115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

ATS622LSB

TRUE ZERO-SPEED,

GEAR-TOOTH SENSOR

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DEVICE DESCRIPTION — Continued

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APPLICATIONS INFORMATION

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. Note that the circuit is ready to accurately detect the

first gear edge that results in a tooth-to-valley transition

after the circuit has successfully powered on.

Under-voltage lockout. If the supply voltage falls

below the under-voltage lockout (V

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

irrespective of the state of the magnetic field. This pre-

vents false signals caused by under-voltage conditions

from propagating through to the output of the sensor.

Output. The output of the module 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 24 V must be supplied.

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 current 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 low 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

possible.