SS1881
Hall Latch - High Sensitivity
Detailed General Description
The SS1881 exhibits latch magnetic switching characteristics. Therefore, it requires both south and north poles to operate properly.
The OUT pin of these devices switches low (turns on) when a magnetic field perpendicular to the Hall sensor exceeds the operate point
threshold, BOP. After turn-on, the output voltage is VDSon. Note that the device latches, that is, a south pole of sufficient strength
towards the branded surface of the device turns the device on. The device remains on if the south pole is removed (B→0). This
latching property defines the device as a magnetic memory.
When the magnetic field is reduced below the release point, B , the OUT pin turns off (goes high). The difference in the magnetic
RP
operate and release points is the hysteresis, BHYS , of the device. This built-in hysteresis prevents output oscillation near the switching
point, and allows clean switching of the output even in the presence of external mechanical vibration and electrical noise.
The device behaves as a latch with symmetric operating and release switching points (B =|B |). This means magnetic fields with
OP RP
equivalent strength and opposite direction drive the output high and low.
Powering-on the device in the hysteresis region (less than BOP and higher than BRP) allows an indeterminate output state. The correct
state is attained after the fi rst excursion beyond BOP or BRP
.
The SOT-23 device is reversed from the UA package. The SOT-23 output transistor will be latched on in the presence of a sufficiently
strong North pole magnetic field applied to the marked face.
Output level
Output level
OUT = High
OUT = High
BHYS
BHYS
OUT = Low
OUT = Low
BRP
-30Gs typ
BOP
30Gs typ
BRP
-30Gs typ
BOP
30Gs typ
0mT
0mT
Flux density
Flux density
UA package - Latch characteristic
SE package - Latch characteristic
Unique Features
Based on mixed signal CMOS technology, SS1881 is a Hall-effect device with high magnetic sensitivity. This multi-purpose latch
meets most of the application requirements.
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 2.5V to 24V, 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 applications.
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V2.00 May.1, 2012
SECELECTRONICS [ SEC Electronics Inc. ]
