Philips Magnetoresistive Sensor manual Amb MV/V 75 oC 125 oC Operating range KA/m

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Philips Semiconductors

Magnetoresistive sensors for

magnetic ﬁeld measurement

General

Figure 10 is similar to Fig.9, but with the sensor powered by a constant current supply. Figure 10 shows that, in this case, the temperature dependency of sensitivity is significantly reduced. This is a direct result of the increase in bridge resistance with temperature (see Fig.8), which

partly compensates the fall in sensitivity by increasing the voltage across the bridge and hence the output voltage. Figure 8 demonstrates therefore the advantage of operating with constant current.

75						MLC135
75
		T	=	25oC
VO		amb
VO				25	o	C
(mV/V)				25		C
(mV/V)
50
						75oC
						125oC
25
0
25
50
		operating range
75
4	2	0	2			4
				H y (kA/m)

Fig.10 Output voltage ‘Vo’ of a KMZ10B sensor as a function of transverse field ‘Hy’ for several temperatures.

2000 Sep 06

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Contents General Magnetoresistive sensors for Magnetic ﬁeld measurement ContentsOperating principles Philips SemiconductorsKMZ10 chip structure 2000 Sep Sensitivity Sensor FieldLinearize Application Package Range TypeFlipping Sensor characteristicsEffect of temperature on behaviour 25 oC Amb MV/V 75 oC 125 oC Operating range KA/m KMZ10B Using magnetoresistive sensorsFurther information for advanced users + Δ R ⎛ H 2R T For R 8 = RGiven by Positive temperature coefficient TCA1 = 1 + Magnetoresistive sensorAppendix 1 the Magnetoresistive Effect Resistance- ﬁeld relationSinφcosφ Linearization Magnetization of the thin layerSensitivity Materials 10−8Ωm Δρ/ρ% ΙΙkΔ/m MaterialsAppendix 2 Sensor Flipping This also considerably enlarges Hk. If a small temperatureSensor output ‘Vo’ as a function of the transverse ﬁeld Hy Appendix 3 Sensor Layout KMZ10 and KMZ11 bridge configuration 2000 Sep Contents Weak Field MeasurementFundamental measurement techniques Flipping coil T flipping current if Time Internal magnetization Sensor Temperature Drift 25 oC Flipping coil Sensor KMZ10A1 Technique Effect