ATS632LSC: Zero-Speed, Self-Calibrating, Non-Oriented, Hall-Effect Gear-Tooth Sensor IC

Data Sheet
27627.126a
ATS632LSC
ZERO-SPEED, SELF-CALIBRATING,
NON-ORIENTED, HALL-EFFECT GEAR-TOOTH SENSOR IC
The ATS632LSC gear-tooth sensor IC is an optimized Hall-effect IC
that provides tooth/valley recognition and extremely accurate
tooth edge detection when used with large-pitch
targets. This sensor subassembly consists of a high-temperature
plastic shell that holds together a compound samarium-cobalt pellet,
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.
1 = Supply
2 = Output
3 = Ground
1 2
3
Dwg. AH-008
PRELIMINARY INFORMATION
T
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P EO
The gear sensing technology used for this sensor subassembly is
Hall-effect based. The circuit 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.
D
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(subject to change without notice)
April 8, 1998
ABSOLUTE MAXIMUM RATINGS
The device 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.
Supply Voltage, VCC ......................... 24 V
Reverse Supply Voltage,
VRCC (1 minute max.) ................ -24 V
continued next page…
Output OFF Voltage, VOUT ................ 24 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
Always order by complete part number, e.g., ATS632LSC .
ATS632LSC
HALL-EFFECT
GEAR-TOOTH SENSOR IC
1200
■
■
■
1
SUPPLY
1000
RθJA = 119°C/W
800
600
400
200
0
20
40
60
80
100
120
140
AMBIENT TEMPERATURE IN ° C
FUNCTIONAL BLOCK DIAGRAM
REG
MAGNET
100 Ω
GAIN
X
2
–
OUTPUT
THRESHOLD
+
OFFSET
PEAK
OUTPUT
LOGIC
■
Non-Oriented Installation
Fully Optimized Gear-Tooth Sensor IC
Single-Chip Sensing IC for High Reliability
Zero-Speed Digital Output Representing Target
Profile
Extremely Low Timing Accuracy Drift with Temperature
Large Operating Air Gaps
Optimized Magnetic Circuit
Self-Calibrating Circuitry
with Integrated Offset Cancellation
6-bit A/D Converters to Capture Peaks
Thresholds Proportional to Peak-to-Peak Signals
REFERENCE
GENERATOR
■
■
■
■
ALLOWABLE PACKAGE POWER DISSIPATION IN mW
FEATURES AND BENEFITS
CURRENT
LIMIT
330 pF
POSITIVE PEAK
TRACK & HOLD
3
GROUND
NEGATIVE PEAK
TRACK & HOLD
Dwg. FH-015-3
115 Northeast Cutoff, Box 15036
W
Worcester,
Massachusetts 01615-0036 (508) 853-5000
Copyright © 2001, 2002 Allegro MicroSystems, Inc.
160
180
Dwg. GH-065-2
ATS632LSC
HALL-EFFECT
GEAR-TOOTH SENSOR IC
ELECTRICAL CHARACTERISTICS over operating voltage and temperature range (unless
otherwise specified).
Limits
Characteristic
Supply Voltage
Symbol
VCC
Test Conditions
Operating, TJ < 165°C
Min.
Typ.
Max.
Units
6.0
12
24
V
Under-Voltage Lockout
VCC(UV)
IOUT = 5 mA, VCC = 0 → 6 V
–
5.0
–
V
Low Output Voltage
VOUT(L)
IOUT = 5 mA, Output ON
–
0.7
1.6
V
Output Current Limit
IOUTM
VOUT = 12 V
25
45
55
mA
Output Leakage Current
I OFF
VOUT = 24 V, Output OFF
–
5.0
10
µA
Supply Current
ICC
Output OFF, Target Speed = 0 RPM
–
9.0
15
mA
Calibration Count
ncal
Output falling mechanical edges
after power on for startup calibration
to be complete
16
16
16
Pulses
Calibration Update
n up
Output falling mechanical edges
for the threshold calibration to be
complete
64
64
64
Pulses
Power-On Time
tpo
VCC > 6 V
–
200
500
µs
Output Rise Time
tr
RL = 2.5 kΩ, CL = 10 pF
–
3.0
6.0
µs
Output Fall Time
tf
RL = 2.5 kΩ, CL = 10 pF
–
1.0
3.0
µs
NOTE: Typical data is at VCC = 12 V and TA = +25°C and is for design information only.
ATS632LSC
HALL-EFFECT
GEAR-TOOTH SENSOR IC
OPERATION over operating voltage and temperature range with reference target (unless otherwise specified).
Limits
Characteristic
Operating Air Gap Range
Output Polarity
Timing Accuracy
Symbol
AG
–
tθ
Test Conditions
Min.
Typ.
Max.
Units
Operating,
Target Speed > 20 RPM
0.3
–
1.9
mm
Operating, Over Tooth
Low
Low
Low
–
Operating, Over Valley
High
High
High
–
–
±0.25
±0.50
°
Target Speed < 3500 RPM,
0.3 mm ≤ AG ≤ 1.9 mm
NOTE: Air Gap is defined as the distance from the face of the subassembly to the target.
TARGET DESIGN CRITERIA
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
–
–
–
±0.25
mm
Timing accuracy may change
TARGET DIMENSIONS
Diameter
( Do )
Thickness
(F)
Tooth Width
(T)
Valley Width
(PC - T)
Valley Depth
(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
Type
NOTE: Timing accuracy data is taken by recalibrating the unit at each air gap.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
ATS632LSC
HALL-EFFECT
GEAR-TOOTH SENSOR IC
TYPICAL OPERATING CHARACTERISTICS
3.0
TARGET #1
TARGET #1
2.0
RELATIVE TIMING ACCURACY IN DEGREES
RELATIVE TIMING ACCURACY IN DEGREES
3.0
-40°C
+25°C
+150°C
1.0
RISING EDGE
0
-1.0
-2.0
-3.0
0
0.25
0.5
0.75
1.0
1.25
1.5
AIR GAP IN MILLIMETERS
FALLING EDGE
-1.0
-2.0
0
0.25
Dwg. GH-063-4
0.5
0.75
1.0
1.25
1.5
1.75
Dwg. GH-063-5
3.0
TARGET #2
2.0
RELATIVE TIMING ACCURACY IN DEGREES
RELATIVE TIMING ACCURACY IN DEGREES
0
AIR GAP IN MILLIMETERS
3.0
-40°C
+25°C
+150°C
1.0
0
RISING EDGE
-1.0
-2.0
-3.0
1.0
-3.0
1.75
-40°C
+25°C
+150°C
2.0
0
0.25
0.5
0.75
1.0
AIR GAP IN MILLIMETERS
1.25
1.5
1.75
Dwg. GH-063-6
TARGET #2
-40°C
+25°C
+150°C
2.0
1.0
0
FALLING EDGE
-1.0
-2.0
-3.0
0
0.25
0.5
0.75
1.0
AIR GAP IN MILLIMETERS
1.25
1.5
1.75
Dwg. GH-063-7
continued next page…
ATS632LSC
HALL-EFFECT
GEAR-TOOTH SENSOR IC
TYPICAL OPERATING CHARACTERISTICS — Continued
51.0
51.0
TARGET #2
TARGET #1
50.0
49.5
49.0
50.0
49.5
49.0
48.5
48.5
48.0
0
0.25
0.5
0.75
1.0
1.25
AIR GAP IN MILLIMETERS
1.5
1.75
48.0
0.5
0.25
Dwg. GH-008-11
0.75
1.0
1.25
1.5
1.75
Dwg. GH-008-12
+3
RELATIVE TIMING ACCURACY IN DEGREES
RELATIVE TIMING ACCURACY IN DEGREES
0
AIR GAP IN MILLIMETERS
+3
+2
+1
0
RISING EDGE
-1
AIR GAPS
0.5 mm
1.0 mm
1.5 mm
2.0 mm
-2
-3
-40°C
+25°C
+150°C
50.5
-40°C
+25°C
+150°C
DUTY CYCLE IN PER CENT
DUTY CYCLE IN PER CENT
50.5
0
1000
2000
3000
4000
5000
REFERENCE TARGET SPEED IN RPM
6000
7000
Dwg. GH-064-3
+2
+1
0
FALLING EDGE
-1
AIR GAPS
0.5 mm
1.0 mm
1.5 mm
2.0 mm
-2
-3
0
1000
2000
3000
4000
5000
REFERENCE TARGET SPEED IN RPM
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
6000
7000
Dwg. GH-064-4
ATS632LSC
HALL-EFFECT
GEAR-TOOTH SENSOR IC
CRITERIA FOR DEVICE QUALIFICATION
All Allegro devices 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
Sam ples
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
48
-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
APPLICATIONS INFORMATION
Recommended Evaluation Technique. The selfcalibrating feature of the ATS632LSC requires that a
special evaluation technique be used to measure its highaccuracy performance capabilities. Installation inaccuracies 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. This subassembly is
designed to minimize performance variation caused by
the large air gap variations resulting from installation by
self-calibrating at power-on. It is 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.
ATS632LSC
HALL-EFFECT
GEAR-TOOTH SENSOR IC
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 subassembly. 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
subassembly. Wait for 64 output pulses to occur.
Monitor the output for correct switching and measure
accuracy.
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.
Device Switch Points. The device switch points are
referenced to the peak-to-peak values of the gain-adjusted 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.
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 either at the IC
or at the controller.
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 device is at minimum 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.
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 Polarity. The switching of the output is independent
of the direction of gear rotation.
Power Supply Protection. These devices require
minimal protection circuitry during operation from a lowvoltage line. The internal voltage regulator provides
immunity to power supply variations between 6 V and
24 V. EMI/RFI protection is provided as part of the
internal regulator. In extremely noisy environments,
additional (external) components may be required.
Additional applications Information on gear-tooth and
other Hall-effect devices is provided in the Allegro Integrated and Discrete Semiconductors Data Book or
Application Note 27701.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
ATS632LSC
HALL-EFFECT
GEAR-TOOTH SENSOR IC
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
–
–
Terminal Finish
63/37 tin/lead solder plate
–
†
Flame Class Rating
–
–
UL94V-0
† All industry-accepted soldering techniques are permitted for these subassemblies provided the indicated
maximum temperature for each component (e.g., package face, plastic housing) is not exceeded. Reasonable
dwell times, which do not cause melting of the plastic housing, should be used.
Element Location (in millimeters)
(element location relative to package center is the design
objective)
A
0.1
Dwg. MH-021 mm
continued next page…
ATS632LSC
HALL-EFFECT
GEAR-TOOTH SENSOR IC
DIMENSIONS IN MILLIMETERS
GATE
PROTRUSION
0.3 MAX
1
5.0
A
6.6
1.5 TYP
3
1.0 Ø
PLATED THRU
TYP
5.0
6.0
4.9
0.8
10.0
11.0 Ø
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.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
ATS632LSC
HALL-EFFECT
GEAR-TOOTH SENSOR IC
This page intentionally left blank
ATS632LSC
HALL-EFFECT
GEAR-TOOTH SENSOR IC
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
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