iC-MZ
DIFFERENTIAL HALL SWITCH
Rev A2, Page 6/11
DEFINITION OF MAGNETIC FIELDS AND SENSOR OUTPUT SIGNALS
In essence iC-MZ is non-magnetic and thus has prac-
tically no effect on the magnetic field to be scanned.
The Hall sensors on the topside of the chip or at pack-
age level (x, y) are sensing the z component H
z
of the
magnetic field vector at the site of each sensor.
Magnetic field component H
z
counts as a positive
when the field lines emerge on the printed upper side
of the chip.
The source of the magnetic field (magnets, coils) can
be placed above or below (back bias) the iC package.
In accordance with Figure 2 a distinction can be made
between the different position and polarity of a mag-
net from the sign of the sensor signal. Following the
amplification of the Hall voltage difference a differen-
tial analog signal V(A) or V(NA) is available at pins A
and NA with a mean voltage of Vdc (Figure 3).
If
∆H
exceeds a limit of H
t,hi
, digital output D switches
to high. If
∆H
undershoots a threshold of H
t,lo
, output
D is switched back to low. The switching status com-
plementary to D is available at output ND.
If differential field strength
∆H
lies within the H
t,lo
..H
t,hi
interval, the momentary switching status of the driver
outputs does not change.
+B
N
S
M
Z
V
N
S
z
y
M
Z
+B
V(A)
Vdc
x
V(NA)
Figure 1: Example magnet positions in relation to
iC-MZ
The difference
∆H
between z components H
1
and H
2
of the magnetic field strengths at the site of the two
Hall sensors S1 and S2 is significant for the electrical
output signal.
0
H
Figure 3: Analog signals A and NA as a function of
the difference in field strength
∆H
∆H
=
H
1
−
H
2
V(D)
H
t,hys
= H
t,hi
– H
t,lo
S
N
N
S
VB
M
Z
H
1
S2
Pin 1
S1
Pin 1
z
y
M
Z
S1
H
1
S2
H
2
H>0
H
2
H<0
H
t,lo
0
H
t,hi
H
x
Figure 2: Definition of the difference in field strength
∆H
Figure 4: Digital output D in dependence on the dif-
ference in field strength
∆H
ICHAUS [ IC-HAUS GMBH ]
