SS1881

Hall Latch - High Sensitivity

6

V2.00

May.1, 2012

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 generated by the chopper stabilization

technique. As is shown in the two figures in next page, 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)

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 recommended that

figure 13.3 from the Application Information section is used.

The low-pass filter formed by R1 and C1 and the zener diode Z1 bypass the disturbances or voltage spikes occurring on the device

supply voltage VDD. The diode D1 provides additional reverse voltage protection.

S1881

R2

C2

VDD

GND

OUT

C1

S1881

R1:100

VDD

GND

OUT

C1

Z1

D1

Automotive and Severe

Environment Protection Circuit

Typical Three-Wire Application Circuit

C2

R2

The SS1881 have been optimized for commutation applications in 5V and 12V brushless DC motors. The follow figure is the typical

application circuit for 3 phase brushless DC motors.