Philips Semiconductors
Magnetic field sensor
Preliminary specification
KMZ50
FEATURES
• High sensitivity
• Integrated set/reset coil.
APPLICATIONS
• Navigation
• Current and earth magnetic field measurement
• Traffic detection.
DESCRIPTION
The KMZ50 is an extremely sensitive magnetic field
sensor, employing the magnetoresistive effect of thin-film
permalloy. The sensor contains one magnetoresistive
Wheatstone bridge and integrated set/reset conductors.
With the integrated set/reset conductor the orientation of
sensitivity may be set or changed (flipped). A short current
pulse on this conductor is needed to recover (set) the
sensor after exposure to strong disturbing magnetic fields.
A negative current pulse will reset the sensor to reversed
sensitivity. By use of periodically alternated flipping pulses
and a lock-in amplifier, output will become independent of
sensor and amplifier offset.
PINNING
PIN
1
2
3
4
5
6
7
8
SYMBOL
+Iflip
VCC
GND
n.c.
n.c.
−VO
+VO
−Iflip
DESCRIPTION
flip coil
bridge supply voltage
ground
not connected
not connected
bridge output voltage
bridge output voltage
flip coil
handbook, halfpage
8
5
H
pin 1
index 1
4 MGD791
Fig.1 Simplified outline.
QUICK REFERENCE DATA
SYMBOL
PARAMETER
MIN.
TYP.
MAX.
UNIT
VCC
bridge supply voltage
S
sensitivity (uncompensated)
−
5
8
12
16
−
V
m-k---A--V----⁄-⁄--m-V--
Voffset
Rbridge
Rflip
Iflip (min)
tflip (min)
offset voltage
−1.5
bridge resistance
1
flip coil resistance
1
minimum recommended flipping current; note 1 800
minimum flip pulse duration; note 1
1
−
−
3
1 000
3
+1.5
3
5
1 200
100
mV/V
kΩ
Ω
mA
µs
Note
1. Average power consumption in flip conductor, defined by current, pulse duration and pulse repetition rate may not
exceed the specified limit, see “Limiting values”.
1998 Mar 24
2