MLX90248ESE-EBA-000-RE, Melexis Surface Mount Hall Effect Sensor, TSOT, 3-Pin, Датчик Холла

The MLX90248 is most commonly found in mobile phone applications for detecting the open/close action of the lid (flip, slide and swivel type phones) and also to detect the (un)holstered condition of brick and smartphones. The goal of this detection is to switch on or off the power hungry displays, backlights and keypad illumination whenever the lid is opened or closed. Thereby maximizing battery life between charges.
The same operation principle can be simply applied to many other battery-powered devices like laptops, digital cameras and camcorders, music players and handheld gaming devices.
This very high sensitivity Hall sensor IC allows the use of only a very small and cheap magnet to trigger the MLX90248, hence it can easily replace a reed switch.
Several benefits derive from using a Hall sensor IC. One is to provide solid state switching, which is bounce-free, more reliable and with increased lifetime compared to usual mechanical contacts. The other is seamless pick and place manufacturing as the device is available in standard, lead-free and green surface mount technology.

Datasheet