The A1250 Hall-effect sensor IC is a stable, stress-resistant bipolar switch at a wide range of temperatures. It is the most sensitive Hall-effect device in Allegro's® bipolar switch family and features ring magnet sensing. Allegro's patented dynamic offset cancellation technology takes advantage of the stable chopper characteristics to ensure the product's superior high temperature resistance. This method reduces the residual offset voltage typically caused by device overmolding, temperature dependence, and thermal stress.
The A1250 includes the following components on a single silicon: voltage regulator, Hall generator, small signal amplifier, stabilized chopport, Schmidt flip-flop, and open-drain output with short-circuit protection. The advanced BiCMOS wafer processing process takes advantage of low voltage requirements, component matching, very low input offset errors, and small component geometries.
The A1250 Hall-effect bipolar switch opens when the magnetic field strength of the south pole is sufficient and closes when the magnetic field strength of the north pole is sufficient. Because there is no definition of the output state of whether the magnetic field is reduced or removed, Allegro recommends that you use bipolar magnets and set sufficient magnetic field in your application to ensure that the device is open.
The A1250 is rated for operating ambient temperatures of L, –40°C to 150°C. Both packages provide a magnetically optimized solution for most applications. All packages are lead-free, and the pin frames are 100% matte tin plated.