Allegro ATS651LSH Two-wire self-calibrating differential speed and direction sensor with vibration immunity Datasheet

ATS651LSH
Two-Wire Self-Calibrating Differential
Speed and Direction Sensor with Vibration Immunity
Package SH
12
34
1. VCC
2. TESTA pin, Channel A
3. TESTB pin, Channel B
4. GND
ABSOLUTE MAXIMUM RATINGS
Supply Voltage*, VCC ......................................... 28 V
Reverse-Supply Voltage, VRCC ........................ –18 V
Reverse-Output Voltage, VROUT...................... –0.5 V
Temperatures
Operating Ambient, TA................. –40ºC to 150ºC
Junction, TJ(MAX) .......................................165ºC
Storage, TS ................................. –65ºC to 170ºC
*Refer to Power Derating section
The ATS651LSH is a mechatronics component with an integrated Hall-effect
sensor and magnet, providing an easy-to-use solution for speed and direction sensing applications. The solid thermoset molded plastic package contains a samarium
cobalt magnet and a Hall-effect IC optimized to the magnetic circuit. This sensor
module has been designed specifically for high reliability in the harsh automotive environment. The IC employs patented algorithms for the special operational
requirements of transmission applications.
This two-wire device communicates the speed and direction of a ferrous target
via a pulse width modulation (PWM) output protocol. The innovative dual differential detector scheme uses three Hall elements and two separate signal processing
channels. This provides greater reliability than conventional designs. Because only
one of the channels controls switching, the same edge of each tooth is used for
determining output signals, in both forward and reverse target rotation, with direction information available on the first magnetic edge after a direction change.
The ATS651LSH is particularly adept at handling vibration without sacrificing maximum air gap capability or creating an erroneous “direction” pulse. Even
the higher angular vibration caused by engine cranking is completely rejected by
the device. The advanced vibration detection algorithms systematically calibrate
the sensor on the true rotation signals from the first three and a half teeth, not on
vibration, thus always guaranteeing an accurate signal in running mode.
Patented running mode algorithms also protect against air gap changes, whether
or not the target is in motion. Advanced signal processing and innovative algorithms make the ATS651LSH an ideal solution for a wide range of speed and
direction sensing needs.
The device package is lead (Pb) free, with 100% matte tin plated leadframe.
Features and Benefits
•
•
•
•
•
•
•
•
•
•
•
•
Rotational direction detection
Fully optimized digital differential gear-tooth sensor
Single-chip sensing IC for high reliability
Small mechanical size (8 mm diameter × 5.5 mm vertical, flat-to-flat)
Internal current regulator for 2-wire operation
Automatic Gain Control (AGC) and reference adjust circuit
3-bit factory trimmed for tight pulse width accuracy
True zero-speed operation
Wide operating voltage range
Undervoltage lockout
Defined power-on state
ESD and reverse polarity protection
Use the following complete part numbers when ordering:
Part Number
Packing*
ATS651LSHTN-T
13-in. reel, 800 pieces/reel
*Contact Allegro for additional packing options.
Some restrictions may apply to certain types of sales.
Contact Allegro for details.
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
ATS651LSH
Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity
Functional Block Diagram
V+
VCC
Voltage
Regulator
Hall
Element 1
PThresh
PDAC
Channel A
0.01μF
CBYPASS
Offset
Adjust
Hall
Amp
Reference
Generator
and
Updates
AGC
Hall
Element 2
Threshold
Logic
NDAC
NThresh
Speed
and
Direction
Logic
PThresh
PDAC
Channel B
Hall
Element 3
Offset
Adjust
Hall
Amp
Reference
Generator
and
Updates
AGC
Current
Output
Adjust
Threshold
Logic
NDAC
NThresh
GND
TESTA
TESTB
(Recommended)
(Recommended)
Typical Application Diagram
ECU
ICC(HIGH)/ICC(LOW)
1
2
ATS651
3
0.01 μF
CBYPASS
4
Note: Pins 2 and 3 may be connected to pin 4.
However, ICC is increased in that configuration.
100 Ω
RSENSE
CSENSE
2
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
ATS651LSH
Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity
Device Characteristics Tables
ELECTRICAL CHARACTERISTICS Valid for –40°C ≤ TA ≤ 150°C, TJ ≤ 165°C, unless otherwise noted
Characteristics
Supply Voltage
Symbol
VCC
Undervoltage Lockout
Reverse Supply Current
VCC(UV)
IRCC
Supply Zener Clamp Voltage
VZ
Supply Zener Resistance
RZ
Test Conditions
Min.
Typ.
4.3
–
VCC = –18 V
ICC(Low)max + 3 mA
Running, TJ ≤ 165°C
VCC = 5 → 0 V
Max.
Units
–
24
V
–
4.3
V
–
–
–10
mA
28
–
40
V
–
20
–
Ω
2
16
–
mA/μs
Output Current Slew Rate
SRI
I(High) → I(Low) , I(Low) → I(High)
RSENSE = 100 Ω, CSENSE = 10 pF, 10 to 90% points
Power-On State
POS
ION state
–
ICC(Low)
–
mA
Power-On Time1
tPO
Gear speed < 100 rpm
–
–
1
ms
ICC(Low)
Low-current state
4
7
9
mA
ICC(High)
High-current state
12
14.5
17
mA
ΔICC
ICC(High) - ICC(Low); difference between high-current state level
and low-current state level
5.3
–
–
mA
Direction Information2
NDir
First output transition
–
–
8
Edge
Speed Information2
NSpd
First output transition
–
–
8
Edge
NCD
Running mode direction change
–
–
1
Edge
ECAL
Over four edges
–
–
±0.3
mm
As shipped
–
±60
–
G
Supply Current
Supply Current Difference
CALIBRATION
Direction Change
Detection3
Signal Variation4
(At calibration)
DAC CHARACTERISTICS
Dynamic Offset Cancellation5
1Power-On
Time is the time required to complete the internal automatic offset adjust; the DACs are then ready for peak acquisition.
count is based on mechanical edges. First output edge is available on or before NDir or NSpd edges.
3Edge count is based on mechanical edges. On the N
CD edge, direction and speed information is valid.
4If the peak-to-peak amplitude of the signal varies more than the specified amount during the direction verification process, then additional edges may
be required for calibration.
5The device will compensate for magnetic and installation offsets up to ±60 gauss. Offsets greater than ±60 gauss may cause inaccuracies in the
output.
2Edge
OPERATING CHARACTERISTICS Using Reference Target 60-0 and valid over operating temperature range
Characteristics
Operational Air Gap Range*
Operating Signal Range
Symbol
Min.
Typ.
Max.
Units
AGOP
Within specification
Test Conditions
0.5
–
2.8
mm
Sig
Within specification
30
–
1200
G
*Operational Air
Gap Range is dependent on the available differential magnetic field. The available field is dependent on target geometry and material,
and should be independently characterized. The field available from the Reference Target is given in the Reference Target Parameters section of this
datasheet.
Continued on the next page...
3
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
ATS651LSH
Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity
Device Characteristics Tables (Continued)
SWITCHING CHARACTERISTICS Valid for –40°C ≤ TA ≤ 150°C, TJ ≤ 165°C, unless otherwise noted
Characteristics
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Operate Point
BOP
% of peak-to-peak referenced from PDAC to NDAC,
AGOP < AGOP(max)
–
58
–
%
Release Point
BRP
% of peak-to-peak referenced from PDAC to NDAC,
AGOP < AGOP(max)
–
42
–
%
–
–
±1.75
mm
Instantaneous air gap change (<500 Hz)
–
–
±0.4
mm
Air gap change between edges @ >8 kHz
–
–
Axial/Radial Runout1
(Multiple teeth)
ROA/R
Sudden Air Gap
(Single tooth)
ΔAGSAG
ΔAGIR+
Incremental Air Gap
(Consecutive edges)
Vibration Immunity2
(Running)
Maximum Operating Frequency3
±0.1
mm
±0.15
mm
Air gap change between edges @ <4 kHz
–
–
±0.2
mm
ROTVIBS
Rotation allowed due to vibration with temperature change
less than 10°C
–
–
±0.75
(°)
ROTVIBR
Rotation allowed due to vibration with temperature change
less than 10°C
–
–
±0.35
(°)
ffwd
Forward target rotation (pin 4 to pin 1), tLD = 38 μs
12
–
–
kHz
frev
Reverse target rotation (pin 1 to pin 4), tLD = 38 μs
6
–
–
kHz
ΔAGIRVibration Immunity
(At power-on)
Air gap change between edges @ 8-4 kHz
1Inclusive
of all Sudden Air Gap and Incremental Air Gap changes during operation.
may output one reverse pulse at the start of vibration.
3Maximum Operating Frequency may be increased if the customer can resolve Minimum Low-State Duration levels down to the specified value.
2Device
Continued on the next page...
ATS651LSH Switchpoints
Sensed Edgea
Channel A Differential Magnetic
Flux Density, B (G)
Reverse
Forward
Tooth
Valley
B+
BOP(fwd)b
BOP(rev)b
BRP(rev)
BOP %
BRP(fwd)
B–
100 %
BRP %
t
aSensed Edge: leading (rising) edge in forward rotation, trailing (falling) edge in reverse rotation
bB
triggers the output pulse during forward rotation, and B
triggers the output pulse during reverse rotation
OP(fwd)
OP(rev)
4
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
ATS651LSH
Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity
Device Characteristics Tables (Continued)
Protocol Pulse Characteristics Valid for –40°C ≤ TA ≤ 150°C (TJ ≤ 165°C), unless otherwise noted
Characteristics
Symbol
Minimum Low-State Duration*
tLD
Test Conditions
Falling edge to subsequent rising edge.
Min.
Typ.
Max.
Units
10
–
–
μs
Pulse Width Forward Rotation
tW(fwd)
38
45
52
μs
Pulse Width Reverse Rotation
tW(rev)
76
90
104
μs
Protocol Pulse Width Tolerance
EPPW
–15
–
15
%
Reference Target
*Maximum Operating Frequency may be increased if the application controller can resolve Minimum Low-State Duration levels down to the specified
value.
5
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
ATS651LSH
Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity
Reference Target Parameters
REFERENCE TARGET CHARACTERISTICS 60-0 (60 Tooth Target)
Characteristics
Outside Diameter
Symbol
Test Conditions
Outside diameter of target
Do
Typ.
Units
120
mm
Face Width
F
Breadth of tooth, with respect
to sensor
6
mm
Circular Tooth Length
t
Length of tooth, with respect
to sensor; measured at Do
3
mm
Circular Valley Length
tv
Length of valley, with respect
to sensor; measured at Do
3
mm
Tooth Whole Depth
ht
3
mm
–
–
Material
Low Carbon Steel
Symbol Key
t
Do
ht
F
tv
Air Gap
Branded Face of Sensor
Reference Gear Magnetic Gradient Amplitude
with Reference to Air Gap
1800
Peak-to-Peak Differential
Magnetic Flux Density (G)
1600
1400
1200
1000
800
600
Branded Face
of Sensor
400
Reference Target
60-0
200
0
0.5
1
AG (mm)
1.5
2
2.5
Reference Gear Magnetic Profile
Two Tooth-to-Valley Transitions
Differential Magnetic Flux Density (G)
700
600
500
400
300
AG (mm)
0.50
0.75
1.00
1.25
1.50
1.75
2.00
200
100
0
-100
-200
-300
-400
2.00 mm AG
-500
-600
0.50 mm AG
-700
0
1
2
3
4
5
6
7
8
9
10
11
12
Gear Rotation (°)
6
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
ATS651LSH
Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity
Characteristic Data
Supply Current (High) vs. Ambient Temperature
17
ICC(High) (mA)
16
4V
15
12V
14
20V
24V
13
12
-40°
25°
85°
150°
TA (°C)
Supply Current (Low) vs. Ambient Temperature
ICC(Low) (mA)
9
8
4V
7
12V
6
20V
24V
5
4
-40°
25°
85°
150°
TA (°C)
7
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
ATS651LSH
Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity
Characteristic Data (Continued)
Pulse Width (Right) vs. Ambient Temperature
52
tW(R) (µs)
50
48
46
44
42
40
38
-40°
25°
150°
TA (°C)
Pulse Width (Left) vs. Ambient Temperature
104
tW(L) (µs)
100
96
92
88
84
80
76
-40°
25°
150°
TA (°C)
SENSOR EVALUATION: EMC
Characterization Only*
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
*Please contact Allegro MicroSystems for EMC performance.
8
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
ATS651LSH
Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity
THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information
Characteristic
Symbol
Test Conditions
RθJA
Package Thermal Resistance
Min.
Typ.
Max Units
1-layer PCB with copper limited to solder pads
126
–
–
ºC/W
2-layer PCB with 3.57 in.2 of copper area each side
connected by thermal vias
84
–
–
ºC/W
Maximum Allowable VCC (V)
Power Derating Curve
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
VCC(max)
(RθJA = 84 ºC/W)
(RθJA = 126 ºC/W)
VCC(min)
20
40
60
80
100
120
140
160
180
Power Dissipation, PD (m W)
Maximum Power Dissipation, PD(max)
1900
1800
1700
1600
1500
1400
1300
1200
1100
1000
900
800
700
600
500
400
300
200
100
0
R
θJ
A
=
R
θJ
20
40
A
60
=1
26
ºC
84
ºC
/W
/W
80
100
120
Temperature (°C)
140
160
180
9
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
ATS651LSH
Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity
Applications Information
Data Protocol Description
When a ferrous target passes in front of the sensor (the branded
face of the sensor case), each tooth of the target generates a pulse
at the output pin of the sensor. Each pulse provides target speed
and direction data: speed is provided by the pulse rate, while
direction of target rotation is provided by the pulse width.
The ATS651 can sense target movement in both the forward and
reverse directions. The maximum allowable target rotational
speed is limited by the width of the output pulse and the shortest
Low-State Duration the system controller can resolve.
Forward Rotation (See panel a in figure 1) When the target is
rotating such that a tooth near the sensor passes from pin 4 to
pin 1, this is referred to as forward rotation. This is diagrammed
below. Forward rotation is indicated on the output pin by a 45 μs
pulse width.
Reverse Rotation (See panel b in figure 1) When the target
is rotating such that target teeth pass from pin 1 to pin 4, it is
referred to as reverse rotation. Reverse rotation is indicated on
the output pin by a 90 μs pulse width, twice as long as the pulse
generated by forward rotation.
Timing. As shown in figure 2, the pulse appears at the output pin
slightly before the sensed mechanical edge traverses the sensor.
For targets in forward rotation, this shift, Δfwd, results in the
pulse corresponding to the valley with the sensed mechanical
edge, and for targets in reverse rotation, the shift, Δrev, results in
the pulse corresponding to the tooth with the sensed edge. The
sensed mechanical edge that stimulates output pulses is kept the
same for both forward and reverse rotation by using only channel
A for switching.
The overall range between the forward and reverse pulse occurrences is determined by the 1.5 mm spacing between the Hall
elements of the corresponding differential channel. In either
direction, the pulses appear close to the sensed mechanical edge.
The length of the target features, however, can slightly bias the
occurrence of the pulses.
(a) Forward Rotation
Pin 4
Pin 1
Reverse
Branded Face
of Sensor
Rotating Target
Forward
Valley
Δfwd
Output
(Forward
Rotation)
(b) Reverse Rotation
Pin 4
Rotating Target
Figure 1. Target rotation
Pin 1
Branded Face
of Sensor
Tooth
Δrev
45 μs
90 μs
Output
(Reverse
Rotation)
Figure 2. Output pulse timing
10
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
ATS651LSH
Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity
Power Derating
The device must be operated below the maximum junction
temperature of the device, TJ(max). Under certain combinations of
peak conditions, reliable operation may require derating supplied power or improving the heat dissipation properties of the
application. This section presents a procedure for correlating
factors affecting operating TJ. (Thermal data is also available on
the Allegro MicroSystems Web site.)
Example: Reliability for VCC at TA = 150°C, package SH, using
the PCB with least exposed copper.
The Package Thermal Resistance, RθJA, is a figure of merit summarizing the ability of the application and the device to dissipate
heat from the junction (die), through all paths to the ambient air.
Its primary component is the Effective Thermal Conductivity,
K, of the printed circuit board, including adjacent devices and
traces. Radiation from the die through the device case, RθJC, is
relatively small component of RθJA. Ambient air temperature,
TA, and air motion are significant external factors, damped by
overmolding.
Calculate the maximum allowable power level, PD(max). First,
invert equation 3:
The effect of varying power levels (Power Dissipation, PD), can
be estimated. The following formulas represent the fundamental
relationships used to estimate TJ, at PD.
PD = VIN × IIN
(1)
ΔT = PD × RθJA
(2)
TJ = TA + ΔT
(3)
For example, given common conditions such as: TA= 25°C,
VCC = 5 V, ICC = 14 mA, and RθJA = 126 °C/W, then:
PD = VCC × ICC = 12 V × 4.0 mA = 70.0 mW
Observe the worst-case ratings for the device, specifically:
RθJA = 126°C/W, TJ(max) = 165°C, VCC(max) = 28 V, and
ICC(max) = 16.8 mA.
ΔTmax = TJ(max) – TA = 165 °C – 150 °C = 15 °C
This provides the allowable increase to TJ resulting from internal
power dissipation. Then, invert equation 2:
PD(max) = ΔTmax ÷ RθJA = 15°C ÷ 126 °C/W = 119 mW
Finally, invert equation 1 with respect to voltage:
VCC(est) = PD(max) ÷ ICC(max) = 119 mW ÷ 16.8 mA = 7.1 V
The result indicates that, at TA, the application and device can
dissipate adequate amounts of heat at voltages ≤VCC(est).
Compare VCC(est) to VCC(max). If VCC(est) ≤ VCC(max), then reliable operation between VCC(est) and VCC(max) requires enhanced
RθJA. If VCC(est) ≥ VCC(max), then operation between VCC(est) and
VCC(max) is reliable under these conditions.
ΔT = PD × RθJA = 70.0 mW × 126 °C/W = 8.8°C
This value applies only to the voltage drop across the
ATS651LSH chip. If a protective series diode or resistor is used,
the effective maximum supply voltage is increased.
TJ = TA + ΔT = 25°C + 8.8°C = 23.8°C
For example, when a standard diode with a 0.7 V drop is used:
A worst-case estimate, PD(max), represents the maximum allowable power level (VCC(max), ICC(max)), without exceeding TJ(max),
at a selected RθJA and TA.
VS(max) = 7.1 V + 0.7 V = 7.8 V
11
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
ATS651LSH
Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity
Package SH, 4-pin SIP
5.5 .217
E 1.50 .0591
C
E 1.50 .0591
B
8.0
.315
E1
E 0.23 .009
5.8
.228
2.9
4.0
5.0
.157
E3
E2
.114
1.7
0.38 .015
A
.067
.244
1
2
3
4
1.08 .043
1 .039
20.95 .825
13.05 .514
0.6 .024
A
D
0.6 .024
1.27
Preliminary dimensions, for reference only
Untoleranced dimensions are nominal.
Dimensions in millimeters
U.S. Customary dimensions (in.) in brackets, for reference only
Dimensions exclusive of mold flash, burrs, and dambar protrusions
Exact case and lead configuration at supplier discretion within limits shown
.050
A
Dambar removal protrusion (16X)
B
Metallic protrusion, electrically connected to pin 4 and substrate (both sides)
C
Active Area Depth, 0.43 [.017]
D
Thermoplastic Molded Lead Bar for alignment during shipment
E
Hall elements (E1,E2, and E3), not to scale; controlling dimension inches
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 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 infringement of patents or other rights of third parties which may result from its use.
Copyright © 2005 Allegro MicroSystems, Inc.
12
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com