1998 Mar 24

2

Philips Semiconductors

Preliminary specification

Magnetic field sensor

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

SYMBOL

DESCRIPTION

1

flip coil

bridge supply voltage

3

GND

ground

4

n.c.

not connected

5

n.c.

not connected

6

−V

O

bridge output voltage

bridge output voltage

8

−I

flip

flip coil

Fig.1 Simplified outline.

handbook, halfpage

4

1

5

8

MGD791

pin 1

index

H

QUICK REFERENCE DATA

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”.

SYMBOL

PARAMETER

MIN.

TYP.

MAX.

UNIT

bridge supply voltage

−

58V

S

sensitivity (uncompensated)

12

16

−

offset voltage

−1.5

−

+1.5

mV/V

bridge resistance

1

−

3k

Ω

flip coil resistance

1

3

5

Ω

minimum recommended flipping current; note 1

800

1000

1200

mA

minimum flip pulse duration; note 1

1

3

100

µs

mV V

⁄

kA m

⁄

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