Current Sense Amplifiers AD220570 pages

FUNCTIONAL BLOCK DIAGRAM
AD22057
OUT
GND
IN+
IN–
+VS OFS A1 A2
A1 A2
REV. A
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a Single-Supply Sensor
Interface Amplifier
AD22057
GENERAL DESCRIPTION
The AD22057 is a single-supply difference amplifier for amplifying
and low-pass filtering small differential voltages (typically
100 mV FS at a gain of 40) from sources having a large commonmode
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
FEATURES
Gain of 320. Alterable from 31 to 3160
Input CMR from Below Ground to 63 (VS – 1 V)
Output Span 20 mV to (VS – 0.2) V
1-, 2-, 3-Pole Low-Pass Filtering Available
Accurate Midscale Offset Capability
Differential Input Resistance 400 kV
Drives 1 kV Load to +4 V Using VS = +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: –408C to +1258C
APPLICATIONS
Current Sensing
Motor Control
Interface for Pressure Transducers, Position Indicators,
Strain Gages, and Other Low Level Signal Sources
Accelerometers
a +5 V supply with excellent rejection of this common-mode
voltage. This is achieved by the use of a special resistive attenuator
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.
AD22057
SINGLE-POLE LOW-PASS FILTERING, GAIN: 40
POWER
DARLINGTON
100mV 200kV
C
+5V
ANALOG OUTPUT
4V PER AMP
CORNER FREQUENCY
= 0.796Hz-mF
ANALOG GROUND
SOLENOID
LOAD
+VS (CAR BATTERY)
CMOS DRIVER
CHASSIS
Figure 1. Typical Application Circuit for a Current Sensor Interface
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