DISCONTINUED PRODUCT
Replaced by ATS672LSB-LN
Always order by complete part number, e.g., ATS632LSA .
ZERO-SPEED, SELF-CALIBRATING,
NON-ORIENTED, HALL-EFFECT GEAR-TOOTH SENSOR
Data Sheet
27627.125
Dwg. AH-006-2
1
2
3
4
Pin 1 = Supply
Pin 2 = Output
Pin 3 = Test Point
Pin 4 = Ground
The ATS632LSA gear-tooth sensor is an optimized Hall-effect IC/
magnet combination that provides extremely accurate tooth edge
detection when used with large-pitch targets. The sensor module
consists of a high-temperature plastic shell that holds together a
compound samarium-cobalt magnet and a single-element self-calibrat-
ing Hall-effect IC that has been optimized to the magnetic circuit. This
small package, with its non-oriented operation, can be easily as-
sembled on a PC board for complete protection and used in conjunc-
tion with a number of gear configurations.
The gear sensing technology used for this sensor is Hall-effect
based. The sensor incorporates a single-element Hall IC that switches
in response to absolute magnetic signals created by a ferrous target.
The digital output is LOW over a tooth and HIGH over a valley. The
sophisticated processing circuitry contains self-calibrating 6-bit A/D
circuitry that adapts the thresholds to the peak-to-peak signals to
minimize the effects of variation in application air gap on switch-point
timing accuracy. The effects of system and device offsets are mini-
mized by using active offset cancellation circuitry. The digital algorithm
provides zero-speed detection capabilities without the associated
running jitter inherent in classical digital solutions.
This sensor system is ideal for use in gathering speed, position
and profile information of ferrous objects. They are particularly suited
to large tooth/valley sensing applications where accurate timing
accuracy is a desired feature. For applications requiring the sensing of
fine-pitch gears, the ATS610LSA and ATS611LSB are recommended.
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VCC .........................24 V*
Reverse Supply Voltage, VRCC ........ -24 V
Output OFF Voltage, VOUT................. 25 V
Output Current, IOUT .. Internally Limited
Reverse Output Current, IOUT ........ 50 mA
Package Power Dissipation,
PD.................................... See Graph
Operating Temperature Range,
TA............................ -40°C to +150°C
Storage Temperature, TS............ +170°C
* Operation at increased supply voltages with
external circuitry is described in Applications
Information.
ATS632LSA
continued next page…
PRELIMINARY INFORMATION
(subject to change without notice)
August 28, 2002
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
ATS632LSA
HALL-EFFECT
GEAR-TOOTH SENSOR
2
FEATURES AND BENEFITS
■Non-Oriented Installation
■Fully Optimized Gear-Tooth Sensors
■Zero-Speed Digital Output Representing Target
Profile
■Large Operating Air Gaps
■Extremely Low Timing Accuracy Drift with Tempera-
ture
■Correct First-Edge Detection
■Self-Calibrating Circuitry
with Integrated Offset Cancellation
6-bit A/D Converters to Capture Peaks
Thresholds Proportional to Peak-to-Peak Signals
■Optimized Magnetic Circuit
■Single-Chip Sensing IC for High Reliability
FUNCTIONAL BLOCK DIAGRAM
600
400
200
40 80 120 160
0
AMBIENT TEMPERATURE IN °°
°°C
ALLOWABLE PACKAGE POWER DISSIPATION IN mW
Dwg. GH-065-1
60 100 140 18020
800
1000
R
θJA
= 147°C/W
TEST
POINT
3
X
REFERENCE
GENERATOR
THRESHOLD
PEAK
CURRENT
LIMIT
REG
NEGATIVE PEAK
TRACK & HOLD
POSITIVE PEAK
TRACK & HOLD
POWER ON
OUTPUT
LOGIC
OUTPUT
GROUND
SUPPLY
Dwg. FH-015-2
1
2
4
–
+
GAIN
OFFSET
MAGNET
Copyright © 1998, 2002 Allegro MicroSystems, Inc.
ATS632LSA
HALL-EFFECT
GEAR-TOOTH SENSOR
www.allegromicro.com
3
Limits
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Supply Voltage VCC Operating, TJ < 165°C4.5–24 V
Under-Voltage Lockout VCC(UV) IOUT = 20 mA, VCC = 0 → 5 V –4.0 –V
Low Output Voltage VOUT(L) IOUT = 20 mA, Output ON –0.2 0.4 V
Out put Current Limit IOUTM VOUT = 12 V 25 45 55 mA
Out put Leakage Current IOFF VOUT = 24 V, Output OFF –0.2 5.0 µA
Supply Current ICC Output OFF, Target Speed = 0 RPM –9.0 15 mA
Calibration Count ncal Output falling mechanical edges 16 16 16 Pulses
after power on for startup calibration
to be complete
Calibration Update nup Output falling mechanical edges 64 64 64 Pulses
for the threshold calibration to be
complete
Power-On Time tpo VCC > 4.5 V –80 500 µs
Out put Rise Time trRL = 500 Ω, CL = 10 pF –0.2 5.0 µs
Out put Fall Time tfRL = 500 Ω, CL = 10 pF –0.2 5.0 µs
ELECTRICAL CHARACTERISTICS over operating voltage and temperature range (unless
otherwise specified).
NOTE: Typical data is at VCC = 12 V and TA = +25°C and is for design information only.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
ATS632LSA
HALL-EFFECT
GEAR-TOOTH SENSOR
4
Limits
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Operating Air Gap Range AG Operating, 0.3 –2.5 mm
Target Speed > 20 RPM
Output Polarity –Operating, Over Tooth Low Low Low –
Operating, Over Valley High High High –
Timing Accuracy tθTarget Speed < 3500 RPM, –±0.25 ±0.50 °
0.3 mm ≤ AG ≤ 2.0 mm
OPERATION over operating voltage and temperature range with reference target (unless oth-
erwise specified).
Limits
Characteristic Symbol Description Min. Typ. Max. Units
Valley Depth ht–5.0 –mm
Valley Width (PC - T) –5.0 –mm
Tooth Width T –5.0 –mm
Thickness F –5.0 –mm
Eccentricity –Timing accuracy may change ––±0.25 mm
TARGET DESIGN CRITERIA
Diameter Thickness Tooth Width Valley Width Valley Depth
Type (Do) (F) (T) (PC - T) (ht)
Reference Target 84 mm 16 mm 9 mm 13 mm 5 mm
Characterization Target #1 84 mm 16 mm 1 tooth, 180 °5 mm
Characterization Target #2 35 mm 7 mm 1 tooth, 180°6 mm
TARGET DIMENSIONS
NOTE: Timing accuracy data is taken by recalibrating the unit at each air gap.
ATS632LSA
HALL-EFFECT
GEAR-TOOTH SENSOR
www.allegromicro.com
5
continued next page…
3.0
0
0.5 1.5 2.25
AIR GAP IN MILLIMETERS
RELATIVE TIMING ACCURACY IN DEGREES
Dwg. GH-063
1.0 2.0
2.0
1.0
-2.0
-3.0
-1.0
0.75 1.25 1.75
RISING EDGE
-40°C
+25°C
+150°C
TARGET #1
3.0
0
0.5 1.5 2.25
AIR GAP IN MILLIMETERS
Dwg. GH-063-1
1.0 2.0
2.0
1.0
-2.0
-3.0
-1.0
0.75 1.25 1.75
FALLING EDGE
-40°C
+25°C
+150°C
TARGET #1
RELATIVE TIMING ACCURACY IN DEGREES
3.0
0
0.5 1.5 2.25
AIR GAP IN MILLIMETERS
Dwg. GH-063-2
1.0 2.0
2.0
1.0
-2.0
-3.0
-1.0
0.75 1.25 1.75
RISING EDGE
-40°C
+25°C
+150°C
TARGET #2
RELATIVE TIMING ACCURACY IN DEGREES
3.0
0
0.5 1.5 2.25
AIR GAP IN MILLIMETERS
Dwg. GH-063-3
1.0 2.0
2.0
1.0
-2.0
-3.0
-1.0
0.75 1.25 1.75
FALLING EDGE
-40°C
+25°C
+150°C
TARGET #2
RELATIVE TIMING ACCURACY IN DEGREES
TYPICAL OPERATING CHARACTERISTICS
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
ATS632LSA
HALL-EFFECT
GEAR-TOOTH SENSOR
6
TYPICAL OPERATING CHARACTERISTICS — Continued
51.0
49.5
0.5 1.5 2.25
AIR GAP IN MILLIMETERS
DUTY CYCLE IN PER CENT
Dwg. GH-008-3
1.0 2.0
50.5
50.0
48.5
48.0
49.0
0.75 1.25 1.75
-40°C
+25°C
+150°C
TARGET #1
51.0
49.5
0.5 1.5 2.25
AIR GAP IN MILLIMETERS
DUTY CYCLE IN PER CENT
Dwg. GH-008-4
1.0 2.0
50.5
50.0
48.5
48.0
49.0
-40°C
+25°C
+150°C
0.75 1.25 1.75
TARGET #2
+3
+1
-1
1000 3000 5000 70002000 4000 6000
-3
REFERENCE TARGET SPEED IN RPM
RELATIVE TIMING ACCURACY IN DEGREES
Dwg. GH-064-1
+2
0
-2
0
RISING EDGE
0.5 mm
1.0 mm
1.5 mm
2.0 mm
2.5 mm
AIR GAPS
+3
+1
-1
1000 3000 5000 70002000 4000 6000
-3
REFERENCE TARGET SPEED IN RPM
RELATIVE TIMING ACCURACY IN DEGREES
Dwg. GH-064-2
+2
0
-2
0
FALLING EDGE
0.5 mm
1.0 mm
1.5 mm
2.0 mm
2.5 mm
AIR GAPS
ATS632LSA
HALL-EFFECT
GEAR-TOOTH SENSOR
www.allegromicro.com
7
CRITERIA FOR DEVICE QUALIFICATION
All Allegro sensors are subjected to stringent qualification requirements prior to being released to production. To
become qualified, except for the destructive ESD tests, no failures are permitted.
Test Method and Samples
Qualification Test Test Conditions Test Length Per Lot Comments
Temperature Humidity JESD22-A101, 1000 hrs 48 Device biased for
Bias Life TA = 85°C, RH = 85% minimum power
Bias Life JESD22-A108, 1000 hrs 48
TA = 150°C, TJ = 165°C
(Surge Operating Life) JESD22-A108, 168 hrs 48
TA = 175°C, TJ = 190°C
Autoclave, Unbiased JESD22-A102, 96 hrs 48
TA = 121°C, 15 psig
High-Temperature JESD22-A103, 1000 hrs 48
(Bake) Storage Life TA = 170°C
Temperature Cycle JESD22-A104 1000 cycles 48 -55°C to +150°C
ESD, CDF-AEC-Q100-002 Pre/Post 3 per Test to failure
Human Body Model Reading test Pin 3 > 1.5 kV
All leads > 8 kV
APPLICATIONS INFORMATION
Recommended Evaluation Technique. The self-
calibrating feature of the ATS632LSA requires that a
special evaluation technique be used to measure its high-
accuracy performance capabilities. Installation inaccura-
cies are calibrated out at power on; hence, it is extremely
important that the device be re-powered at each air gap
when gathering timing accuracy data.
Self-Calibrating Functions. These sensors are de-
signed to minimize performance variation caused by the
large air gap variations resulting from installation by self-
calibrating at power-on. They are also designed to
minimize performance variation caused by the smaller,
slower air gap changes resulting from temperature
change and gear run-out during continuous operation by
updating the self-calibration periodically (after every 64
output pulses) if necessary. These two functions should
be tested using the following procedure.
1. Set the air gap to the desired value.
2. Power down and then power on the device.
3. Rotate the target at the desired speed.
4. Wait for calibration to complete (16 output pulses to
occur).
5. Monitor output for correct switching and measure
accuracy.
6. Repeat the above for multiple air gaps within the
operating range of the device.
7. This can be repeated over the entire temperature
range.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
ATS632LSA
HALL-EFFECT
GEAR-TOOTH SENSOR
8
APPLICATIONS INFORMATION — Continued
Measurement of the effect of changing air gap after power
on:
1. Set the air gap to the desired value (nominal, for
example). Rotate the target at the desired speed.
Apply power to the module. Wait for 16 output pulses
to occur. Monitor output for correct switching and
measure accuracy.
2. Change the air gap by ± 0.25 mm. Do not re-power
module. Wait for 64 output pulses to occur. Monitor
the output for correct switching and measure accu-
racy.
Device Switch Points. The device switch points are
referenced to the peak-to-peak values of the gain-ad-
justed signal. The comparator thresholds have been
chosen to provide timing accuracy, as well as limited
immunity from mis-detection caused by short valley
conditions or by gear run-out.
Gear Design Criteria.* The system was designed to
work correctly with minimum valley depths of 5 mm and
minimum valley widths of 13 mm. As the valley depth
decreases, the valley field rises above the open-circuit
value of the magnetic circuit when the sensor is at mini-
mum air gap. The same is true when the valley width
decreases. In both cases, the metal mass from the valley
bottom or side walls provides an interference at minimum
air gap and will provide a signal that may be interpreted
as a tooth upon power on. It is important to note that this
anomaly will normally only affect the power-on state of the
device and the self-calibration circuitry will null this
baseline shift when the device is in running mode.
* In application, the terms “gear” and “target” are often
interchanged. However, “gear” is preferred when motion
is transferred.
Signal-Timing Accuracy. Timing accuracy is improved
with larger gear diameters. The magnetic field profile has
a defined spread that narrows in degrees as the target
diameter increases. The slope of this magnetic profile
also changes with air gap. For highest accuracy, targets
greater than 100 mm diameter should be used.
Operation with Fine-Pitch Gears. The self-calibration
routines allow the detection of fine-pitch gears once the
target is rotating. The major issue in these applications is
the impact of gear run-out on the baseline of the magnetic
field. Excessive run-out may result in tooth edges not
being detected.
Signal Duty Cycle. For regular tooth geometries, precise
duty cycle is maintained over the operating air gap and
temperature range due to the good symmetry of the
magnetic switch points of the device.
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 24 V must be supplied.
Output Polarity. The switching of the output is indepen-
dent of the direction of gear rotation.
Power Supply Protection. The device contains an on-
chip regulator and can operate over a wide supply voltage
range (4.5 V to 24 V). For devices that need to operate
from an unregulated power supply, transient protection
must be added externally. For applications being run off a
regulated line, EMI/RFI protection is still required. Incor-
rect protection can result in unexplained pulses on the
output line, providing inaccurate sensing information to
the user.
continued next page…
ATS632LSA
HALL-EFFECT
GEAR-TOOTH SENSOR
www.allegromicro.com
9
continued next page…
APPLICATIONS INFORMATION — Continued
Operation From a Regulated Power Supply. These
devices require minimal protection circuitry during opera-
tion from a low-voltage regulated line. The on-chip
voltage regulator provides immunity to power supply
variations between 4.5 V and 24 V. However, even while
operating from a regulated line, some supply and output
filtering is required to provide immunity to coupled and
injected noise on the supply line. A basic RC low-pass
filter circuit (R1C1) on the supply line and an optional
output capacitor (C2) is recommended for operation in
noisy environments. In extremely noisy environments, a
filter capacitor at pin 3 may also be required. Because the
device has an open collector output, an output pull-up
resistor must be added either at the sensor module or at
the controller.
The protection circuitry can easily be added to a PC
board for use with this device. Provisions have been
made for easy mounting of a PC board on the back of the
unit. PC board installation parallel to the device axis is
also possible.
Dwg. AH-007
1
2
3
4
3
Dwg. EH-008-3A
12 4
Vcc
20 Ω
R
L
0.033 µF100 pF
100 pF
OUTPUT
SUPPLY
C3
C2
C1
R
1
X
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
ATS632LSA
HALL-EFFECT
GEAR-TOOTH SENSOR
10
Additional applications Information on gear-tooth and
other Hall-effect sensors is provided in the Allegro Inte-
grated and Discrete Semiconductors Data Book or
Application Note 27701.
APPLICATIONS INFORMATION — Continued
312 4
Vcc
Dwg. EH-008-2A
20 Ω
R
L
0.033 µF100 pF
100 pF
OUTPUT
SUPPLY
0.1 µF
2.5 kΩ
6.8 V
C
3
C
2
C
1
R
1
R
Z
C
S
X
Operation from an Unregulated Power Supply. In
applications where the device gets its power from an
unregulated supply such as an automotive battery, full
protection is generally required. In addition to supply
regulation, such applications require the device to with-
stand various supply side transients. Specifications for
such transients vary between car manufacturers and
protection circuit design should be optimized for each
application. In the circuit shown below, a simple Zener-
controlled regulator is constructed using discrete compo-
nents. The RC low-pass filter on the supply line (R1C1)
and a low-value supply bypass capacitor (CS) can be
included, if necessary, so as to minimize the susceptibility
to EMI/RFI. The NPN should be chosen with sufficiently
high forward breakdown voltage so as to hold off supply-
side transients. The series diode should be chosen with
sufficiently high reverse breakdown capabilities so as to
withstand the most negative transient. The current-limiting
resistor (RZ) and the Zener diode should be sized for
power dissipation requirements.
ATS632LSA
HALL-EFFECT
GEAR-TOOTH SENSOR
www.allegromicro.com
11
continued next page…
Sensor Location (in millimeters)
(sensor location relative to package center is the design
objective)
0.41
NOM.
0.38
NOM.
0.0076
MIN. PLATING
THICKNESS
Dwg. MH-019A mm
0.48
0.36
0.44
0.35
Lead Cross-Section (in millimeters)
Dwg. MH-018-2 mm
A
0.1
Component Material Function Units
Sensor Face Thermoset epoxy Maximum temperature 170°C*
Plastic Housing Polyamide, 33% glass filled 264 psi deflection temp. (DTUL) 225°C
(Nylon 6, 6) Approximate melting temperature 260°C
Leads Copper ––
Lead Pull –– 8 N
Lead Finish 90/10 tin/lead solder plate –†
Flame Class Rating –– UL94V-0
MECHANICAL INFORMATION
*Temperature excursions to 225 °C for 2 minutes or less are permitted.
†All industry-accepted soldering techniques are permitted for these modules provided the indicated maximum
temperature for each component (e.g., sensor face, plastic housing) is not exceeded. Reasonable dwell times,
which do not cause melting of the plastic housing, should be used.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
ATS632LSA
HALL-EFFECT
GEAR-TOOTH SENSOR
12
DIMENSIONS IN MILLIMETERS
A
Dwg. MH-017A mm
1 2 3 4
9.0
8.3
8.0
SEE NOTE
2.0
7.25
5.00 9.0
0.9 DIA
3.0 NOM
0.38
3.9
0.41
1.27
TYP
Tolerances unless otherwise specified:1 place ±0.1 mm, 2 places ±0.05 mm.
NOTE — Nominal dimension and tolerances dependent on package material. Contact factory.
The products described herein are manufactured under one or
more of the following U.S. patents: 5,045,920; 5,264,783; 5,442,283;
5,389,889; 5,581,179; 5,517,112; 5,619,137; 5,621,319; 5,650,719;
5,686,894; 5,694,038; 5,729,130; 5,917,320; and other patents
pending.
Allegro MicroSystems, Inc. reserves the right to make, from time to
time, such departures from the detail specifications as may be
required to permit improvements in the performance, reliability, or
manufacturability of its products. Before placing an order, the user is
cautioned to verify that the information being relied upon is current.
Allegro products are not authorized for use as critical components
in life-support appliances, devices, or systems without express written
approval.
The information included herein is believed to be accurate and
reliable. However, Allegro MicroSystems, Inc. assumes no responsi-
bility for its use; nor for any infringements of patents or other rights of
third parties that may result from its use.
