The A3046EU/LU, A3056EU/LU, and A3058EU/LU Hall effect gear-tooth sensors are monolithic integrated circuits that switch in response to differential magnetic fields created by ferrous targets. These devices are ideal for use in gear-tooth-based speed, position, and timing applications and operate down to zero rpm over a wide range of air gaps and temperatures. When combined with a backbiasing magnet and proper assembly techniques, devices can be configured to give 50% duty cycle or to switch on either leading, trailing, or both edges of a passing gear tooth or slot. The six devices differ only in their magnetic switching values and operating temperature ranges. The low hysteresis of the A3046/56EU and A3046/56LU makes them perfectly suited for ABS (anti-lock brake system) or speed sensing applications where maintaining large air gaps is important. The A3046EU/LU features improved switch point stability with temperature over the A3056EU/LU. The high hysteresis of the A3058EU and A3058LU, with their excellent temperature stability, makes them especially suited to ignition timing applications where switch-point accuracy (and latching requirements) is extremely important.