”Industry's First” Dual, 2-wire Hall-Effect Sensor Interface Solution Improves Reliability and Saves Cost in Automotive Applications

Maxim Integrated Products has introduced the MAX9921 dual, 2-wire Hall-effect sensor interface IC. This single-chip solution supplies and monitors the current drawn by two Hall-effect sensors, filters the sensed-current level, and outputs the corresponding logic level. The MAX9921 reduces interconnect cost by allowing the Hall-effect sensor to be grounded locally, which eliminates the need for an additional wire. To further reduce solution cost and save space, it replaces multiple discrete components and enhances performance with features such as input diagnostics and fault protection. The MAX9921 is ideal for myriad automotive applications, including window lifters (antipinch control), magnetic relays, automatic doors, seatbelt buckles, electric sunroofs, and powered-lift-gate controllers.

To improve reliability in automotive applications, the MAX9921 includes Hall-effect input diagnostics that detect when an input is open, shorted to the battery, or shorted to ground. If it detects any of these fault conditions, the device shuts off the current to the corresponding input. The MAX9921 provides additional circuit protection by shutting off the current to the Hall-effect sensors when the battery is out of range. Specifically designed for harsh automotive operating conditions, the MAX9921 is capable of enduring substantial ground shift and still signaling correctly. It is also robust enough to withstand up to 28V reverse voltage when the supply is within range or at ground.

The MAX9921 is available in a 10-pin microMAX(R) package that is fully specified over the -40 degrees Celsius to +125 degrees Celsius automotive temperature range. Prices start at $1.49 (1000-up, FOB USA).

Maxim Integrated Products