3150 Datasheet | Allegro MicroSystems

PROGRAMMABLE, CHOPPERSTABILIZED, HALL-EFFECT SWITCH The A3150JLT and A3150JUA programmable switches provide tooth/valley recognition in large gear-tooth sensing applications. Each sensor consists of a single element, chopper-stabilized Hall-effect IC that can be programmed to the desired magnetic switch point, optimizing sensor airgap and timing accuracy performance after final packaging. The small package can be easily assembled and used in conjunction with a wide variety of gear/target shapes and sizes. The two devices differ only in package style. The sensing technology used for this sensor is Hall-effect based. The sensor incorporates a single-element Hall IC that switches in response to magnetic signals created by a ferrous target. The programmability of the circuit eliminates magnet and system offsets such as those caused by tilt yet provides zero-speed detection capabilities without the associated running jitter inherent in classical digital solutions. A proprietary dynamic offset cancelation technique, with an internal high-frequency clock, reduces the residual offset voltage, which is normally caused by device overmolding, temperature dependancies, and thermal stress. This technique produces devices that have an extremely stable quiescent output voltage, are immune to mechanical stress, and have precise recoverability after temperature cycling. Many problems normally associated with low-level analog signals are minimized by having the Hall element and amplifier in a single chip. Output precision is obtained by internal gain adjustments during the manufacturing process and operate-point programming in the user’s application. This sensor system is ideal for use in gathering speed, position, and timing information using gear-tooth-based configurations. The A3150JLT/JUA are particularly suited to those applications that require accurate duty cycle control or accurate edge detection. The lower vibration sensitivity also makes these devices extremely...