Hall-Effect Latches and Bipolar Switches

Hall-effect latches are most commonly used in sensing multi-pole ring magnets for motor commutation, because they require a south pole of sufficient strength to turn the output on and a north pole of sufficient strength to turn the output off. These contactless sensing solutions require few external components and can withstand the hostile operating conditions of automotive applications.

Specific advantages of Allegro’s solutions include:

• 4× chopper-stabilization for offset cancellation provides: enhanced switch point stability that increases accuracy in measuring motor speed or duty cycle, and industry leading jitter performance that is 2× better than competitor devices
• Low voltage (3 V) operation and lower ICC for more power efficient devices
• Certain products (A1225, A1227, A1229) are designed to survive harsh automotive transient conditions, including double battery and 40 V load dump, without a limiting series resistor, eliminating the need for external components and preventing transient voltage field failures

Allegro is a market leader in the area of Hall latches, and has a broad range of part sensitivities for latches that cover any desired magnetic switch points for just about any application requirement.