Position sensors play an increasingly important role in many industrial, robotic and medical applications. Advanced applications in harsh environments need sensors that perform well, even when exposed to oil, dirt and dust. The TE Connectivity (TE) KMXP position sensor is the right choice to meet those needs thanks to its Magnetoresistive technology and available form factors. The KMXP sensor provides greater precision than commonly used Hall sensors and is designed to provide reliable and accurate measurements in harsh environments including high temperatures. The sensor measuring principle is based on the anisotropic magnetoresistance effect (AMR effect). The sensors are offered in two different DFN packages for multiple orientation options. These packages can be easily integrated to almost any automated assembly process.
Position sensors based on the magneto resistance effect combine high precision with cost effectiveness for linear displacement measurements. The contactless measurement principle offers clear advantages versus optical encoder systems in harsh environments. Coming from applications with medium accuracy demands but high mechanical tolerances, the whole spectrum of displacement tasks down to nanoscale measurements can be solved with scale based magneto resistive sensor systems. Embedded in a small, modern DFN package for standard, flat or perpendicular mounting, the linear magneto resistive sensors can now easily be applied to a wide range of applications with small design space using standard SMT assembly processes.
Learn about magnetoresistive sensor technology, the features and benefits of the KMXP series, and the various applications and industries in which the sensor can be used.
Contactless linear or angular position measurement in applications like:
Q: What accuracy can be achieved with the KMXP AMR position sensor?
A: The accuracy depends on several factors, see KMXP White Paper. With standard scales, precision values of <1% of the pole pitch are common, e.g. <10µm accuracy for 1mm pole pitch.
Q: What interfaces are supported?
A: The sensor output are two differential sin/cos analog signals with a typical signal output range of 100mVpp at Vcc=5V. We recommend to amplify the signals.
Q: Are there any standard components that read out and calculate the position?
A: There are several standard ASIC suppliers in the market; please contact us for more.
Q: What scale / pole wheel can be used together?
A: Standard scale / pole wheels are available on the market.
Q: Are there different scale qualities available?
A: Yes, the accuracy of a magnetic scale is given in µm/m. Different classes of accuracy exist, e.g.: A40 = ±40um/m ; A20 = ±20um/m.
Q: Are there any restriction regarding scale width?
A: The available scales widths are typically in the range of 2mm … 20mm. Common scale widths are 6mm or 10mm. Small scale widths require accurate magnetic design.
Q: What is the optimum air gap?
A: The optimimum air gap depends mainly on the magnetic scale material and the pole pitch. Rule of thumb for ferrite based scales is: max. air gap = 0.5 x pole pitch, e.g: KMXP5000 à max. 2.5mm gap.
Q: Do I need a (non magnetic) steel backing on my magnetic scale?
A: Yes, it ensures accuracy of the scale.
Q: How is the sensor oriented relative to the scale?
A: The KMXP sensors measure perpendicularly to the scale (90° angle between sensor and scale). The KMXP AMR sensor comes in two different package variants that allow either perpendicular (KMXPx000) or parallel (KMXPx002) orientation with respect to the PCB.
Q: How accurate must the sensor be aligned with respect to the scale?
A: The KMXP AMR sensor must be aligned at ±3° with respect to the scale; more precise arrangement increases accuracy.
Q: Is there a perpendicular version?
Yes, KMXPx002 series is the perpendicular version, where the PCBA is parallel to scale.
Q: Can I use the KMXP senor to measure along the circumference of a circular set up?
A: Yes, the KMXP is very well suited for measurements along the circumference. As it measures the field distribution, it is not sensitive to excentric errors.
Q: What is the smallest diameter of the pole wheel for a circular set up?
A: The diameter depends on the accuracy of the target; for example for KMXP5000 series with d=80mm the results in accuracy are of ±40µm. For more information contact us.
Q: What pole pitches do you support?
A: There are three different pole pitches of 5mm, 2mm and 1mm.
Q: How fast is the KMXP AMR sensor? How fast can I measure with a pole wheel?
A: The update rate of the KMXP is in MHz region as the analog signal response is nearly instantaneous.
Q: Does the KMXP need to be calibrated?
A: While the sensor does not require calibration, for higher accuracy demands, a calibration of the signal processing unit should be considered.
Q: Can the KMXP function with another supply voltage than 5V? Like 1V or 10V?
Yes, the supply voltage range extends from >0V to 10V. For Wheatstone bridges, the output signal amplitude is direct proportional to the supply voltage.
Q: Is there a standard analog read out circuit avilable? Where can I find it?
Yes, there's a standard analog circuit; please refer to the KMXP datasheet.
Q: How sensitive is the KMXP to external disturbing magnetic fields?
A: Thanks to the gradient field design, the KMXP sensors are not sensitive to homogeneous fields up to approximately 4 kA/m.
Q: How sensitive is the KMXP to EMC?
The KMXP follows the "Human Body Model" conformity up to 1.5kV (class 1C), making the sensor insensitive to disturbing electromagnetic (EMC) fields.
Q: Is there a digital AMR position sensor version?
The digital output version is under development. Contact us to remain informed on its release.
Q: How to process the biggest pad at the bottom of the sensor package? (connect to GND or NC).
A: This is a heat sink and we propose not to solder this pad.
Q: Do you have recommended footprint for KMXP series also including KMXP5000?
A: Yes, all device from the KMXP series have the same foot print. For more details see the Application Note.
Q: In the datasheet, the sensor is represented with a PCB, do you provide such board with a sensor? if yes, what is the PN?
A: This picture of a PCB with our KMXP is for illustration only. We have no PCB availabe .
Q: Where can I get samples?
View the part number table above to find products available through distribution partners.
Q: Where can I buy it?
A: There are several suppliers in the market, contact us for more.
Please review product documents or contact us for the latest agency approval information.