ATS632LSC
HALL-EFFECT
GEAR-TOOTH SENSOR
SUBASSEMBLY
Always order by complete part number, e.g., ATS632LSC .
ZERO-SPEED, SELF-CALIBRATING,
NON-ORIENTED, HALL-EFFECT GEAR-TOOTH SENSOR
Data Sheet
27627.126
The ATS632LSC gear-tooth sensor is an optimized Hall-effect IC/
magnet combination that provides tooth/valley recognition and ex-
tremely accurate tooth edge detection when used with large-pitch
targets. The sensor subassembly consists of a high-temperature
plastic shell that holds together a compound samarium-cobalt magnet,
a single-element self-calibrating Hall-effect IC that has been optimized
to the magnetic circuit, and a voltage regulator. This small package,
with its non-oriented operation, can be easily assembled and used in
conjunction with a number of gear configurations.
The gear sensing technology used for this sensor subassembly 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 minimized by using active offset cancellation circuitry. The digital
algorithm provides zero-speed detection capabilities without the
associated running jitter inherent in classical digital solutions.
The sensor system is ideal for use in gathering speed, position and
profile information of ferrous objects. The device is 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 ATS611LSB is recommended.
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, V
CC
......................... 24 V
Reverse Supply Voltage,
V
RCC
(1 minute max.) ................ -24 V
Output OFF Voltage, V
OUT
................ 24 V
Output Current, I
OUT
.. Internally Limited
Reverse Output Current, I
OUT
........ 50 mA
Package Power Dissipation,
P
D
.................................... See Graph
Operating Temperature Range,
T
A
........................... -40
C to +150
C
Storage Temperature, T
S
............ +170
C
ATS632LSC
continued next page...
Dwg. AH-008
1
2
3
1 = Supply
2 = Output
3 = Ground
PRELIMINARY INFORMATION
(subject to change without notice)
April 8, 1998
ATS632LSC
HALL-EFFECT
GEAR-TOOTH SENSOR
SUBASSEMBLY
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
FEATURES AND BENEFITS
s
Non-Oriented Installation
s
Fully Optimized Gear-Tooth Sensors
s
Single-Chip Sensing IC for High Reliability
s
Zero-Speed Digital Output Representing Target
Profile
s
Extremely Low Timing Accuracy Drift with Tempera-
ture
s
Large Operating Air Gaps
s
Optimized Magnetic Circuit
s
Self-Calibrating Circuitry
with Integrated Offset Cancellation
6-bit A/D Converters to Capture Peaks
Thresholds Proportional to Peak-to-Peak Signals
FUNCTIONAL BLOCK DIAGRAM
600
400
200
40
80
120
160
0
AMBIENT TEMPERATURE IN
C
ALLOWABLE PACKAGE POWER DISSIPATION IN mW
Dwg. GH-065-2
60
100
140
180
20
800
1200
R
JA
= 119
C/W
1000
REG
SUPPLY
1
X
MAGNET
REFERENCE
GENERATOR
THRESHOLD
PEAK
CURRENT
LIMIT
NEGATIVE PEAK
TRACK & HOLD
POSITIVE PEAK
TRACK & HOLD
OUTPUT
LOGIC
OUTPUT
GROUND
Dwg. FH-015-3
2
3
+
GAIN
OFFSET
330 pF
100
W
Copyright 1998, Allegro MicroSystems, Inc.
ATS632LSC
HALL-EFFECT
GEAR-TOOTH SENSOR
SUBASSEMBLY
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Supply Voltage
V
CC
Operating, T
J
< 165
C
6.0
12
24
V
Under-Voltage Lockout
V
CC(UV)
I
OUT
= 5 mA, V
CC
= 0
6 V
5.0
V
Low Output Voltage
V
OUT(L)
I
OUT
= 5 mA, Output ON
0.7
1.6
V
Output Current Limit
I
OUTM
V
OUT
= 12 V
25
45
55
mA
Output Leakage Current
I
OFF
V
OUT
= 24 V, Output OFF
5.0
10
A
Supply Current
I
CC
Output OFF, Target Speed = 0 RPM
9.0
15
mA
Calibration Count
n
cal
Output falling mechanical edges
16
16
16
Pulses
after power on for startup calibration
to be complete
Calibration Update
n
up
Output falling mechanical edges
64
64
64
Pulses
for the threshold calibration to be
complete
Power-On Time
t
po
V
CC
> 6 V
200
500
s
Output Rise Time
t
r
R
L
= 2.5 k
, C
L
= 10 pF
3.0
6.0
s
Output Fall Time
t
f
R
L
= 2.5 k
, C
L
= 10 pF
1.0
3.0
s
ELECTRICAL CHARACTERISTICS over operating voltage and temperature range (unless
otherwise specified).
NOTE: Typical data is at V
CC
= 12 V and T
A
= +25
C and is for design information only.
ATS632LSC
HALL-EFFECT
GEAR-TOOTH SENSOR
SUBASSEMBLY
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Operating Air Gap Range
AG
Operating,
0.3
1.9
mm
Target Speed > 20 RPM
Output Polarity
Operating, Over Tooth
Low
Low
Low
Operating, Over Valley
High
High
High
Timing Accuracy
t
Target Speed < 3500 RPM,
0.25
0.50
0.3 mm
AG
1.9 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
h
t
5.0
mm
Valley Width
(P
C
- 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
(D
o
)
(F)
(T)
(P
C
- T)
(h
t
)
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.
NOTE: Air Gap is defined as the distance from the face of the sensor subassembly to the target.
ATS632LSC
HALL-EFFECT
GEAR-TOOTH SENSOR
SUBASSEMBLY
continued next page...
TYPICAL OPERATING CHARACTERISTICS
3.0
0
0
1.0
1.75
AIR GAP IN MILLIMETERS
RELATIVE TIMING ACCURACY IN DEGREES
Dwg. GH-063-4
0.5
1.5
2.0
1.0
-2.0
-3.0
-1.0
0.25
0.75
1.25
RISING EDGE
-40
C
+25
C
+150
C
TARGET #1
3.0
0
0
1.0
1.75
AIR GAP IN MILLIMETERS
Dwg. GH-063-5
0.5
1.5
2.0
1.0
-2.0
-3.0
-1.0
0.25
0.75
1.25
FALLING EDGE
-40
C
+25
C
+150
C
TARGET #1
RELATIVE TIMING ACCURACY IN DEGREES
3.0
0
0
1.0
1.75
AIR GAP IN MILLIMETERS
Dwg. GH-063-6
0.5
1.5
2.0
1.0
-2.0
-3.0
-1.0
0.25
0.75
1.25
RISING EDGE
-40
C
+25
C
+150
C
TARGET #2
RELATIVE TIMING ACCURACY IN DEGREES
3.0
0
0
1.0
1.75
AIR GAP IN MILLIMETERS
Dwg. GH-063-7
0.5
1.5
2.0
1.0
-2.0
-3.0
-1.0
0.25
0.75
1.25
FALLING EDGE
-40
C
+25
C
+150
C
TARGET #2
RELATIVE TIMING ACCURACY IN DEGREES
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