US4881

Bipolar Hall Switch

Low Voltage & Very High Sensitivity

3901004881

Page 5 of 11

Data Sheet

Rev 011

Feb/06

9 Detailed General Description

Based on mixed signal CMOS technology, Melexis US4881 is a Hall-effect device with very high magnetic

sensitivity. It allows using generic magnets, weak magnets or larger air gap.

The chopper-stabilized amplifier uses switched capacitor techniques to suppress the offset generally

observed with Hall sensors and amplifiers. The CMOS technology makes this advanced technique possible

and contributes to smaller chip size and lower current consumption than bipolar technology. The small chip

size is also an important factor to minimize the effect of physical stress.

This combination results in more stable magnetic characteristics and enables faster and more precise design.

The operating voltage from 2.2V to 18V, low current consumption and large choice of operating temperature

range according to “L”, “K” and “E” specification make this device suitable for automotive, industrial and

consumer low voltage applications.

The output signal is open-drain type. Such output allows simple connectivity with TTL or CMOS logic by using

a pull-up resistor tied between a pull-up voltage and the device output.

10 Unique Features

The US4881 exhibits bipolar magnetic switching characteristics. Therefore, it operates with both south and

north poles.

Latch characteristic

Typically, the device behaves as a latch with symmetric

magnetic fields with equivalent strength and opposite direction

drive the output high and low.

Removing the magnetic field (B→0) keeps the output in its

previous state. This latching property defines the device as a

magnetic memory.

and low by only using one magnetic pole. In such case, removing the magnetic field changes the output level.

Unipolar positive switch characteristic

Unipolar negative switch characteristic

a minimal value. This hysteresis prevents output oscillation near the switching point.