Page 1
ATS622LSB
TRUE ZERO-SPEED
HALL-EFFECT GEAR-TOOTH SENSOR
Data Sheet
27627.105
1
2
3
4
Pin 1 = Supply
Pin 2 = Output
Pin 3 = No Connection
Pin 4 = Ground
Dwg. AH-006-6
PRELIMINARY INFORMATION
(subject to change without notice)
October 20, 2000
ABSOLUTE MAXIMUM RATINGS
at T
= 25°C
A
Supply Voltage, VCC........................ 26.5 V*
Reverse Supply Voltage, V
Continuous Output Current, I
Reverse Output Current, I
Package Power Dissipation,
PD.......................................... See Graph
Operating Temperature Range,
TA............................. -40°C to +150°C*
Junction Temperature,
(continuous), TJ.......................... +165°C
(100 s), TJM................................ +180°C
Storage Temperature, TS................... +170°C
* Operation at increased supply voltages with
external circuitry is described in Applications
Information. Devices for operation at increased temperatures are available on special
order.
............ -24 V
RCC
OUT
.......... 50 mA
ROUT
....... 20 mA
The ATS622LSB is an optimized Hall-effect sensing integrated
circuit and magnet combination that provides a user-friendly solution
for true zero-speed digital gear-tooth sensing. The sensor subassembly
consists of a plastic shell that holds together a samarium-cobalt magnet,
a pole piece, and a Hall-effect sensor that has been optimized to the
magnetic circuit. This small package can be easily assembled and used
in conjunction with a wide variety of gear shapes and sizes.
The integrated circuit incorporates a dual-element Hall-effect
sensor and signal processing that switches in response to differential
magnetic signals created by the ferrous gear teeth. The circuitry
contains a sophisticated digital circuit to eliminate magnet and system
offsets and to achieve true zero-speed operation (manufactured under
U.S. Pat. 5,917,320). A-to-D and D-to-A converters are used to adjust
the device gain at power on and to allow air-gap independent switching,
which greatly reduces vibration sensitivity of the device.
This sensor system is ideal for obtaining transmission and crank
information using gear-tooth-based configurations.
FEATURES AND BENEFITS
■ Tight timing accuracy over temperature
■ True zero-speed operation
■ Air-gap independent switch points
■ High vibration immunity
■ Extremely precise duty cycle signal with temperature
■ Large operating air gaps
■ Defined power-on state
■ Wide operating voltage range
■ Digital output representing gear profile
■ Single-chip sensing IC for high reliability
■ Small mechanical size (9 mm diameter x 7 mm length)
■ Optimized magnetic circuit
■ <200 µs power-on time
■ AGC and reference-adjust circuit
■ Under-voltage lockout
Some restrictions may apply to certain types of sales.
Contact factory for details.
Always order by complete part number: ATS622LSB .
Page 2
ATS622LSB
TRUE ZERO-SPEED,
GEAR-TOOTH SENSOR
FUNCTIONAL BLOCK DIAGRAM
MAGNET
Dwg. FH-019-3
1000
SUPPLY1
3
NO (INTERNAL)
CONNECTION
32 V
REG
X
E1
X
E2
–
+
–
REF
+
POSITIVE PEAK
DIGITAL PROC.
NEGATIVE PEAK
DIGITAL PROC.
UVLO
POWER-ON
LOGIC
REFERENCE
GENERATOR
THRESHOLD
COMPARATORS
–
+
–
+
LOGIC
OUTPUT
OUTPUT
2
GROUND
4
800
1
0
0
H
O
600
400
200
0
ALLOWABLE PACKAGE POWER DISSIPATION IN mW
40 80 120
C
60 100 140 18020
AMBIENT TEMPERATURE IN °C
U
R
O
N
S
T
M
IN
U
O
U
S
2
R
θJA
= 147°C/W
A
X
.
160
Dwg. GH-065-6
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2000, Allegro MicroSystems, Inc.
Page 3
ATS622LSB
TRUE ZERO-SPEED,
GEAR-TOOTH SENSOR
ELECTRICAL CHARACTERISTICS at TA = +25°C (unless otherwise noted).
Limits
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Supply Voltage V
CC
Operating, TJ < 165°C 4.5 12 24 V
Power-On State POS VCC = 0 → 5 V OFF OFF OFF –
Under-Voltage Lockout V
Low Output Voltage V
OUT(SAT)
Output Current Limit I
Output Leakage Current I
Supply Current I
CC(UV)
OUTM
OFF
CC
VCC = 0 → 5 V 4.1 4.2 4.3 V
I
= 20 mA – 0.2 0.4 V
OUT
V
= 12 V 254555 mA
OUT
V
= 24 V – 0.2 10 µA
OUT
Output off 3.5 7.0 12 mA
Output on 5.0 8.5 14 mA
Output Rise Time t
Output Fall Time t
Power-On Time t
Zener Voltage V
r
f
on
Z
RL = 500 Ω, CL = 10 pF – 0.2 5.0 µs
RL = 500 Ω, CL = 10 pF – 0.2 5.0 µs
Reference gear, <100 rpm – – 200 µs
IZT = TBD – 32 – V
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3
Page 4
ATS622LSB
TRUE ZERO-SPEED,
GEAR-TOOTH SENSOR
OPERATION over operating voltage and temperature range with reference target (unless otherwise noted)
Limits
Characteristic Symbol Description Min. Typ. Max. Units
Air Gap Range AG Operating, target speed > 20 RPM 0.5 – 2.5 mm
Calibration Cycle n
cal
Output edges before which 1 1 1 Edge
calibration is completed*
Calibration Update n
r
Output falling edges for startup 128 128 128 Edges
calibration to be complete
Minimum Speed n
Maximum Speed n
Timing Accuracy t
min
max
θ
60 teeth per second = 1 r/s – 133 – r/s
Target speed = 1000 rpm, – ±0.2 ±0.5 °
–0– r/s
0.5 mm < AG < 2.5 mm
* Non-uniform magnetic profiles may require additional output pulses before calibration is completed.
REFERENCE GEAR DIMENSIONS (60-0)
Limits
Characteristic Symbol Description Min. Typ. Max. Units
Diameter D
O
Tooth Width T – 3.0 – mm
– 120 – mm
Valley Width (pC – T) – 3.0 – mm
Valley Depth h
t
–3.0– mm
Thickness F 3.0 – – mm
4
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Page 5
TYPICAL CHARACTERISTICS
ATS622LSB
TRUE ZERO-SPEED,
GEAR-TOOTH SENSOR
12
10
8.0
6.0
4.0
SUPPLY CURRENT IN mA
2.0
0
0
5
SUPPLY VOLTAGE IN VOLTS
12
10
8.0
6.0
4.0
B > BOP
TA = 150°C
A = +25°C
T
A = -40°C
T
10
15 20 25
30
Dwg. GH-041-4
SUPPLY CURRENT IN mA
2.0
0
0
5
SUPPLY VOLTAGE IN VOLTS
10
15 20 25
B < B
TA = 150°C
A
= +25°C
T
A
= -40°C
T
RP
30
Dwg. GH-041-3
1.2
1.0
0.8
0.6
0.4
SUPPLY CURRENT IN mA
0.2
0
-30
-25
REVERSE SUPPLY VOLTAGE IN VOLTS
-20
TA = 150°C
A = +25°C
T
A = -40°C
T
-15 -10 -5.0
Dwg. GH-031-2
350
300
250
200
150
100
50
B > B
TA = 150°C
A
= +25°C
T
A
= -40°C
T
OP
OUTPUT SATURATION VOLTAGE IN mV
0
0
0
5.0
10 15 20 25
OUTPUT SINK CURRENT IN mA
Dwg. GH-059-1
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5
Page 6
ATS622LSB
TRUE ZERO-SPEED,
GEAR-TOOTH SENSOR
DEVICE DESCRIPTION
Subassembly description. The ATS622LSB true
zero-speed gear-tooth sensor system is a Hall IC plus
magnet configuration that is fully optimized to provide
digital detection of gear-tooth* edges in a small package
size. The sensor is packaged in a miniature plastic housing
that has been optimized for size, ease of assembly, and
manufacturability. High operating-temperature materials
are used in all aspects of construction.
The use of the sensor is simple. After correct power is
applied to the component, it is capable of instantly providing digital information that is representative of the profile
of a rotating gear. No additional optimization or processing circuitry is required. This ease of use should reduce
design time and incremental assembly costs for most
applications.
Sensing technology. The gear-tooth sensor subassembly contains a single-chip differential Hall-effect sensor
IC, a samarium-cobalt magnet, and a flat ferrous pole
piece. The Hall IC consists of two Hall elements spaced
2.2 mm apart, located so as to measure the magnetic
gradient created by the passing of a ferrous object (a gear
tooth). The two elements measure the field gradient and
convert it to a voltage that is then processed to provide a
digital output signal.
SENSOR
POLE PIECE
SOUTH
PERMANENT
MAGNET
NORTH
1 2 3 4
* In application, the terms “gear” and “target” are often interchanged. However, “gear” is preferred when motion is transferred.
Dwg. MH-016-4
Internal electronics. The ATS622LSB is a self-
calibrating sensor that contains two Hall-effect elements, a
temperature-compensated amplifier, and offset cancellation circuitry. Also contained in the device is a voltage
regulator to provide supply rejection over the operating
voltage range.
The self-calibrating circuitry is unique. After power up,
the device measures the peak-to-peak magnetic signal and
adjusts the gain using an on-chip D-to-A converter to
make the internal signal amplitude constant independent of
the installation air gap of the sensor. This feature allows
air-gap-independent operational characteristics.
1000
800
600
400
200
0
-200
-400
-600
-800
DIFFERENTIAL MAGNETIC FIELD IN GAUSS
-1000
RELATIVE TARGET POSITION
AG = 2.75 mm
0.25 mm INTERVALS
AG = 0.25 mm
Dwg. GH-061-2
Magnetic signal before gain control
1000
800
600
400
200
0
-200
-400
ELECTRICAL SIGNAL IN mV
-600
-800
-1000
RELATIVE TARGET POSITION
AG = 2.75 mm
AG = 0.25 mm
Dwg. GH-061-3
Magnetic signal after gain control
6
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Page 7
GEAR-TOOTH SENSOR
DEVICE DESCRIPTION — Continued
ATS622LSB
TRUE ZERO-SPEED,
In addition to the gain control circuitry, the device also
has provisions to zero out chip, magnet, and installation
offsets. This is accomplished using two D-to-A converters
that capture the peak and valley of the signal and use them
as a reference for the switching comparator. This allows
the switch points to be precisely controlled independent of
air gap or temperature.
The two Hall transducers and the electronics are integrated on a single silicon substrate using a proprietary
BiCMOS process.
Solution advantages. The ATS622LSB true zero-
speed detecting gear-tooth sensor subassembly uses a
differential Hall-element configuration. This configuration
is superior in most applications to a classical singleelement GTS. The single-element configuration commonly used requires the detection of an extremely small
signal (often <100 G) that is superimposed on an extremely large back biased field, often 1500 G to 3500 G.
For most gear configurations, the back-biased field values
change due to concentration effects, resulting in a varying
baseline with air gap, with valley widths, with eccentricities, and with vibration. The differential configuration
eliminates the effects of the back-biased field through
subtraction and, hence, avoids the issues presented by the
single Hall element. The signal-processing circuitry also
greatly enhances the functionality of this device. Other
advantages are
■ temperature drift — changes in temperature do not
greatly affect this device due to the stable amplifier design
and the offset rejection circuitry,
■ timing accuracy/duty cycle variation due to air gap —
the accuracy variation caused by air-gap changes is
minimized by the self-calibration circuitry. A two-to-three
times improvement can be seen over conventional zerocrossing detectors,
■ dual edge detection — because this device references
the positive and negative peaks of the signal, dual edge
detection is guaranteed,
■ tilted or off-center installation — traditional differential sensors will switch incorrectly due to baseline changes
versus air gap caused by tilted or off-center installation.
The self-calibration feature will eliminate the effect of
tilted installation by readjusting the switch points to the
new signal,
■ large operating air gaps — operating air gaps greater
than 2.5 mm are easily achievable with this device due to
the sensitive switch points after start up,
■ immunity to magnetic overshoot — the air-gap
independent hysteresis minimizes the impact of overshoot
on the switching of device output,
■ response to surface defects in the gear — the gainadjust circuitry reduces the effect of minor gear anomalies
that would normally causes false switching,
■ immunity to vibration and backlash — the gain-adjust
circuitry keeps the hysteresis of the device roughly proportional to the peak-to-peak signal. This allows the device to
have good immunity to vibration even when operating at
close air gaps,
■ immunity to gear run out — the differential-sensor
configuration eliminates the base-line variations caused by
gear run out, and
■ use with stamped-gear configurations — the highsensitivity switch points allow the use of stamped gears.
The shallow mechanical slopes created by the stamping
process create an acceptable magnetic gradient down to
zero speed. The surface defects caused by stamping the
gear are ignored through the use of gain-control circuitry.
Operation versus air-gap/tooth geometry. Operating specifications are impacted by tooth size, valley size
and depth, gear material, and gear thickness. In general,
the following guidelines should be followed to achieve
greater than 2 mm air gap from the face of unit:
■ tooth width (T) > 2 mm;
■ valley width (p
■ valley depth (h
■ gear thickness (F) > 3 mm; and the
■ gear material must be low-carbon steel.
Signal duty cycle. For regular tooth geometry, precise
duty cycle is maintained over the operating air-gap and
temperature range due to an extremely good symmetry in
the magnetic switch points of the device. For irregular
tooth geometry, there will a small but noticeable change in
pulse width versus air gap.
- T) > 2 mm;
C
) > 2 mm;
t
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7
Page 8
ATS622LSB
TRUE ZERO-SPEED,
GEAR-TOOTH SENSOR
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. 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
CC(UV)
), the 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 subassembly is a short-circuitprotected 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
subassembly 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
subassembly, which means that the output voltage will be
low when the unit is facing a tooth.
1
2
3
4
Dwg. AH-006-1
APPLICATIONS INFORMATION
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 unregulated 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.
4
3
2
1
Dwg. AH-007
8
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Page 9
TRUE ZERO-SPEED,
GEAR-TOOTH SENSOR
APPLICATIONS INFORMATION — Continued
ATS622LSB
Recommended evaluation technique. The self-
calibrating feature of the ATS622LSB 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 repowered at each air gap
when gathering timing accuracy data.
The ATS622LSB is designed to minimize performance
variation (caused by the large air-gap variations resulting
from installation) by self-calibrating at power-on. These
functions should be tested using the procedures described
below.
Timing accuracy capabilities after correct self-calibration can be measured as follows:
1. Set the air gap to the desired value.
2. Power down and then power up the device.
3. Rotate the gear at the desired speed.
4. Wait for calibration to complete (128 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 operating temperature range.
2.2
There is an internal update algorithm that will maintain
the correct duty cycle as air gap changes with temperature.
Large changes in air gap will require the part to reset (by
cycling power) to maintain the correct duty cycle.
Measurement of the effect of changing air gap after
power up:
1. Set the air gap to the desired value (nominal, for
example). Rotate the target at the desired speed. Apply
power to the subassembly. Wait for 128 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 the
subassembly. Wait for update algorithm to finish adjusting thresholds, typically 2 to 3 rotations on a 60-tooth gear.
Operation with fine-pitch gears. For targets with a
circular pitch of less than 4 mm, a performance improvement can be observed by rotating the front face of the
sensor subassembly. This sensor rotation decreases the
effective sensor-to-sensor spacing and increases the
capability of detecting fine tooth or valley configurations,
provided that the Hall elements are not rotated beyond the
width of the target.
α
2.2 COS
www.allegromicro.com
A
TARGET FACE WIDTH, F
>2.2 SIN
α
α
A
Dwg. MH-018-5 mm
9
Page 10
ATS622LSB
TRUE ZERO-SPEED,
GEAR-TOOTH SENSOR
APPLICATIONS INFORMATION — Continued
Signal timing accuracy. The magnetic field profile
width is defined by the sensor element spacing and narrows in degrees as the target diameter increases. This
results in improved timing accuracy performance for larger
gear diameters (for the same number of gear teeth).
Valley-to-tooth transistions will generally provide better
accuracy than tooth-to-valley transitions for large-tooth or
large-valley configurations. For highest accuracy, targets
greater than 100 mm in diameter should be used.
Signal duty cycle. For repetitive target structures,
precise duty cycle is maintained over the operating air gap
and temperature range due to an extremely good symmetry
in the magnetic switch points and the internal self calibration of the device. For irregular tooth geometries, there
will be a small but measureable change in pulse width
versus air gap.
Additional applications Information on gear-tooth
and other Hall-effect sensors is also available in the “HallEffect IC Applications Guide”, which can be found in the
latest issue of the Allegro MicroSystems Electronic Data
Book, AMS-701 or Application Note 27701, or at
www.allegromicro.com
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 60 -55°C to +150°C
ESD, CDF-AEC-Q100-002 Pre/Post 3 per Test to failure
Human Body Model Reading test All leads > x kV
10
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Page 11
ATS622LSB
TRUE ZERO-SPEED,
GEAR-TOOTH SENSOR
MECHANICAL INFORMATION
Component Material Function Units
Sensor Face Thermoset epoxy Maximum temperature 170°C*
Plastic Housing Thermoplastic PBT 264 psi deflection temp. (DTUL) 204°C
66 psi deflection temp. (DTUL) 216°C
Approximate melting temperature 225°C
Leads Copper — —
Lead Finish 90/10 tin/lead solder plate — †
Lead Pull — — 8 N
* Temperature excursions to 225°C for 2 minutes or less are permitted.
† All industry-accepted soldering techniques are permitted for these subassemblies 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.
Sensor location (in millimeters)
(sensor location relative to package center is the design objective)
2.2 mm
Lead cross section (in millimeters)
A
Dwg. MH-018-4 mm
0.48
0.36
0.41
NOM.
0.0076
MIN. PLATING
THICKNESS
0.38
NOM.
Dwg. MH-019A mm
0.44
0.35
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Allegro
11
Page 12
ATS622LSB
TRUE ZERO-SPEED,
GEAR-TOOTH SENSOR
DIMENSIONS IN MILLIMETERS
DIA
8.8
7.0
7.0
2.0
3.0
NOM
0.38
1.27
TYP
1 2 3 4
0.41
0.9
Tolerances, unless otherwise specified: 1 place ±0.1 mm, 2 places ±0.05 mm.
3.9
A
8.968.09
Dwg. MH-017-1B mm
12
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 responsibility for its use; nor for any infringements of patents or other rights of
third parties that may result from its use.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Page 13
ATS622LSB
TRUE ZERO-SPEED,
GEAR-TOOTH SENSOR
ADAPTIVE THRESHOLD SENSORS
SELECTION GUIDE
Part Operating
Number Temp. Range Key Applications & Salient Features
ATS610LSA -40°C to +150°C
ATS611LSB -40°C to +150°C Fine-pitch, large air gap, speed sensing – transmission speed, ABS,
ATS612JSB -40°C to +115°C Large/small-tooth speed sensing,
ATS632LSA -40°C to +150°C Large-tooth, gear-position sensing – cam angle
ATS640JSB -40°C to +115°C Small-tooth gear-position sensing for two-wire applications,
Large-tooth, speed sensing – crank angle, cam angle,
differential, peak-detecting geartooth sensor (to 20 rpm w/ 0.22 µF)
differential, peak-detecting geartooth sensor (to 20 rpm w/ 0.22 µF)
differential, peak-detecting geartooth sensor (to 20 rpm w/ 0.22 µF)
zero speed
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13
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