 nA Max Input Bias Current
common-mode range and can amplify signals that have a
common-mode voltage 150 mV below ground. Although the
design of the AD623 has been optimized to operate from a single
supply, the AD623 still provides superior performance when
operated from a dual voltage supply (±2.5 V to ±6.0 V).
NOISE
35 nV/√Hz RTI Noise @ 1 kHz (G = 1)
EXCELLENT AC SPECIFICATIONS
90 dB Min CMRR (G = 10); 84 dB Min CMRR (G = 5)
(@ 60 Hz, 1K Source Imbalance)
800 kHz Bandwidth (G = 1)
20 s Settling Time to 0.01% (G = 10)
Low power consumption (1.5 mW at 3 V), wide supply voltage
range, and rail-to-rail output swing make the AD623 ideal for
battery powered applications. The rail-to-rail output stage maxi-
mizes the dynamic range when operating from low supply volt-
ages. The AD623 replaces discrete instrumentation amplifier
designs and offers superior linearity, temperature stability and
reliability in a minimum of space. Until the AD623, this level of
instrumentation amplifier performance has not been achieved.
APPLICATIONS
Low Power Medical Instrumentation
Transducer Interface
Thermocouple Amplifier
Industrial Process Controls
Difference Amplifier
120
110
Low Power Data Acquisition
100
90
x1000
PRODUCT DESCRIPTION
x100
The AD623 is an integrated single supply instrumentation am-
plifier that delivers rail-to-rail output swing on a single supply
(+3 V to +12 V supplies). The AD623 offers superior user flex-
ibility by allowing single gain set resistor programming, and
conforming to the 8-lead industry standard pinout configura-
tion. With no external resistor, the AD623 is configured for
unity gain (G = 1) and with an external resistor, the AD623 can
be programmed for gains up to 1,000.
80
70
60
50
40
30
x10
x1
The AD623 holds errors to a minimum by providing superior
AC CMRR that increases with increasing gain. Line noise, as
well as line harmonics, will be rejected since the CMRR re-
mains constant up to 200 Hz. The AD623 has a wide input
1
100k
10
100
1k
10k
FREQUENCY – Hz
Figure 1. CMR vs. Frequency, +5 VS, 0 VS
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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
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Tel: 781/329-4700
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© Analog Devices, Inc., 1999