These Hall-effect latches are extremely temperature-stable and stress resistant sensors especially suited for operation over extended temperature ranges to +150°C. Superior high-temperature performance is made possible through a novel Schmitt trigger circuit that maintains operate and release point symmetry by compensating for temperature changes in the Hall element. Additionally, internal compensation provides magnetic switch points that become more sensitive with temperature, hence offsetting the usual degradation of the magnetic field with temperature. The symmetry capability makes these devices ideal for use in pulse-counting applications where duty cycle is an important parameter. The four basic devices (3185, 3187, 3188, and 3189) are identical except for magnetic switch points.

Each device includes on a single silicon chip a voltage regulator, quadratic Hall-voltage generator, temperature compensation circuit, signal amplifier, Schmitt trigger, and a buffered open-collector output to sink up to 25 mA. The on-board regulator permits operation with supply voltages of 3.8 to 24 volts.

The first character of the part number suffix determines the device operating temperature range. Suffix ‘E–’ is for -40°C to +85°C, and suffix ‘L–’ is for -40°C to +150°C. Three package styles provide a magnetically optimized package for most applications. Suffix ‘–LT’ is a miniature SOT89/TO-243AA transistor package for surface-mount applications; suffix ‘–UA’ is a three-lead ultra-mini-SIP.

FEATURES

■ Symmetrical Switch Points

■ Superior Temperature Stability

■ Operation From Unregulated Supply

■ Open-Collector 25 mA Output

■ Reverse Battery Protection

■ Activate With Small, Commercially Available Permanent Magnets

■ Solid-State Reliability

■ Small Size

■ Resistant to Physical Stress

A3281LLT属于传感器，变送器 > 磁性传感器 - 开关（固态）。Allegro MicroSystems制造生产的A3281LLT磁性传感器 - 开关（固态）该系列产品使用固态技术来检测是否存在超过某个特定幅度和/或标示的磁场，并提供指示是否存在此类磁场的双态输出。它们与磁簧开关以及线性或罗盘型固态器件不同，前者通过使用移动机械部件来提供类似的功能，后者提供指示所施加磁场的强度和/或方向的可变输出。