170°C junction Hall switch for under-hood position sensing
The TLE49641MXTMA1 is a Hall-effect magnetic switch IC from Infineon's automotive TLE49xx series, qualified to AEC-Q100. Its junction temperature range extends from -40°C to 170°C — that 170°C ceiling is the key spec for engine-bay or exhaust-adjacent mounting, where standard 150°C parts would derate or fail. The SOT23-3 package keeps the footprint small — three pins: supply, ground, open-drain output. No external pull-up is needed on the output if the downstream logic provides one; the switch sinks current when the magnetic field exceeds the operate point.
AEC-Q100 grade and active production status
Infineon lists the TLE49641MXTMA1 as Active. The AEC-Q100 qualification covers the full automotive stress suite: high-temperature operating life, temperature cycling, ESD, and latch-up. The part ships in Tape & Reel (TR) or Cut Tape (CT) options. Cut Tape suits prototype or low-volume builds. Sourced per RFQ — no stock-holding claim.
SOT23-3 footprint and thermal layout note
The SOT23-3 package has no exposed thermal pad — the junction-to-ambient thermal path runs through the leads and the PCB copper. For the 170°C TJ rating to hold in a hot environment, the board layout should connect the ground pin (pin 2) to a solid copper plane to pull heat away from the die. The open-drain output is rated for supply voltages typical of automotive 3.3 V or 5 V logic rails. No series resistor is required on the output; the pull-up resistor value sets the rise time and the current when the output is low.