A3250 Datasheet | Allegro MicroSystems

Features and Benefits - Chopper stabilization for stable switchpoints throughout operating temperature range - Externally programmable operate point (through VCC pin) - On-board voltage regulator for 4.2 V to 24 V operation - On-chip protection against: ▫ Supply transients ▫ Output short-circuits ▫ Reverse-battery condition Description The A3250 and A3251 are field-programmable, chopperstabilized, unipolar Hall-effect switches designed for use in high-temperature applications. These devices use a chopper-stabilization technique to eliminate offset inherent in single-element devices. The A3250 and A3251 are externally programmable devices. The devices have a wide range of programmability of the magnetic operate point (BOP) while the hysteresis remains fixed. This advanced feature allows for optimization of the sensor switchpoint and can drastically reduce the effects of variations found in a production environment, such as magnet and device placement tolerances. These devices provide on-chip transient protection. A Zener clamp on the power supply protects against overvoltage conditions on the supply line. These devices also include short-circuit protection on the output. The output of the A3250 switches LOW when subjected to a south-polarity magnetic field with a flux density that exceeds the threshold for BOP , and switches HIGH when the Package: 3 pin SOT89 (suffix LT) and 3 pin SIP (suffix UA) .. Continued on the next page… Not to scale Functional Block Diagram Program/Lock Programming Logic Regulator Offset Adjust Sample and Hold Dynamic Offset Cancellation VOUT Amp Current Limit Low-Pass Filter 3250-DS Rev. 3 A3250 and A3251 Field-Programmable, Chopper-Stabilized, Unipolar Hall-Effect Switches Three package styles provide a magnetically optimized package for most applications. Type LT is a miniature SOT89/TO-243AA surface mount package that is thermally enhanced with an exposed ground tab, and type UA is a three-lead ultramini SIP for...