a
FEATURES
Gain of 20. Alterable from 1 to 160
Input CMR from Below Ground to 6 (V
S
– 1 V)
Output Span 20 mV to (V
S
– 0.2) V
1-, 2-, 3-Pole Low-Pass Filtering Available
Accurate Midscale Offset Capability
Differential Input Resistance 400 k
Drives 1 k Load to +4 V Using V
S
= +5 V
Supply Voltage: +3.0 V to +36 V
Transient Spike Protection and RFI Filters Included
Peak Input Voltage (40 ms): 60 V
Reversed Supply Protection: –34 V
Operating Temperature Range: –40 C to +125 C
APPLICATIONS
Current Sensing
Motor Control
Interface for Pressure Transducers, Position Indicators,
Strain Gages, and Other Low Level Signal Sources
Accelerometers
Single-Supply Sensor
Interface Amplifier
AD22057
FUNCTIONAL BLOCK DIAGRAM
+V
S
OFS
A1
A2
AD22057
IN+
A1
IN–
A2
OUT
GND
GENERAL DESCRIPTION
The AD22057 is a single-supply difference amplifier for ampli-
fying and low-pass filtering small differential voltages (typically
100 mV FS at a gain of 40) from sources having a large common-
mode voltage.
Supply voltages from +3.0 V to +36 V can be used. The input
common-mode range extends from below ground to +24 V using
a +5 V supply with excellent rejection of this common-mode
voltage. This is achieved by the use of a special resistive attenua-
tor at the input, laser trimmed to a very high differential balance.
Provisions are included for optional low-pass filtering and gain
adjustment. An accurate midscale offset feature allows bipolar
signals to be amplified.
+V
S
(CAR BATTERY)
SOLENOID
LOAD
+5V
ANALOG OUTPUT
4V PER AMP
100m
AD22057
200k
CMOS DRIVER
C
CORNER FREQUENCY
= 0.796Hz- F
CHASSIS
POWER
DARLINGTON
SINGLE-POLE LOW-PASS FILTERING, GAIN: 40
ANALOG GROUND
Figure 1. Typical Application Circuit for a Current Sensor Interface
REV. A
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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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© Analog Devices, Inc., 1999
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