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ATS673LSE-DS

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

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

Self-Calibrating TPOS Gear Tooth Sensor Optimized for Automotive Cam Sensing Applications

ATS673 and ATS674

TPOS (True Power-On State) Operation

Under specified operating conditions, the devices are guaran-

teed to attain a specified output voltage polarity at power-on, in

relation to the target feature nearest the device at that time. Both

devices offer the options of either high or low polarity over ini-

tial tooth or valley. This polarity also applies throughout device

operation.

Start-Up Detection

These devices provide an output polarity transition at the first

mechanical edge after power-on.

Undervoltage Lockout

When the supply voltage falls below the undervoltage lockout

remains in that state until the voltage level is restored to to the

have no effect until voltage is restored. This prevents false sig-

nals caused by undervoltage conditions from propagating to the

output of the sensor.

Power Supply Protection

The ATS673 and ATS674 contain an on-chip regulator and can

operate over a wide range of supply voltage levels. For applica-

tions using an unregulated power supply, transient protection

must be added externally. For applications using a regulated

supply line, EMI and RFI protection may still be required. The

circuit shown in figure 5 is the basic configuration required for

proper device operation. Contact Allegro field applications engi-

neering for information on the circuitry required for compliance

to various EMC specifications.

Internal Electronics

These devices contain a self-calibrating Hall effect IC that

provides a Hall element, a temperature compensated ampli-

fier, and offset cancellation circuitry. The IC also contains a

voltage regulator that provides supply noise rejection over the

operating voltage range. The Hall transducers and the electron-

ics are integrated on the same silicon substrate by a proprietary

BiCMOS process. Changes in temperature do not greatly affect

this device due to the stable amplifier design and the offset rejec-

tion circuitry.

4

VCC

Sensor Output

GND

VOUT

TEST

0.1 µF

ATS673/674

1

2

3

Figure 5. Power Supply Protection Typical Circuit