The MAX9921 provides a single chip solution to interface
two 2-wire Hall-effect sensors to a low-voltage micro-
processor (μP). This device supplies and monitors the cur-
rent drawn by two Hall-effect sensors, filters the sensed
current level, and outputs the corresponding logic level.
The MAX9921 includes input diagnostics and fault pro-
tection. These features allow the device to determine fault
conditions such as open inputs, inputs shorted to the bat-
tery, and inputs shorted to ground. If the MAX9921
detects any of these conditions at either IN1 or IN2, the
device shuts off the current to the corresponding input.
The MAX9921 protects the Hall sensors from supply tran-
sients up to 60V at the BAT supply. Normal operating
supply voltage ranges from 6V to 18V. If the battery volt-
age is out of range, the MAX9921 shuts off the current to
the Hall sensors.
The MAX9921 provides an 80μs blanking time following
Hall sensor power-up or restart. The open-drain logic
outputs are compatible with logic levels up to 5.5V.
The MAX9921 is available in a small 10-pin μMAX?
package and is specified over the -40°C to +125°C
automotive temperature range.
Applications
Door Modules
Window Lifters
Seat Movers
Electric Sunroofs
Powered Lift Gate
Controllers
Powered Running Boards
Seatbelt Buckles