Inductive Position Sensors

Microsemi’s sensor interface ICs provide the ideal interface between high-reliability and safety-critical automotive position sensor applications. Our unique magnetic field sensors provide accurate position measurements, are immune to stray magnetic fields, and don’t require an external magnetic device. 



Microsemi has been shipping magnetic field sensors since 2010, and has released the LX3301A and LX3302A to meet your highperformance position requirements. 

Microsemi’s magnetic field interface ICs are an exciting technology, and have significant advantages over existing Hall effect and other magnetic sensors.



The LX3301A and LX3302A improve angular measurement accuracy, lower noise sensitivity, and reduce system costs. These inductive sensors use a primary coil to generate an AC magnetic filed; the magnetic field then couples onto two secondary coils to generate voltages.  The metal target disturbs the magnetic field generated by the primary coil, hence, the voltages received by the secondary coils would vary based on different metal target positions, we then use the unique ratio of the secondary coil voltages to determine the position of the metal target.  By using the inductive position sensor approach, it allows us to make the biggest improvement in high-temperature and safety-critical applications such as automobile throttle body, transmission gear sensing, electronic power steering, and accelerator pedals, with no magnet needed.



How the Inductive Sensor Works

1.  No magnet needed.  Instead, a primary coil is used to generate an AC magnetic field.
2. The magnetic field couples onto two secondary coils generating a voltage.
3. A metal target disturbs the generated magnetic field.
4. The secondary coils receive different voltages vs. target position.
5. Position is determined by the ratio of secondary coil voltages.

                                
                                             Sensor PCB Example: 10 x 24mm Linear  

    
                              Sensor PCB Example: 20mm Rotary


We currently have two available products in the inductive position sensor family, LX3301A is good for applications with up to 125°C temperature and Analog/PWM output options, while LX3302A is available for higher temperature requirements and additional output interfaces such as SENT and PSI5.  Detailed spec comparison of the two parts are listed below.