1998 Mar 24

2

Philips Semiconductors

Product specification

Magnetic field sensor

KMZ51

FEATURES

• High sensitivity

• Integrated compensation coil

• Integrated set/reset coil.

APPLICATIONS

• Navigation

• Current and earth magnetic field measurement

• Traffic detection.

DESCRIPTION

The KMZ51 is an extremely sensitive magnetic field

sensor, employing the magnetoresistive effect of thin-film

permalloy. The sensor contains one magnetoresistive

Wheatstone bridge and integrated compensation and

set/reset conductors. The integrated compensation

conductor allows magnetic field measurement with current

feedback loops to generate an output that is independent

of drift in sensitivity. 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

compensation coil

5

−I

comp

compensation coil

6

bridge output voltage

bridge output voltage

8

−I

flip

flip coil

Fig.1 Simplified outline.

handbook, halfpage

4

1

5

8

MGD827

pin 1

index

Hext

QUICK REFERENCE DATA

Notes

2. 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

compensation coil resistance

100

170

300

Ω

compensation coil field factor; note 1

19

22

25

A/m/mA

flip coil resistance

1

3

5

Ω

minimum recommended flipping current; note 2

800

1000

1200

mA

minimum flip pulse duration; note 2

1

3

100

µs

mV V

⁄

kA m

⁄

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