ATS610LSA and ATS611LSB: Dynamic, Peak-Detecting, Differential Hall-Effect Gear-Tooth Sensor ICs

Data Sheet
27627.101
ATS610LSC
DYNAMIC, PEAK-DETECTING, DIFFERENTIAL
HALL-EFFECT GEAR-TOOTH SENSOR
The ATS610LSC gear-tooth sensor is an optimized Hall IC plus
magnet subassembly that provides a user-friendly solution for digital
gear-tooth sensing applications. The subassembly combines in a
compact high-temperature plastic shell, a samarium-cobalt magnet, a pole
piece, a differential Hall-effect IC that has been optimized to the
magnetic circuit, and a voltage regulator. The sensor can be easily
used in conjunction with a wide variety of gear or target shapes and
sizes.
T
C
U
D
O
Y
T
L
N
R
O
P
The ATS610LSC is designed to provide increased immunity to
false switching in applications that require the sensing of large-tooth
gears (e.g., crank angle or cam angle). The sensor subassembly is
ideal for use in gathering speed, position, and timing information using
gear-tooth-based configurations.
1 = Supply
2 = Output
3 = Ground
1 2
3
Dwg. AH-008
PRELIMINARY INFORMATION
(subject to change without notice)
The gear-sensing technology used for this sensor plus magnet
subassembly is Hall-effect based. The sensor incorporates a
dual-element Hall IC that switches in response to differential magnetic
signals created by the ferrous target. The circuitry contains a patented
track-and-hold peak-detecting circuit to eliminate magnet and system
offset effects. This circuit has the ability to detect relatively fast changes,
such as those caused by gear wobble and eccentricities, and provides
stable operation at extremely low rotation speeds.
E
D
C
E
N
E
U
R
N
E
I
F
T
E
N
R
O
R
C
O
F
S
I
D —
September 3, 1998
ABSOLUTE MAXIMUM RATINGS
over operating temperature range
Supply Voltage, VCC ............................. 24 V
Reverse Supply Voltage,
VRCC (1 minute max.) ................... -24 V
Output OFF Voltage, VOUT .................... 18 V
FEATURES AND BENEFITS
■
■
■
■
■
■
■
Reverse Output Voltage, VOUT .......... -0.5 V
Continuous Output Current, IOUT ...... 25 mA
Package Power Dissipation,
PD ........................................ See Graph
Operating Temperature Range,
TA ............................... -40°C to +150°C
Storage Temperature, TS ................ +170°C
■
■
■
Fully Optimized Differential Digital Gear-Tooth Sensor
Single-Chip Sensing IC for High Reliability
Extremely Low Timing Accuracy Drift with Temperature
Large Operating Air Gaps
Small Mechanical Size
Optimized Magnetic Circuit
Patented Peak-Detecting Filter:
<200 µs Power-On Time
<10 RPM Operation (single-tooth target)
Correct First-Edge Detection
Under-Voltage Lockout
Wide Operating Voltage Range
Defined Power-Up State
Always order by complete part number: ATS610LSC .
ATS610LSC
DYNAMIC, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT
GEAR-TOOTH SENSOR
ALLOWABLE PACKAGE POWER DISSIPATION IN mW
1200
1000
RθJA = 119°C/W
800
600
400
200
0
20
40
80
120
60
100
140
AMBIENT TEMPERATURE IN °C
160
180
Dwg. GH-065-2
FUNCTIONAL BLOCK DIAGRAM
SUPPLY
1
REG
POWER-ON
LOGIC
UVLO
OUTPUT
X
2
E1
MAGNET
X
+
Ð
TRACK &
HOLD
+
Ð
3
GROUND
E2
Dwg. FH-014-2
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 1998, 2002 Allegro MicroSystems, Inc.
ATS610LSC
DYNAMIC, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT
GEAR-TOOTH SENSOR
ELECTRICAL CHARACTERISTICS over operating voltage and temperature range.
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
5.0
12
24
V
HIGH
HIGH
HIGH
Ð
IOUT = 20 mA, VCC = 0 → 5 V
Ð
4.0
Ð
V
IOUT = 20 mA
Ð
350
600
mV
Ð
5.0
15
µA
Supply Voltage
VCC
Operating, TJ < 165°C
Power-On State
POS
VCC = 0 → 5 V
Under-Voltage Lockout
VCC(UV)
Output Saturation Voltage
VOUT(SAT)
Output Leakage Current
IOFF
VOUT = 18 V, Output OFF
Supply Current
ICC
VCC = 6 V, Output OFF
5.5
7.7
11
mA
VCC = 6 V, Output ON
8.5
10.5
13
mA
Ð
Ð
200
µs
Power-On Delay
ton
Output Rise Time
tr
RL = 500 Ω, CL = 10 pF
Ð
0.2
2.0
µs
Output Fall Time
tf
RL = 500 Ω, CL = 10 pF
Ð
0.2
2.0
µs
NOTE: Typical data is at VCC = 12 V and TA = +25°C and is for design information only.
OPERATION over operating voltage and temperature range with reference target (unless
otherwise specified).
Limits
Characteristic
Symbol
Air Gap Range
AG
Test Conditions
Min.
Typ.
Max.
Units
Operating,
Target Speed > 20 RPM
0.4
Ð
1.5
mm
Minimum Air Gap
AGmin
Operating, One-Tooth (180°)
Target, Target Speed = 1000 RPM
Ð
0.25
Ð
mm
Maximum Air Gap
AGmax
Operating, One-Tooth (180°)
Target, Target Speed = 1000 RPM
Ð
2.25
Ð
mm
Target Speed = 1000 RPM,
0.4 mm ≤ AG ≤ 1.5 mm
Ð
±0.5
±1.0
Timing Accuracy
tθ
NOTE: Air Gap is defined as the distance from the face of the sensor subassembly to the target.
°
h
t =
5m
m
ATS610LSC
DYNAMIC, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT
GEAR-TOOTH SENSOR
D o = 115 mm
TARGET
F (THICKNESS) ≥ 3 mm
3
T=
3m
m
m
m
REFERENCE TARGET
AIR GAP
SENSOR
POLE PIECE
SOUTH
PERMANENT
MAGNET
NORTH
1
2
3
Dwg. MH-022 mm
D o = 115 mm
TARGET
T = 180°
(ONE TOOTH)
F (THICKNESS) ≥ 3 mm
E1
ht
=5
mm
AIR GAP
E2
ONE-TOOTH (180°) TARGET
SENSOR
POLE PIECE
SOUTH
PERMANENT
MAGNET
NORTH
1
2
3
Dwg. MH-022-1 mm
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
ATS610LSC
DYNAMIC, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT
GEAR-TOOTH SENSOR
TYPICAL ATS610LSC ELECTRICAL CHARACTERISTICS
14
15
12
14
13
SUPPLY CURRENT IN mA
SUPPLY CURRENT IN mA
11
OUTPUT ON
10
9.0
V
=5V
CC
8.0
7.0
OUTPUT OFF
OUTPUT ON
12
11
10
OUTPUT OFF
9.0
T = 150°C
A
6.0
4.0
-40
8.0
7.0
0
40
80
120
160
200
2.0
AMBIENT TEMPERATURE IN ° C
6.0
10
14
18
SUPPLY VOLTAGE IN VOLTS
Dwg. GH-058-2
Dwg. GH-014-1
175
150
125
OUTPUT SATURATION VOLTAGE IN mV
OUTPUT SATURATION VOLTAGE IN mV
150
I
= 20 mA
OUT
100
75
50
-40
125
100
75
T
A
= 25°C
50
25
0
0
40
80
120
160
200
AMBIENT TEMPERATURE IN °C
0
10
20
30
40
OUTPUT SINK CURRENT IN mA
Dwg. GH-013-1
Dwg. GH-059
continued next pageÉ
ATS610LSC
DYNAMIC, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT
GEAR-TOOTH SENSOR
TYPICAL ATS610LSC OPERATING CHARACTERISTICS
(with reference target)
3.0
3.0
LEADING TARGET EDGE
2.5
RELATIVE ACCURACY IN DEGREES
-40°C
+25°C
+150°C
2.0
1.5
1.0
0.5
0
0
0.5
1.0
2.0
1.5
-40°C
+25°C
+150°C
2.0
1.5
1.0
0.5
0
3.0
2.5
AIR GAP IN MILLIMETERS
0
1.0
0.5
1.5
2.0
AIR GAP IN MILLIMETERS
Dwg. GH-008-13
2.5
3.0
Dwg. GH-008-15
53.0
52.8
-40°C
+25°C
+150°C
52.6
DUTY CYCLE IN PER CENT
RELATIVE ACCURACY IN DEGREES
TRAILING TARGET EDGE
2.5
52.4
52.2
52.0
51.8
51.6
51.4
0
0.5
1.0
1.5
2.0
AIR GAP IN MILLIMETERS
2.5
3.0
Dwg. GH-008-14
continued next pageÉ
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
ATS610LSC
DYNAMIC, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT
GEAR-TOOTH SENSOR
4.0
4.0
3.5
3.5
MAXIMUM AIR GAP IN MILLIMETERS
MAXIMUM AIR GAP IN MILLIMETERS
TYPICAL ATS610LSC OPERATING CHARACTERISTICS
(with reference target) — Continued
3.0
2.5
2.0
-40°C
+25°C
+150°C
1.5
1.0
3.0
2.5
2.0
-40°C
+25°C
+150°C
1.5
1.0
0.5
0.5
0
10
20
30
40
50
60
70
0
500
1000
1500
2000
2500
3000
3500
REFERENCE TARGET SPEED IN RPM
REFERENCE TARGET SPEED IN RPM
Dwg. GH-011-5
Dwg. GH-011-6
DEVICE DESCRIPTION
The ATS610LSC dynamic, peak-detecting, differential
Hall-effect gear-tooth sensor is a Hall IC plus magnet
subassembly 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 application of this sensor is uncomplicated. After
power is applied to the device, it is capable of quickly
providing digital information that is representative of a
rotating gear or specially designed target. 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 2.235
mm (0.088") apart, which senses the magnetic gradient
created by the passing of a ferrous object (a gear tooth).
The two Hall voltages are compared and the difference is
then processed to provide a digital output signal.
The processing circuit uses a patented peak-detection
technique to eliminate magnet and system offsets. This
technique allows coupling and filtering of offsets without
the power-up and settling time disadvantages of classical
high-pass filtering schemes. Here, the peak signal of
every tooth and valley is detected and is used to provide
an instant reference for the operate-point and releasepoint comparators. In this manner, the thresholds are
adapted and referenced to individual signal peaks and
valleys, thereby providing immunity to zero-line variation
due to installation inaccuracies (tilt, rotation, and
off-center placement), as well as for variations caused by
target and shaft eccentricities. The peak detection
concept also allows extremely low-speed operation when
used with small-value capacitors.
ATS610LSC
DYNAMIC, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT
GEAR-TOOTH SENSOR
DEVICE DESCRIPTION — Continued
DIFFERENTIAL
MAGNETIC FLUX
OPERATE
RELEASE
V
OUTPUT
BB
V
OUT(SAT)
Dwg. WH-011
Power-On Operation. The device will power on in the
OFF state (output high) irrespective of the magnetic field
condition. The power-on time of the circuit is no greater
than 5000 µs. The circuit is then ready to accurately
detect the first target edge that results in a HIGH-to-LOW
transition.
Under-Voltage Lockout. When the supply voltage is
below the minimum operating voltage (VCC(UV)), the device
is OFF and stays OFF irrespective of the state of the
magnetic field. This prevents false signals, which may be
caused by under-voltage conditions (especially during turn
on), from appearing at the output.
Output. The device output is an open-collector stage
capable of sinking 25mA. An external pull-up (resistor) to
a supply voltage of not more than 18V must be supplied.
Superior Performance. The ATS610LSC peak-detecting
differential gear-tooth sensor sub-assembly has several
advantages over conventional Hall-effect gear-tooth
sensors.
T
A
= 25°C
-2000
-2500
AIR GAP = 2.5 mm
AIR GAP = 2.0 mm
-3000
AIR GAP = 1.5 mm
-3500
AIR GAP = 1.0 mm
-4000
AIR GAP = 0.5 mm
-4500
-5000
0
10
20
30
40
60
50
ANGLE OF TARGET ROTATION IN DEGREES
Dwg. GH-061-1
Single-element flux maps
showing the impact of varying valley widths
TARGET
DIFFERENTIAL MAGNETIC FIELD IN GAUSS
RELEASE
SINGLE ELEMENT MAGNETIC FIELD IN GAUSS
TARGET
OPERATE
0
T
A
= 25°C
1500
AIR GAP = 0.5 mm
1000
AIR GAP = 1.0 mm
500
0
AIR GAP = 2.5 mm
AIR GAP = 2.0 mm
AIR GAP = 1.5 mm
-500
-1000
-1500
0
10
20
30
40
50
60
ANGLE OF TARGET ROTATION IN DEGREES
Dwg. GH-061
Differential vs. Single-Element Sensing. The differential Hall-element configuration is superior in most applications to the classical single-element gear-tooth sensor.
The single-element configuration commonly used
(Hall-effect sensor mounted on the face of a simple
permanent magnet) requires the detection of a small
signal (often <100G) that is superimposed on a large
back-biased field, often 1500G to 3500G. For most
gear/target configurations, the back-biased field values
Differential flux maps vs. air gaps
change due to concentration effects, resulting in a varying
baseline with air gap, with valley widths, with eccentricities, and with vibration. The differential configuration
cancels the effects of the back-biased field and avoids
many of the issues presented by the single Hall element.
NOTE Ñ 10 G = 1 mT, exactly.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
ATS610LSC
DYNAMIC, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT
GEAR-TOOTH SENSOR
DEVICE DESCRIPTION — Continued
Peak-Detecting vs. AC-Coupled Filters. High-pass
filtering (normal ac coupling) is a commonly used technique for eliminating circuit offsets. AC coupling has
errors at power up because the filter circuit needs to hold
the circuit zero value even though the circuit may power
up over a large signal. Such filter techniques can only
perform properly after the filter has been allowed to settle,
which is typically greater than one second. Also, highpass filter solutions cannot easily track rapidly changing
baselines such as those caused by eccentricities. Peak
detection switches on the change in slope of the signal
and is baseline independent at power up and during
running.
Track-and-Hold Peak Detecting vs. Zero-Crossing
Reference. The usual differential zero-crossing sensors
are susceptible to false switching due to off-center and
tilted installations, which result in a shift in baseline that
changes with air gap. The track-and-hold peak-detection
technique ignores baseline shifts versus air gaps and
provides increased immunity to false switching. In addition, using track-and-hold peak-detecting techniques,
increased air gap capabilities can be expected because a
peak detector utilizes the entire peak-to-peak signal range
as compared to zero-crossing detectors that switch on
fixed thresholds.
NOTE Ñ ÒBaselineÓ refers to the zero-gauss differential where each Hall-effect element is subject to the
same magnetic field strength.
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.
Qualification Test
Test Method and
Test Conditions
Test Length
Samples
Per Lot
Temperature Humidity
Bias Life
JESD22-A101,
TA = 85°C, RH = 85%
1000 hrs
48
Bias Life
JESD22-A108,
TA = 150°C, TJ = 165°C
1000 hrs
48
(Surge Operating Life)
JESD22-A108,
TA = 175°C, TJ = 190°C
168 hrs
48
Autoclave, Unbiased
JESD22-A102,
TA = 121°C, 15 psig
96 hrs
48
High-Temperature
(Bake) Storage Life
JESD22-A103,
TA = 170°C
1000 hrs
48
Temperature Cycle
JESD22-A104
1000 cycles
60
-55°C to +150°C
ESD,
Human Body Model
CDF-AEC-Q100-002
Pre/Post
Reading
3 per
test
Test to failure
All leads > 8 kV
Comments
Device biased for
minimum power
ATS610LSC
DYNAMIC, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT
GEAR-TOOTH SENSOR
APPLICATIONS INFORMATION
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.
NOTE Ñ In application, the terms ÒgearÓ and ÒtargetÓ are
often interchanged. However, ÒgearÓ is preferred when
motion is transferred.
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). The
slope of this magnetic profile also changes with air gap,
resulting in timing accuracy shift with air gap (refer to
typical operating characteristic curves). Valley-to-tooth
transitions will generally provide better accuracy than
tooth-to-valley transitions for large-tooth or large-valley
configurations. For highest accuracy, targets greater than
100mm in diameter should be used.
Air Gap and Tooth Geometry. Operating specifications
are impacted by tooth width (T), valley width (pc - T) and
depth (ht), gear material, and gear face thickness (F). The
target can be a gear or a specially cut shaft-mounted tone
wheel made of stamped ferrous metal. In general, the
following gear or target guidelines must be followed to
achieve greater than 2mm air gap from the face of unit:
Tooth width, T .............................. >2 mm
Valley width, pc - T ...................... >2 mm
(Whole) depth, ht ......................... >3 mm
Gear material ............................... low-carbon steel
Gear face width (thickness), F .... >3 mm
Deviation from these guidelines will result in a reduction of air gap and a deterioration in timing accuracy. For
applications that require the sensing of large-tooth targets,
the optimal sensor choice is the ATS610LSC. Its high
switching thresholds provide increased immunity to false
switching caused by magnetic overshoot and other nonuniformities in the gear or target.
Operation with Fine-Pitch Gears. For targets with a
circular pitch of less than 4mm, a performance improvement can be observed by rotating the front face of the
sensor subassembly. This sensor rotation decreases the
2.235 COS α
Gear Diameter and Pitch. Signal frequency is a direct
function of gear pitch and rotational speed (RPM). The
width of the magnetic signal in degrees and, hence, the
signal slope created by the tooth is directly proportional to
the circumference of the gear (πDo). Smaller diameters
limit the low-speed operation due to the slower rate of
change of the magnetic signal per degree of gear rotation
(here the limitation is the droop of the capacitor versus the
signal change). Larger diameters limit high-speed operation due to the higher rate of change of magnetic signal
per degree of rotation (here the limitation is the maximum
charge rate of the capacitor versus the rate of signal
change). These devices are optimized for a 50mm gear
diameter (signal not limited by tooth width) and speeds of
10 RPM to 8000 RPM.
2.235
α
TARGET FACE WIDTH, F
>2.235 SIN α
Dwg. MH-018-3 mm
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 of the device. For
nonrepetitive target structures, there will be a small but
measureable change in pulse width versus air gap.
Output Polarity. The output of the device will switch from
HIGH to LOW as the leading edge of the target passes
the subassembly from terminal 3 to terminal 1, which
means that the output will be LOW when the unit is facing
a tooth. If rotation is in the opposite direction (terminal 1
to terminal 3), the output of the device will switch from
LOW to HIGH as the leading edge of the target passes
the subassembly, which means that the output will be
HIGH when the unit is facing a tooth.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
ATS610LSC
DYNAMIC, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT
GEAR-TOOTH SENSOR
APPLICATIONS INFORMATION — Continued
Power Supply Protection and Operation From an
Unregulated Power Supply. The internal voltage
regulator provides immunity to power supply variations
between 5 V and 24 V. In automotive applications, where
the device receives its power from an unregulated supply
such as the battery, full protection is provided by the
internal regulator circuit.
Additional applications Information on gear-tooth and
other Hall-effect sensors is provided in the Allegro Integrated and Discrete Semiconductors Data Book or
Application Note 27701.
MECHANICAL INFORMATION
Component
Material
Function
Units
Package
Polyamide 6/12,
33% glass filled
264 psi deflection temp. (DTUL)
Approximate melting temperature
200°C
219°C
Circuit Board
High-temperature FR-4
Glass transition temperature
170°C
Terminals
1 oz Copper
Ð
Terminal Finish
63/37 tin/lead solder plate
Ð
Flame Class Rating
Ð
Ð
Ð
UL94V-0
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.
A
2.235 mm
0.1
Sensor Location (in millimeters)
(sensor location relative to package center is the design
objective)
Dwg. MH-023 mm
ATS610LSC
DYNAMIC, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT
GEAR-TOOTH SENSOR
ATS610LSC DIMENSIONS IN MILLIMETERS
GATE
PROTRUSION
0.3 MAX
1
5.0
A
6.6
1.5 TYP
3
1.0 ¯
PLATED THRU
TYP
5.0
6.0
4.9
0.8
10.0
11.0 ¯
27.5
MAX
3
2
1
1.0
TYP
Dwg. MH-020 mm
Tolerances unless otherwise specified:1 place ±0.1 mm, 2 places ±0.05 mm.
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 design of its products.
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 which may
result from its use.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
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