ALLEGRO ATS612LSG

ATS612LSG
DYNAMIC, SELF-CALIBRATING,
PEAK-DETECTING, DIFFERENTIAL
HALL-EFFECT GEAR-TOOTH SENSOR
The ATS612LSG gear-tooth sensor is a peak-detecting device
that uses automatic gain control to provide extremely accurate gear
edge detection down to low operating speeds. Each sensor module
consists of an over-molded package, which holds together a
samarium-cobalt magnet, a pole piece and a differential opencollector Hall IC 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 sensor incorporates a dual-element Hall IC that switches in
response to differential magnetic signals created by ferrous targets.
The sophisticated processing circuitry contains a 5-bit D/A
converter that self-calibrates (normalizes) the internal gain of the
device to minimize the effect of air-gap variations. The patented
peak-detecting filter circuit eliminates magnet and system offsets
and has the ability to discriminate relatively fast changes such as
those caused by tilt, gear wobble, and other eccentricities, yet
provides stable operation to extremely low RPM.
Pin 1: Supply
Pin 2: Output
Pin 3: Capacitor
Pin 4: Ground
This sensor system is ideal for use in gathering speed, position,
and timing information using gear-tooth-based configurations. The
ATS612 is particularly suited to those applications that require
extremely accurate duty cycle control or accurate edge detection
such as in automotive crankshaft applications. The lower vibration
sensitivity also makes this device extremely useful for transmission
speed sensing.
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VCC ..............................…. 24 V
Reverse Supply Voltage, VRCC ................. –16 V
Output OFF Voltage, VOUT ......................... 24 V
Continuous Output Current, IOUT ............ 25 mA
Reverse Output Current, IROUT ............... 50 mA
Package Power Dissipation, PD ...... See Graph
Operating Temperature Range,
TA .............................. –40°°C to +150°°C
Storage Temperature, TS ...................... +170°°C
Maximum Junction Temperature,
TJ .................................................. 165°° C
ATS612G-DS Rev. 0a
FEATURES AND BENEFITS
Fully Optimized Differential Digital Gear-Tooth Sensor
Single-Chip Sensing IC for High Reliability
Digital Output Representing Target Profile
Extremely Low Timing Accuracy Drift with Temperature
Large Operating Air Gaps
Small Mechanical Size
Optimized Magnetic Circuit
Patented Peak-Detecting Filter:
80 µs Typical Power-On Time
<10 RPM Operation (single-tooth target)
Uses Small Value Ceramic Capacitors
Under-Voltage Lockout
Wide Operating Voltage Range
Defined Power-On State
ATS612LSG
DYNAMIC, SELF-CALIBRATING, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT GEAR TOOTH SENSOR
Timing Diagrams
MECHANICAL PROFILE
SIG TOOTH
MAGNETIC PROFILE
SENSOR ELECTRICAL OUTPUT PROFILE
NOTE:
Output polarity is dependent upon sensor orientation and target rotation. See Output Polarity
description on page 9.
Page 2 of 15
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2001, 2003 Allegro MicroSystems, Inc.
ATS612LSG
DYNAMIC, SELF-CALIBRATING, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT GEAR TOOTH SENSOR
ELECTRICAL CHARACTERISTICS over operating voltage and temperature range,
C3 = 0.1 µF to 0.47 µF.
Limits
Characteristic
Supply Voltage
Symbol
VCC
Test Condition
Operating, TJ < 165°C
Min.
Typ.
Max.
Units
3.6
—
24
V
Power-On State
POS
VCC = 0 → 5 V
HIGH
HIGH
HIGH
—
Under-Voltage Lockout
VCC(UV)
VCC = 0 → 5 V
2.5
—
3.6
V
Under-Voltage Hysteresis
VCC(hys)
VCC(UV) – VCC(SD) (see NOTE below)
—
0.2
—
V
VOUT(SAT)
IOUT = 20 mA
—
185
400
mV
VZ
ICC = 18 mA
24
—
—
V
IOUTM
VOUT = 12 V
25
45
55
mA
Output Leakage Current
IOFF
VOUT = 24 V
—
0.2
15
µA
Supply Current
ICC
Output OFF
6.0
8.7
13
mA
Output ON
8.0
10.7
15
mA
Power-On Delay
ton
VCC > 5 V
—
80
500
µs
Output Rise Time
tr
RL = 500 Ω, CL = 10 pF
—
0.2
5.0
µs
Output Fall Time
tf
RL = 500 Ω, CL = 10 pF
—
0.2
5.0
µs
Low Output Voltage
Supply Zener Clamp Voltage
Output Current Limit
NOTES: Typical data is at VCC = 8 V and TA = +25°C and is for design information only.
VCC(SD) = shutdown voltage, VCC = 5 V → 0.
Page 3 of 15
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2001, 2003 Allegro MicroSystems, Inc.
ATS612LSG
DYNAMIC, SELF-CALIBRATING, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT GEAR TOOTH SENSOR
OPERATION over operating voltage and temperature range with reference target
(unless otherwise specified).
Limits
Characteristic
Symbol
Test Condition
Min.
Typ.
Max.
Units
Air Gap Range
AG
Operating within specification,
Target Speed > 20 RPM
0.4
—
2.25
mm
Calibration Cycle
ncal
Output edges before which
Calibration is completed*
1
1
1
Edge
Calibration Mode Disable
ndis
Output falling edges for startup
calibration to be complete
64
64
64
Edges
Relative Timing Accuracy,
Sequential
tθ
Target Speed = 1000 RPM,
0.4 mm ≤ AG ≤ 2 mm
—
±0.3
±0.9
°
Output switching only; may not
meet data sheet specifications
—
—
±50
G
Allowable User Induced
Differential Offset
* Non-uniform magnetic profiles may require additional output pulses before calibration is complete.
Page 4 of 15
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2001, 2003 Allegro MicroSystems, Inc.
ATS612LSG
DYNAMIC, SELF-CALIBRATING, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT GEAR TOOTH SENSOR
REFERENCE TARGET / GEAR INFORMATION
Diameter
120
mm
Thickness
6
mm
Sequential Tooth Width
3
mm
Sequential Valley Width
3
mm
Sequential Valley Depth
3
mm
Signature Tooth Width
9
mm
Material
Page 5 of 15
Low carbon steel
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2001, 2003 Allegro MicroSystems, Inc.
ATS612LSG
DYNAMIC, SELF-CALIBRATING, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT GEAR TOOTH SENSOR
POWER DE-RATING
Due to internal power consumption, the temperature of
the IC (junction temperature, TJ) is higher than the
ambient environment temperature, TA. To ensure that
the device does not operate above the maximum rated
junction temperature use the following calculations:
∆T = PD × RθJA
Then:
If:
∆T = PD × RθJA
then:
Where: PD = VCC × ICC
∴ ∆T=VCC × ICC × RθJA
Where ∆T denotes the temperature rise resulting from
the IC’s power dissipation.
TJ(max) = 165°C
RθJA = 126°C/W
Typical TJ calculation:
PD = VCC × ICC
then the maximum VCC at 150°C is therefore:
VCC(max) = PD(max) / ICC = 119 mW / 15 mA = 7.9 V
This value applies only to the voltage drop across the
ATS612 chip. If a protective series diode or resistor is
used, the effective maximum supply voltage is
increased.
For example, when a standard diode with a 0.7 V drop is
used:
VS(max) = 7.9 V + 0.7 V = 8.6 V
TA = 25 °C
VCC = 5 V
ICC = (ICC(ON)typ + ICC(OFF)typ) / 2 = (10.7 mA +
8.7 mA) / 2 = 9.7 mA
SG Package Power De-Rating Curve
Thermal Resistance = 126°C/Watt, T jmax = 165°C
PD = VCC × ICC = 5 V × 9.7 mA = 48.5 mW
30.0
28.0
Maximum Allowable Power Dissipation Calculation
for ATS612LSG:
Assume:
TA = TA(max) = 150 °C
TJ(max) = 165°C
Icc = (ION(max) + IOFF(max)) / 2
= (15 mA + 13 mA) / 2 = 14 mA
If:
TJ = TA + ∆T
Page 6 of 15
Maximum Supply Voltage [Volts]
∆T = PD × RθJA = 48.5 mW × 165°C/W = 8.0°C
TJ = TA + ∆T = 25°C + 8.0°C = 33.0°C
PD(max) = ∆T(max) / RθJA = 15°C / 126°C/W = 119 mW
If:
TJ = TA + ∆T
For the sensor :
∆T(max) = TJ(max) – TA(max) = 165°C - 150°C = 15°C
26.0
24.0
22.0
20.0
18.0
16.0
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0
20
40
60
80
100
120
140
160
180
Ambient Temperature [°C]
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2001, 2003 Allegro MicroSystems, Inc.
200
ATS612LSG
DYNAMIC, SELF-CALIBRATING, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT GEAR TOOTH SENSOR
DEVICE DESCRIPTION
Assembly Description. The ATS612 gear-tooth sensor
is a Hall IC/magnet configuration that is fully optimized to
provide digital detection of gear tooth edges. This
sensor is packaged in a molded miniature plastic body
that has been optimized for size, ease of assembly, and
manufacturability. High operating temperature materials
are used in all aspects of construction.
comparator. In this manner, the thresholds are adapted
and referenced to individual signal peaks and valleys,
providing immunity to zero line variation from 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 for small value filter
capacitors.
The use of this sensor is simple. After proper power is
applied to the component the sensor is then 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 module
contains a single-chip differential Hall effect sensor IC, a
Samarium Cobalt magnet, and a flat ferrous pole piece
(Figure 2). The Hall IC consists of 2 Hall elements
(spaced 2.2 mm apart) located so as to measure the
magnetic gradient created by the passing of a ferrous
object. The two elements measure the magnetic
gradient and convert it to an analog voltage that is then
processed in order to provide a digital output signal.
Magnetic Circuit
Figure 2
Internal Electronics. The processing circuit uses a
patented peak detection scheme to eliminate magnet
and system offsets. This technique allows dynamic
coupling and filtering of offsets without the power-up and
settling time disadvantages of classical high-pass
filtering schemes. The peak signal of every tooth and
valley is detected by the filter and is used to provide an
instant reference for the operate and release point
Page 7 of 15
The ATS612 also includes self-calibration circuitry that is
engaged at power on. The signal amplitude is measured
and the device gain is normalized. In this manner,
switch-point drift versus air gap is minimized and
excellent timing accuracy can be achieved. The AGC
(Automatic Gain Control) circuitry, in conjunction with a
unique hysteresis circuit, also eliminates the effect of
gear edge overshoot as well as increases the immunity
to false switching caused by gear tooth anomalies at
close air gap. The AGC circuit sets the gain of the
device after power on. Up to 0.25 mm air gap change
can occur after calibration is complete without significant
performance impact.
Superior Performance. The ATS612 peak-detecting
differential gear-tooth sensor module has several
advantages over conventional Hall-effect gear-tooth
sensors. The signal-processing techniques used in the
ATS612 solve the catastrophic issues that affect the
functionality of conventional digital gear-tooth sensors.
• Temperature drift. Changes in temperature do not
greatly affect this device due to the stable amplifier
design and the offset rejection circuitry.
• Timing accuracy variation due to air gap. The
accuracy variation caused by air gap changes is
minimized by the self-calibration circuitry. A 2x-to-3x
improvement can be seen.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2001, 2003 Allegro MicroSystems, Inc.
ATS612LSG
DYNAMIC, SELF-CALIBRATING, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT GEAR TOOTH SENSOR
•
•
•
•
•
•
•
Dual edge detection. Because this device switches
from 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 peak detector circuitry
references the switch point from the peak and is
immune to this failure mode. There may be a timing
accuracy shift caused by this condition.
Large operating air gaps. Large operating air gaps
are achievable with this device due to the sensitive
switch points after start up. (dependent on target
dimensions, material, and speed).
Immunity to magnetic overshoot. The air gapindependent hysteresis minimizes the impact of
overshoot on the switching of device output.
Response to surface defects in the target. The
gain-adjust circuitry reduces the effect of minor gear
anomalies that would normally cause false
switching.
Immunity to vibration and backlash. The gainadjust 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 baseline variations
caused by gear run out.
Differential vs. Single-Element Sensing. The
differential Hall-effect configuration is superior in most
applications to the classical single-element gear-tooth
sensor. As shown in the flux maps on this page, 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
<100 G) that is superimposed on a large back-biased
field, often 1500 G to 3500 G. For most gear/target
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 cancels the
effects of the back-biased field and avoids many of the
issues presented by the single Hall element.
NOTE: 10 G = 1 mT, exactly.
Page 8 of 15
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2001, 2003 Allegro MicroSystems, Inc.
ATS612LSG
DYNAMIC, SELF-CALIBRATING, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT GEAR TOOTH SENSOR
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 on because the filter circuit needs to hold
the circuit zero value even though the circuit may power
on 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,
high-pass 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.
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 of the 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 onehalf the peak-to-peak signal.
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 up to 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 unit will switch from
HIGH to LOW as the leading edge of the tooth passes
the unit in the direction indicated in figure 3 which means
that in this configuration, the output voltage will be high
when the unit is facing a tooth. If rotation is in the
opposite direction, the output polarity will be opposite as
well, with the unit switching LOW to HIGH as the leading
edge passes the unit.
Figure 3
NOTE – “Baseline” refers to the zero-gauss differential
field where each Hall-effect element is subject to the
same magnetic field strength.
Power-On Operation. The device will power on in the
OFF state (output high) irrespective of the magnetic field
condition. The power-up time of the circuit is no greater
than 500 µs. The circuit is then ready to accurately
detect the first target edge that results in a HIGH-toLOW transition.
Under-Voltage Lockout. When the supply voltage is
below the minimum operating voltage (VCC(UV)), the
Page 9 of 15
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2001, 2003 Allegro MicroSystems, Inc.
ATS612LSG
DYNAMIC, SELF-CALIBRATING, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT GEAR TOOTH SENSOR
TYPICAL ELECTRICAL CHARACTERISTICS
ICC
ICC
13
Output On
9
7
Output Off
VCC
= 8V
Output On
11
9
Output Off
7
TA =
25 oC
5
5
-40
0
40
80
120
160
2
200
6
o
14
10
18
22
SUPPLY VOLTAGE IN VOLTS
AMBIENT TEMPERATURE IN C
VOUT(SAT)
250
OUTPUT SATURATION VOLTAGE IN mV
SUPPLY CURRENT IN mA
11
SUPPLY CURRENT IN mAA
13
IOUT =
20mA
225
200
175
150
-40
0
40
80
120
160
o
AMBIENT TEMPERATURE IN C
Page 10 of 15
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2001, 2003 Allegro MicroSystems, Inc.
26
ATS612LSG
DYNAMIC, SELF-CALIBRATING, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT GEAR TOOTH SENSOR
TYPICAL OPERATING CHARACTERISTICS
(Relative Accuracy data presented has been normalized to 1.5 mm air gap at 1000 RPM)
Rising signature tooth edge 1000 RPM
Falling signature tooth edge 1000 RPM
0.75
-40oC
25oC
150oC
1
RELATIVE ACCURACY IN DEGREES
RELATIVE ACCURACY IN DEGREES
1.5
0.5
0
-0.5
-1
-1.5
o
-40 C
o
25 C
o
150 C
0.5
0.25
0
-0.25
-0.5
-0.75
0
0.5
1
1.5
2
2.5
3
0
0.5
AIR GAP IN MILLIMETERS
Rising signature tooth edge 10 RPM
1.5
2
2.5
3
Falling signature tooth edge 10 RPM
1.5
0.75
-40oC
25oC
150oC
1
-40 oC
RELATIVE ACCURACY IN DEGREES
RELATIVE ACCURACY IN DEGREES
1
AIR GAP IN MILLIMETERS
0.5
0
-0.5
-1
25 oC
0.5
150 oC
0.25
0
-0.25
-0.5
-0.75
-1.5
0
0.5
1
1.5
2
AIR GAP IN MILLIMETERS
Page 11 of 15
2.5
3
0
0.5
1
1.5
2
2.5
AIR GAP IN MILLIMETERS
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2001, 2003 Allegro MicroSystems, Inc.
3
ATS612LSG
DYNAMIC, SELF-CALIBRATING, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT GEAR TOOTH SENSOR
TYPICAL OPERATING CHARACTERISTICS
Rising sequential tooth edge 1000 RPM
Falling sequential tooth edge 1000 RPM
0.75
0.75
o
0.5
RELATIVE ACCURACY IN DEGREES
RELATIVE ACCURACY IN DEGREES
o
-40 C
o
25 C
o
150 C
0.25
0
-0.25
-0.5
-40 C
o
25 C
o
150 C
0.5
0.25
0
-0.25
-0.5
-0.75
-0.75
0
0.5
1
1.5
2
2.5
0
3
0.5
AIR GAP IN MILLIMETERS
Rising sequential tooth edge 10 RPM
2
2.5
3
2.5
3
0.75
-40 oC
-40 oC
25oC
0.5
1.5
Falling sequential tooth edge 10 RPM
RELATIVE ACCURACY IN DEGREES
RELATIVE ACCURACY IN DEGREES
0.75
1
AIR GAP IN MILLIMETERS
150 oC
0.25
0
-0.25
-0.5
-0.75
25 oC
0.5
150 oC
0.25
0
-0.25
-0.5
-0.75
0
0.5
1
1.5
2
AIR GAP IN MILLIMETERS
Page 12 of 15
2.5
3
0
0.5
1
1.5
2
AIR GAP IN MILLIMETERS
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2001, 2003 Allegro MicroSystems, Inc.
ATS612LSG
DYNAMIC, SELF-CALIBRATING, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT GEAR TOOTH SENSOR
MECHANICAL INFORMATION
1
2
Component
Material
Function
Value
Sensor Package Material
Thermoset Epoxy
Max. Temperature
170°C
Leads
Copper, 0.016” dia, 0.050” spacing
Lead Coating
Solder, Tin / Lead 90/10
1
2
Temperature excursions of up to 225°C for 2 minutes or less are permitted.
Industry accepted soldering techniques are acceptable for this module as long as the indicated maximum temperatures for each component are not
exceeded. Please see the Allegro website (http://www.allegromicro.com/techpub2/an/an26009.pdf) for soldering profile.
ELECTROMAGNETIC CAPABILITY (EMC) PERFORMANCE
Please contact Allegro MicroSystems for EMC performance.
Page 13 of 15
Test Name
Reference Specification
ESD – Human Body Model
ESD – Machine Model
Conducted Transients
AEC-Q100-002
AEC-Q100-003
ISO 7637-1
Direct RF Injection
ISO 11452-7
Bulk Current Injection
TEM Cell
ISO 11452-4
ISO 11452-3
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2001, 2003 Allegro MicroSystems, Inc.
ATS612LSG
DYNAMIC, SELF-CALIBRATING, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT GEAR TOOTH SENSOR
PACKAGE DRAWING
For Reference Only
NOTE: Metallic protrusion may be present, electrically connected to substrate and pin 4 (ground).
Page 14 of 15
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2001, 2003 Allegro MicroSystems, Inc.
ATS612LSG
DYNAMIC, SELF-CALIBRATING, PEAK-DETECTING,
DIFFERENTIAL HALL-EFFECT GEAR TOOTH SENSOR
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; 5,719,130; 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 design 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 applications, 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 which may result from its use.
Page 15 of 15
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2001, 2003 Allegro MicroSystems, Inc.