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 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.
AD8225
Precision Gain of 5
Instrumentation Amplifier
FEATURES
No External Components Required
Highly Stable, Factory Trimmed Gain of 5
Low Power, 1.2 mA Max Supply Current
Wide Power Supply Range (1.7 V to 18 V)
Single- and Dual-Supply Operation
Excellent Dynamic Performance
High CMRR
86 dB Min @ DC
80 dB Min to 10 kHz
Wide Bandwidth
900 kHz
4 V to 36 V Single Supply
High Slew Rate
5 V/s Min
Outstanding DC Precision
Low Gain Drift
5 ppm/C Max
Low Input Offset Voltage
150 V Max
Low Offset Drift
2 V/C Max
Low Input Bias Current
1.2 nA Max
APPLICATIONS
Patient Monitors
Current Transmitters
Multiplexed Systems
4 to 20 mA Converters
Bridge Transducers
Sensor Signal Conditioning
FUNCTIONAL BLOCK DIAGRAM
8
7
6
5
1
2
3
4
NC = NO CONNECT
NC
–IN
+IN
–V
S
NC
+V
S
V
OUT
REF
AD8225
GENERAL DESCRIPTION
The AD8225 is an instrumentation amplifier with a fixed gain
of 5, which sets new standards of performance. The superior
CMRR of the AD8225 enables rejection of high frequency
common-mode voltage (80 dB Min @ 10 kHz). As a result,
higher ambient levels of noise from utility lines, industrial
equipment, and other radiating sources are rejected. Extended
CMV range enables the AD8225 to extract low level differential
signals in the presence of high common-mode dc voltage levels
even at low supply voltages.
Ambient electrical noise from utility lines is present at 60 Hz
and harmonic frequencies. Power systems operating at 400 Hz
create high noise environments in aircraft instrument clusters.
Good CMRR performance over frequency is necessary if power
system generated noise is to be rejected. The dc to 10 kHz
FREQUENCY – Hz
140
1 100k10
CMRR – dB
100 1k 10k
130
120
110
100
90
80
70
60
50
40
30
HIGH PERFORMANCE IN AMP
@ GAIN OF 5
AD8225
Figure 1. Typical CMRR vs. Frequency
CMRR performance of the AD8225 rejects noise from utility
systems, motors, and repair equipment on factory floors, switch-
ing power supplies, and medical equipment.
Low input bias currents combined with a high slew rate of 5 V/µs
make the AD8225 ideally suited for multiplexed applications.
The AD8225 provides excellent dc precision, with maximum
input offset voltage of 150 µV and drift of 2 µV/°C. Gain drift is
5ppm/°C or less.
Operating on either single or dual supplies, the fixed gain of 5
and wide input common-mode voltage range make the AD8225
well suited for patient monitoring applications.
The AD8225 is packaged in an 8-lead SOIC package and is
specified over the standard industrial temperature range, –40°C
to +85°C.
