ATS674 Allegro MicroSystems, ATS674 Datasheet - Page 14

• Manufacturer Part Number: ATS674
• Description: (ATS673 / ATS674) Self-Calibrating TPOS Gear Tooth Sensor Optimized
• Manufacturer: Allegro MicroSystems

ATS673 and
ATS674
Magnetic Profile
In order to establish the proper operating specification for a par-
ticular sensor device and target system, a systematic evaluation
of the magnetic circuit should be performed. The first step is the
generation of a magnetic map of the target. By using a calibrated
device, a magnetic profile of the system is made. Figure 10 is a
magnetic map of the 8X reference target.
Self-Calibrating TPOS Gear Tooth Sensor Optimized
1600
1400
1200
1000
1300
1200
1100
1000
800
600
400
200
900
800
700
600
500
400
300
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100
Figure 10. Magnetic Data for the 8X Reference Target and SE package.
0
0
0
0
Air Gap Versus Magnetic Field, Reference Target 8X with SE Package
Sensor and Target Evaluation
Tooth
Valley
Magnetic Map, Reference Target 8X with SE Package
1.0
60
for Automotive Cam Sensing Applications
120
2.0
Target Rotation (°)
AG (mm)
180
3.0
A pair of curves can be derived from this map data, and be used
to describe the tooth and valley magnetic field strength, B, versus
the size of the air gap, AG. This allows determination of the mini-
mum amount of magnetic flux density that guarantees operation
of the sensor, so the system designer can determine the maximum
allowable AG for the sensor and target system. One can also
determine the TPOS air gap capabilities of the sensor by compar-
ing the minimum tooth signal to the maximum valley signal.
240
4.0
300
5.0
115 Northeast Cutoff, Box 15036
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com
360
6.0
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