Differential Magnetoresistive Sensor FP 212 D 250-22 Version 2.0 Features • • • • High output voltage High operating temperature Robust plastic housing Signal amplitude is speed independent • Biasing magnet build in • Marking green Typical applications • Detection of speed • Detection of position • Detection of sense of rotation • Angle encoder • Linear position sensing Dimensions in mm Type Ordering Code FP 212 D 250-22 Q65212-D2504 The differential magnetoresistive sensor FP 212 D 250-22 consists of two series coupled magneto resistors (D-type InSb/NiSb semiconductor resistors whose value can be magnetically controlled) which are mounted onto an insulated ferrite substrate. The sensor is encapsulated in a plastic package and has three connecting terminals. The basic resistance of the total system is 2 × 250 Ω. A permanent magnet which supplies a biasing magnetic field is fixed on the base of the sensor. Data Sheet 1 2000-07-01 FP 212 D 250-22 Absolute Maximum Ratings Parameter Symbol Limit Values Unit Operating temperature TA Tstg Ptot VIN VI – 40/ + 140 °C – 40/ + 150 °C 450 mW 10 V > 60 V GthA ≥5 mW/K VIN N R1-3 5 V 1000…1600 Ω M V0 ≤ 10 % ≤ 130 mV Open circuit output voltage5) (at VIN N and δ = 0.2 mm) Vout pp > 1100 mV Cut-off frequency fc > 20 kHz Storage temperature Power dissipation1) Supply voltage2) Insulation voltage between terminals and magnet Thermal conductivity (when soldered) Electrical Characteristics (TA = 25 °C) Nominal supply voltage Total resistance, (δ = ∞, I ≤ 1 mA) air gap (δ = ∞) Center symmetry3) (δ = ∞) Offset voltage4) (at VIN N and δ = ∞) Measuring Arrangements By approaching a soft iron part close to the sensor a change in its resistance is obtained. The potential divider circuit of the magneto resistor causes a reduction in the temperature dependence of the output voltage VOUT. 1) Corresponding to diagram Ptot = f(TA) 2) Corresponding to diagram VIN = f(TA) 3) R1 – 2 – R2 – 3 M = ---------------------------- × 100% for R1-2 > R2-3 R1 – 2 4) Corresponding to measuring circuit in Fig. 2 5) Corresponding to measuring circuit in Fig. 2 and arrangement as shown in Fig. 1 Data Sheet 2 2000-07-01 FP 212 D 250-22 1. Digital Revolution Counting For digital revolution counting, the sensor should be actuated by a magnetically soft iron toothed wheel. The tooth spacing should correspond to about twice the magneto resistor intercenter spacing i.e. 2× 1.6 mm (see Figure 1). The two resistors of the sensor are supplemented by two additional resistors in order to obtain the sensor output voltage as a bridge voltage VOUT. The output voltage VOUT without excitation then is 0 V when the offset is compensated. Figure 1 Schematic Representation of a Toothed Wheel actuating an FP 212 D 250-22 Figure 2 Measuring Circuit and Output Voltage VOUT Waveform Data Sheet 3 2000-07-01 FP 212 D 250-22 2. Linear Distance Measurement To convert small distances into a proportional electric signal, a small soft iron part of definite width (e.g. b = 1.8 mm) is moved over the face of the sensor. Proportional signals for distances up to 1.5 mm can be obtained in this way. The sinusoidal output signal gives a voltage proportional to distance in the zero crossover region (see Figure 3). Figure 3 Arrangement for Analogue Application Maximum supply voltage versus temperature VIN = f(TA) Data Sheet 4 2000-07-01 FP 212 D 250-22 Output voltage (typical) versus temperature VOUTpp = f(TA), δ = 0.2 mm VOUTpp at TA = 25 °C ^= 100% Output voltage (typical) versus airgap VOUTpp = f(δ), TA = 25 °C VOUTpp at δ = 0.2 mm ^= 100% Total resistance (typical) versus temperature R1-3 = f(TA), δ = ∞ Max. power dissipation versus temperature Ptot = f(TA), δ = ∞ Data Sheet 5 2000-07-01