ATS642LSHTN-I1-T Allegro Microsystems Inc, ATS642LSHTN-I1-T Datasheet - Page 10

• Manufacturer Part Number: ATS642LSHTN-I1-T
• Description: IC SENSOR GEAR TOOTH 4-SIP
• Manufacturer: Allegro Microsystems Inc
• Type: Special Purposer

Specifications of ATS642LSHTN-I1-T

• Output Type: Digital, Open Collector
• Sensing Range: 120mV Trip, 120mV Release
• Voltage - Supply: 4 V ~ 24 V
• Current - Supply: 8mA
• Features: Gear Tooth Type
• Operating Temperature: -40°C ~ 150°C
• Package / Case: 4-SIP
• Termination Type: Through Hole
• Bandwidth: 40kHz
• Supply Voltage Max: 24V
• Leaded Process Compatible: Yes
• No. Of Pins: 4
• Mounting Type: Through Hole
• Hall Effect Type: Gear Tooth
• Supply Voltage Min: 4V
• Filter Terminals: Through Hole
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output (max): -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

ATS642LSH
Figure 1. Relative motion of the target is detected by the dual Hall ele-
ments mounted on the Hall IC.
Figure 2. This left-to-right (pin 1 to pin 4) direction of target rotation
results in a low output signal when a tooth of the target gear is nearest
the face of the sensor (see figure 3). A right-to-left (pin 4 to pin 1) rota-
tion inverts the output signal polarity.
Sensing Technology
The gear tooth sensor subassembly contains a single-chip dif-
ferential Hall effect sensor IC, an optimized samarium cobalt
magnet, and a flat ferrous pole piece. The Hall IC possesses two
Hall elements, which sense the magnetic profile of the ferrous
target simultaneously, but at different points (spaced at a 1.5 mm
pitch), generating a differential internal analog voltage (V
that is processed for precise switching of the digital output
signal.
The Hall IC is self-calibrating and also possesses a temperature
compensated amplifier and offset compensation circuitry. Its
voltage regulator provides supply noise rejection throughout the
operating voltage range. Changes in temperature do not greatly
affect this device due to the stable amplifier design and the offset
compensation circuitry. The Hall transducers and signal process-
ing electronics are integrated on the same silicon substrate, using
a proprietary BiCMOS process.
Target Profiling
An operating device is capable of providing digital information
that is representative of the mechanical features on a rotating
target. The waveform diagram shown in figure 3 presents the
automatic translation of the mechanical profile, through the
magnetic profile that it induces, to the digital output signal of the
sensor.
Hall Effect Device
Hall Element 2
Dual-Element
Target (Gear)
Rotating Target
(Pin 4 Side)
South Pole
North Pole
Peak-Detecting Gear Tooth Sensor with Continuous Calibration
1
4
(Pin 1 Side)
(Concentrator)
Element Pitch
Hall Element 1
Hall IC
Pole Piece
Back-biasing Magnet
Case
Branded Face
of Sensor
Functional Description
Two-Wire True Zero Speed Miniature Differential
PROC
)
Output Polarity
Figure 3 shows the output polarity for the orientation of target
and sensor shown in figure 2. The target direction of rota-
tion shown is: perpendicular to the leads, across the face of the
device, from the pin 1 side to the pin 4 side. This results in the
sensor output switching from high, I
the leading edge of a tooth (a rising mechanical edge, as detected
by the sensor) passes the sensor face. In this configuration, the
device output current switches to its low polarity when a tooth is
the target feature nearest to the sensor. If the direction of rota-
tion is reversed, then the output polarity inverts.
Note that output voltage polarity is dependent on the position of
the sense resistor, R
Figure 3. Output Profile of a ferrous target for the polarity indicated in
figure 2.
Figure 4: Voltages profiles for high side and low side two-wire sensing.
Target
Mechanical Profile
Representative
Differential
Magnetic Profile
Sensor Electrical
Output Profile, I
I
V
V
OUT
OUT(L)
OUT(H)
I+
V+
V+
OUT
SENSE
ATS642
GND
VCC
4
1
V
CC
(see figure 4).
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
V
R
I
OUT(L)
CC
SENSE
CC(High)
ATS642
V
GND
SUPPLY
VCC
4
1
, to low I
R
V
I
CC
OUT(H)
SENSE
CC(Low)
, as
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