Single-Supply Sensor
a
Interface Amplifier
AD22057
FEATURES FUNCTIONAL BLOCK DIAGRAM
Gain of 320. Alterable from 31 to 3160
Input CMR from Below Ground to 63 (V 1 V)
S +V
OFS A1 A2
S
Output Span 20 mV to (V 0.2) V
S
1-, 2-, 3-Pole Low-Pass Filtering Available
AD22057
Accurate Midscale Offset Capability
Differential Input Resistance 400 kV
IN+
A1
A2 OUT
Drives 1 kV Load to +4 V Using V = +5 V
S
IN
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
GND
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
GENERAL DESCRIPTION a +5 V supply with excellent rejection of this common-mode
The AD22057 is a single-supply difference amplifier for ampli- voltage. This is achieved by the use of a special resistive attenua-
fying and low-pass filtering small differential voltages (typically tor at the input, laser trimmed to a very high differential balance.
100 mV FS at a gain of 40) from sources having a large common-
Provisions are included for optional low-pass filtering and gain
mode voltage.
adjustment. An accurate midscale offset feature allows bipolar
Supply voltages from +3.0 V to +36 V can be used. The input signals to be amplified.
common-mode range extends from below ground to +24 V using
+V (CAR BATTERY)
S
+5V
SOLENOID
LOAD
ANALOG OUTPUT
4V PER AMP
100mV 200kV
AD22057
CORNER FREQUENCY
= 0.796Hz-mF
CMOS DRIVER
C
POWER
ANALOG GROUND
DARLINGTON
CHASSIS
SINGLE-POLE LOW-PASS FILTERING, GAIN: 40
Figure 1. Typical Application Circuit for a Current Sensor Interface
REV. B Document Feedback
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
use, nor for any infringements of patents or other rights of third parties
Tel: 781.329.4700 201 7 Analog Devices, Inc. All rights reserved.
which may result from its use. No license is granted by implication or
www.analog.com
otherwise under any patent or patent rights of Analog Devices. Technical Support (T = +258C, V = +5 V, V = 0, R = 10 kV unless otherwise noted)
AD22057SPECIFICATIONS
A S CM L
Parameter Comments Test Conditions Min Typ Max Units
INPUTS (PINS 1 AND 8)
+CMR Positive Common-Mode Range T = T to T +24 V
A MIN MAX
CMR Negative Common-Mode Range T = T to +85 C 1.0 V
A MIN
CMRR Common-Mode Rejection Ratio f 10 Hz 80 90 dB
LF
CMRR Common-Mode Rejection Ratio f = 1 kHz 80 90 dB
HF
R Common-Mode Input Resistance Pin 1 or Pin 8 to Pin 2 180 240 300 kW
INCM
R Matching of Resistances 0.5 %
MATCH
R Differential Input Resistance Pin 1 to Pin 8 280 400 kW
INDIFF
PREAMPLIFIER
1
G Closed-Loop Gain 9.7 10.0 10.3 V/V
CL
V Output Voltage Range (Pin 3) +0.01 +4.8 V
O
2
R Output Resistance 97 100 103 kW
O
OUTPUT BUFFER
1
G Closed-Loop Gain R 10 kW 1.94 2.0 2.06 V/V
CL LOAD
3
V Output Voltage Range +0.02 +4.8 V
O
R Output Resistance (Pin 5) V 0.1 V dc 2.0 W
O O
OVERALL SYSTEM
1
G Gain V 0.1 V dc 19.9 20.0 20.1 V/V
O
Gain Drift T = T to T 62.5 +62.5 ppm/ C
A MIN MAX
4
V Input Offset Voltage 1 0.03 1 mV
OS
Offset Drift T = T to T 12.5 +12.5 m V/ C
A MIN MAX
OFS Midscale Offset (Pin 7) Scaling 0.49 0.50 0.51 V/V
Input Resistance Pin 7 to Pin 2 2.5 3.0 kW
I Short-Circuit Output Current 7 11 25 mA
OSC
T = T to T 527mA
A MIN MAX
BW 3 dB Bandwidth V = +1 V dc 20 30 kHz
3 dB O
SR Slew Rate 0.2 V/m s
4
N Noise Spectral Density f = 100 Hz to 10 kHz 0.2 m V/ Hz
SD
PSR Power Supply Rejection V = 5 V, V = 1 V to 4.2 V
S O
V = 24 V, V = 1 V to 22 V
S O
T = T to T
A MIN MAX
4
V Input Offset Voltage 20.0 m V/V
OS
G Gain 0.05 %/V
POWER SUPPLY
V Operating Range T = T to T 35 36 V
S A MIN MAX
5
I Quiescent Supply Range T = +25 C, V = +5 V 200 500 m A
S A S
TEMPERATURE RANGE
T Operating Temperature Range 40 +125 C
OP
AD22057RZ
PACKAGE 8-Lead SOIC (R-8)
NOTES
1
Specified for default mode i.e., with no external components. The overall gain is trimmed to 0.5% while the individual gains of A1 and A2 may be subject to a
maximum 3% tolerance. Note that the actual gain in a particular application can be modified by the use of external resistor networks.
2
The actual output resistance of A1 is only a few ohms, but access to this output, via Pin 3, is always through a 100 k W resistor, which is trimmed to 3%.
3
For V 20 V. For V > 20 V, V . 1 mV/V V .
CM CM OL CM
4
Referred to the input (Pins 1 and 8).
5
With V = 0 V. Differential mode signals are referred to as V , while V refers to common-mode voltages.
DM DM CM
Specifications subject to change without notice.
REV. B
2