SS1438
Unipolar Hall Switch
Output Behavior versus Magnetic Pole
DC Operating Parameters TA = -40°C to 150°C, VDD = 2.5 to 24V (unless otherwise specified)
Test Conditions (UA) Test Conditions (SO)
OUT
High
Low
B > BRP
B < BOP
B < BRP
B > BOP
The SOT-23 device is reversed from the UA package. The SOT-23 output transistor will be turned on(drops low) in the presence of a
sufficiently strong South pole magnetic field applied to the marked face.
Application Information
It is strongly recommended that an external bypass capacitor be connected (in close proximity to the Hall sensor)
between the supply(VDD Pin) and ground(GND Pin) of the device to reduce both external noise and noise gener-
ated by the chopper stabilization technique. As is shown in the following figure, a 0.1μF capacitor is typical.
For reverse voltage protection, it is recommended to connect a resistor or a diode in series with the VDD pin.
When using a resistor, three points are important:
- the resistor has to limit the reverse current to 50mA maximum (VCC / R1 ≤ 50mA)
- the resulting device supply voltage VDD has to be higher than VDD min (VDD = VCC – R1*IDD
- the resistor has to withstand the power dissipated in reverse voltage condition (P = VCC
)
2/R1)
D
When using a diode, a reverse current cannot flow and the voltage drop is almost constant (≈0.7V).
Therefore, a 100Ω/0.25W resistor for 5V application and a diode for higher supply voltage are recommended.
Typical Three-Wire Application Circuit
When a weak power supply is used or when the device is intended to be used in noisy environment, it is
recommended that following figure is used.
5
V3.10 Nov 1, 2013
SECELECTRONICS [ SEC Electronics Inc. ]
