US5881
Unipolar Hall Switch – Low Sensitivity
9 Detailed General Description
Based on mixed signal CMOS technology, Melexis US5881 is a Hall-effect device with low magnetic
sensitivity. Its sensitivity enables high accuracy in position sensing by the use of small air gap.
The chopper-stabilized amplifier uses switched capacitor technique 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 wide operating voltage from 3.5V to 24V, “L” and “E” operating temperature range and low current
consumption make this device especially suitable for automotive solid state switch 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 US5881 exhibits unipolar magnetic switching characteristics. Therefore, it operates only with one
magnetic pole.
The UA package is south pole active:
Applying a south magnetic pole greater than B
OP
facing the
branded side of the package switches the output low.
The SE package is north pole active:
Applying a north magnetic pole greater than B
OP
facing the
branded side of the package switches the output low.
Removing the magnetic field (B→0) switches the output high.
The use of the opposite magnetic pole facing the branded side
does not affect the output state.
Unipolar switch characteristic
A magnetic hysteresis B
HYST
keeps B
OP
and B
RP
separated by a minimal value. This hysteresis prevents
output oscillation near the switching point.
3901005881
Rev 007
Page 5 of 11
Data Sheet
Feb/06
MELEXIS [ Melexis Microelectronic Systems ]
