A1351 Datasheet, PDF (23/24 Pages) Allegro MicroSystems – High Precision Linear Hall Effect Sensor IC with a Push/Pull, Pulse Width Modulated Output

A1351
High Precision Linear Hall Effect Sensor IC
with a Push/Pull, Pulse Width Modulated Output
Flux Density per Ampere vs. Gap for a Feedthrough Sensor
14
12
10
8
6
4
2
0
0.5
1
1.5
2
2.5
3
3.5
Gap (mm)
The flux density measured by the A1351 SIP is related to the
size of the gap cut into the core. The larger the gap in the core,
the smaller the flux density per ampere of applied current (see
figure 8).
Figure 9 depicts the magnetic flux density through the center of
the SIP as a function of SIP to core alignment. Note that a core
with a larger cross-sectional area would reduce the attenuation
in flux density that results from any SIP misalignment. The flat
portion of the curve in figure 9 would span a larger distance in
millimeters if the cross-sectional area of the core were increased.
Figure 8. The flux density per ampere measured by the A1351 Hall device
is related to the core gap, as shown. This figure assumes that the current
sensing application is constructed using the example setup.
Wire
Ring concentrator
Magnetic flux in gap
Measurement plane
(midplane of gap)
7.0
Interior side of
Exterior side of
6.5
Concentrator
Concentrator
6.0
5.5
5.0
4.5
4.0
3.5
+B
3.0
–2.0
–1.0
0
1.0
2.0
–2 0 2
mm
Radial Displacement from Concentrator Centerline (mm)
Figure 9. Side view of example current-conducting wire and split ring concentrator (left), and
magnetic profile (right) through the midplane of the gap in the split ring concentrator. The flux
denisty through the center of the gap varies between the inside and the outside of the gap.
Allegro MicroSystems, Inc.
22
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com