What this switch is and where it fits
The TLE49642MXTMA1 is a unipolar Hall-effect switch from Infineon's automotive-grade TLE496x family, qualified to AEC-Q100. It detects a south-pole magnetic field and switches an open-drain output low when the flux density exceeds 36 mT, releasing at 15.9 mT. The part is designed for position and proximity sensing in powertrain, chassis, and body electronics where the ambient temperature can hit 170°C at the junction. Because it is a unipolar switch, it responds only to one magnetic polarity — south pole. That means the magnet must be oriented correctly in the assembly; a north-pole field will not trigger it. This is not a latching or bipolar device, so the output returns high when the field drops below the release point.
Magnetic thresholds and what they mean for the air gap
The 36 mT operate point and 15.9 mT release point define the hysteresis band, which prevents chatter at the switching threshold. The open-drain output sinks up to 25 mA and requires an external pull-up resistor to the supply rail. The 3 V supply is the nominal operating voltage.