ATS660LSB

TRUE ZERO-SPEED,

HALL-EFFECT ADAPTIVE

GEAR-TOOTH SENSOR

www.allegromicro.com

9

DEVICE DESCRIPTION — Continued

Power-on state operation. The device is guaranteed

to power on (power up) in the off state (high output

voltage) regardless of the presence or absence of a gear

tooth.

Under-voltage lockout. If the supply voltage falls

below the minimum operating voltage (V

device output will turn off (high output voltage) and stay

off irrespective of the state of the magnetic field. This

prevents false signals caused by under-voltage conditions

from propagating through to the output of the sensor.

Output. The output of the sensor is a short-circuit-

protected open-collector stage capable of sinking 20 mA.

An external pull-up (resistor) to a supply voltage of not

more than 26.5 V must be supplied.

Dwg. AH-006-1

1

2

3

4

APPLICATIONS INFORMATION

Dwg. AH-007

1

2

3

4

Output polarity. The output of the device will switch

from off to on as the leading edge of the target passes the

sensor in the direction indicated (pin 4 to pin 1), which

means that the output voltage will be low when the unit is

facing a tooth. If rotation is in the opposite direction (pin

1 to pin 4), the output of the device will switch from on to

off as the leading edge of the target passes the sensor,

which means that the output voltage will be high when the

unit is facing a tooth.

Power supply protection. The device contains an on-

chip regulator and can operate over a wide supply voltage

range. For devices that need to operate from an unregu-

lated power supply, transient protection should be added

externally. For applications using a regulated line, EMI/

RFI protection is still required. Incorrect protection can

result in unexplained pulses on the output line, providing

inaccurate sensing information to the user.

EMI protection circuitry can easily be added to a PC board

for use with this device. Provisions have been made for

easy mounting of this board on the back of the unit. PC

board installation parallel to the device axis is also pos-

sible.