HKZ 121 Hall-Effect Vane Switch HKZ 121 Features Bipolar IC ● ● ● ● ● ● ● ● ● Contactless switch with open collector output (40 mA) Static switching High switching frequency Hermetically sealed with plastic Unaffected by dirt, light, vibration Large temperature and voltage range Integrated overvoltage protection High interference immunity Integrated capacitors for EMI protection P-HKZ-3-1 Type Ordering Code Package HKZ 121 Q67000-A9097-A401 P-HKZ-3-1 The Hall-effect vane switch HKZ 121 is a contactless switch consisting of a monolithic integrated Hall-effect circuit and a special magnetic circuit hermetically sealed in a plastic package. The switch is actuated by a soft-iron vane which is passed through the air gap between magnet and Hall sensor. The main application field is in cars, i.e. as a breakerless trigger in electronic ignition systems. Numerous industrial applications can be found in control engineering, especially in those areas where switches must operate maintenance-free under harsh environmental conditions (e.g. rpm sensor, limit switch, position sensor, speed measurement, shaft encoder, scanning of coding disks, etc.). HKZ 121 Function The Hall-effect switch is actuated by a soft-iron vane that passes through the air gap between magnet and Hall-effect sensor. The vane short-circuits the magnetic flux before the hall-effect sensor, as shown below. The open collector output is conductive (low) when the vane is outside the air gap, and blocks (high) when the vane is introduced into the air gap. The output remains high as long as the vane remains in the air gap. This static function does not require a minimum operating frequency. The output signal shape is independent of the operating frequency. The circuit features integrated overvoltage protection against most of the voltage peaks occurring in automotive and industrial applications. The output stage has a Schmitt trigger characteristic. Most electronic circuits can be driven directly due to the open collector output current of max. 40 mA. a) Magnetic flux through the Hall-effect switch with no vane in the gap b) Magnetic flux short-circuited by the soft-iron vane Principle of Operation Mechanical Characteristics The Hall-effect vane switch is hermetically sealed in a special plastic package, so that it can also be used under harsh environmental conditions. The package is waterproof, vibrationresistant and resistant to gasoline, oil and salt. Two tubular rivets are incorporated in the package to mount the sensor on its carrier plate. The circuit has three flexible leads for power supply, output and ground. HKZ 121 Application Notes The output current of the "open collector" must be limited to the maximum permissible value by a load resistor adapted to the application. For optimum efficiency of the integrated overvoltage protection, it is suggested that a resistor of approx. 100 Ω be provided in the component's power supply to limit the current. Absolute Maximum Ratings Parameter Symbol Limit Values min. max. Unit Test Condition Supply voltage VS – 1.2 Output voltage in OFF-state VQ – 0.8 24 30 30 V V V – TA = 25 ˚C – Inverse supply current (limited externally) Output current Inverse output current – IS – 200 mA IQ – IQ – – 40 30 mA mA TA ≤ 80 ˚C t≤1 h without vane Ambient temperature Storage temperature TA Tstg – 40 – 40 135 150 ˚C ˚C – – Thermal resistance system - air Rth SA – 170 K/W – Supply voltage VS 4.5 24 V – Ambient temperature TA – 40 130 ˚C – Vane1): thickness width gap length immersion depth gap height a b c h d 0.5 8 8 4.6 7.3 – h mm mm mm mm mm – – – – – Operating Range 1) see Figure Mechanical Measurement Conditions 9 HKZ 121 Characteristics VS = 5 V to 18 V, TA = – 30 to 130 ˚C Parameter Symbol Limit Values min. max. Unit Test Condition Output saturation voltage VQ sat – – – 0.4 0.6 – – V V without vane IQ = 40 mA TA = – 30 to 110 ˚C TA = 110 to 130 ˚C Output reverse current Supply current IQ R IS – – 10 12 µA mA with vane without vane Fall time tHL – 1 µs IQ = 40 mA Overvoltage protection – Supply voltage (VS) – Output (VQ) VSZ VS0 32 32 42 42 V V IS = 16 mA IS = 16 mA Switching Point Characteristics Definitions In most applications, the switching point is set exactly by mechanical adjustment, thus compensating all mechanical tolerances in the system including the scatter of the Hall-effect vane switch. For the function of the device in operation, only the deviations of those characteristics are important on temperature and operating voltage. The characteristic values of the switching points are, therefore, not directly referred to the mechanical dimensions of the vane switch, but to an electrically defined symmetry B0 according to formula 1): 1) B0 = (ON left + OFF left + ON right + OFF right): 4 B0 = A0 ± 0.3 mm The definition of the operate and release points is shown the following figure. Operate point fON is obtained by subtracting the measured ON operate value from the reference point B0: 2) f ON = ON right – B0 = B0 – ON left The release point fOFF is calculated from the difference between the appropriate ON and OFF points: 3) f OFF = ON right – OFF right = OFF left – ON left fON 0 and fOFF 0 are the switching points measured for the individual component under normal conditions (VS = 12 V, TA = 25 ˚C) within the characteristic device deviation. The deviations of the operate and release points are defined according to 4): 4) ∆f ON = f ON – f ON 0 ∆f OFF = f OFF – f OFF 0 HKZ 121 Switching Point Definitions HKZ 121 Mechanical Measurement Conditions Switching Point Characteristics Vane: a = 0.75 mm, b = 8 mm, c = 10 mm Position: center of air gap VS = 5 V to 18 V Parameter Symbol min. Limit Values typ. max. Unit Test Condition HKZ 121 Operate point Deviations fON 0 ∆fON 0.85 – 0.4 – 0.2 – 0.4 1.45 0.15 0.15 0.2 2.05 0.7 0.4 0.7 mm mm mm mm VS = 12 V, TA = 25 ˚C TA = – 30 to 25 ˚C TA = 25 to 80 ˚C TA = 80 to 130 ˚C Release point Deviations fOFF 0 ∆fOFF 1.54 – 0.8 – 0.4 – 0.8 2.54 0.3 0.3 0.4 3.54 1.4 0.8 1.4 mm mm mm mm VS = 12 V, TA = 25 ˚C TA = – 30 to 25 ˚C TA = 25 to 80 ˚C TA = 80 to 130 ˚C HKZ 121 Package Outlines GHK05083 Special Package, P-HKZ-3-1 (Plastic Hall-Effect Vane Switch) Dimensions in mm