SS579
Hall Latch - High Sensitivity
state. The correct state is attained after the first 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 pres-
ence of a sufficiently strong North 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 two figures, a 0.1μF capacitor is typical.
Typical Three-Wire Application Circuit
VDD
R2
C2
C1
OUT
SS579
GND
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 (PD = VCC2/R1)
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. Both
solutions provide the required reverse voltage protection.
When a weak power supply is used or when the device is intended to be used in noisy environment, it is recom-
mended the following figure is used.
The low-pass filter formed by R1 and C1 and the Zener diode Z1 bypass the disturbances or voltage spikes occur-
ring on the device supply voltage VDD. The diode D1 provides additional reverse voltage protection.
Automotive and Severe Environment Protection Circuit
R1:100
VDD
R2
C2
C1
D1
Z1
OUT
SS579
GND
The SS579 have been optimized for commutation applications in 5V and 12V brushless DC motors. The following
figure in the next page is the typical application circuit for 3 phase brushless DC motors.
5
V3.10 Nov 1, 2013
SECELECTRONICS [ SEC Electronics Inc. ]
