Features

• A1225/7/9 High Temperature Hall Effect Latches, Allegro Microsystems. The A1225/7/9 High Temperature Hall Effect Latches are temperature-stable and stress resistant suitable for operation for temperatures up to 150°C. A Schmitt trigger circuit maintains operate and release point symmetry by compensating for temperature changes in the Hall element. Internal compensation provides magnetic switchpoints 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 three basic devices (A1225, A1227, and A1229) are identical except for magnetic switchpoints. They also include a voltage regulator, Hall-voltage generator, temperature compensation circuit, signal amplifier, and a buffered open-drain output to sink up to 25 mA. The on-board regulator permits operation with supply voltages of 3.8 V to 24 V. The first character of the part number suffix determines the device operating temperature range. Suffix L is for –40°C to 150°C. Two package styles provide a magnetically optimised package for most applications. Available in a SOT89/TO-243AA package for surface-mount applications or three-lead ultra-mini-SIP. Symmetrical switchpoints Superior temperature stability Operation from unregulated supply Open-drain 25 mA output Reverse battery protection Activate with small, commercially available permanent magnets Resistant to physical stress Enhanced ESD structures result in 8 kV HBM ESD performance Internal protection circuits enable 40 V load dump compliance