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a
AD22151
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 World Wide Web Site: http://www.analog.com
Fax: 781/326-8703 © Analog Devices, Inc., 1997
Linear Output
Magnetic Field Sensor
FUNCTIONAL BLOCK DIAGRAM
TEMP REF
I
SOURCE
DEMODSWITCHES
OUT AMP
REF
V
CC
/2
AD22151
FEATURES
Adjustable Offset to Unipolar or Bipolar Operation
Low Offset Drift Over Temperature Range
Gain Adjustable Over Wide Range
Low Gain Drift Over Temperature Range
Adjustable First Order Temperature Compensation
Ratiometric to V
CC
APPLICATIONS
Automotive
Throttle Position Sensing
Pedal Position Sensing
Suspension Position Sensing
Valve Position Sensing
Industrial
Absolute Position Sensing
Proximity Sensing
GENERAL DESCRIPTION
The AD22151 is a linear magnetic field transducer. The sensor
output is a voltage proportional to a magnetic field applied
perpendicularly to the package top surface.
The sensor combines integrated bulk Hall cell technology and
instrumentation circuitry to minimize temperature related drifts
associated with silicon Hall cell characteristics. The architecture
maximizes the advantages of a monolithic implementation while
allowing sufficient versatility to meet varied application require-
ments with a minimum number of components.
Principle features include dynamic offset drift cancellation and a
built-in temperature sensor. Designed for single +5 volt supply
operation, the AD22151 achieves low drift offset and gain op-
eration over –40°C to +150°C. Temperature compensation can
accommodate a number of magnetic materials commonly uti-
lized in economic position sensor assemblies.
The transducer may be configured for specific signal gains de-
pendent upon application requirements. Output voltage can be
adjusted from fully bipolar (reversible) field operation to fully
unipolar field sensing.
The voltage output achieves near rail-to-rail dynamic range,
capable of supplying 1 mA into large capacitive loads. The sig-
nal is ratiometric to the positive supply rail in all configurations.
NC
R1
GND
R3
R2
V
CC
AD22151NC = NO CONNECT
OUTPUT
0.1mF
Figure 1. Typical Bipolar Configuration with Low
(< –500 ppm) Compensation
NC
R1
GND
R3
R2
V
CC
AD22151NC = NO CONNECT
OUTPUT
0.1mF
R4
Figure 2. Typical Unipolar Configuration with High
(≈ –2000 ppm) Compensation