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ATS651LSH
Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity
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.
Package SH
12
34
1. VCC 2. TESTA pin, Channel A 3. TESTB pin, Channel B 4. GND
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 x 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 Part Number ATS651LSHTN-T Packing* 13-in. reel, 800 pieces/reel
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................. -40C to 150C Junction, TJ(MAX) .......................................165C Storage, TS ................................. -65C to 170C
*Refer to Power Derating section
Use the following complete part numbers when ordering:
*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 Channel A 0.01F CBYPASS Hall Amp Hall Element 2 NDAC Offset Adjust AGC PDAC
PThresh
Reference Generator and Updates NThresh PThresh
Threshold Logic
Channel B Hall Element 3 Hall Amp Offset Adjust AGC
PDAC Reference Generator and Updates NDAC NThresh Threshold Logic
Speed and Direction Logic
Current Output Adjust
GND (Recommended) (Recommended)
TESTA
TESTB
Typical Application Diagram
ECU ICC(HIGH)/ICC(LOW)
1
2
ATS651
3
0.01 F CBYPASS
4
Note: Pins 2 and 3 may be connected to pin 4. However, ICC is increased in that configuration.
100 RSENSE CSENSE
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
2
ATS651LSH
Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity
Device Characteristics Tables
ELECTRICAL CHARACTERISTICS Valid for -40C TA 150C, TJ 165C, unless otherwise noted
Characteristics Supply Voltage Undervoltage Lockout Reverse Supply Current Supply Zener Clamp Voltage Supply Zener Resistance Output Current Slew Rate Power-On State Power-On Time1 Supply Current Supply Current Difference Symbol VCC VCC(UV) IRCC VZ RZ SRI POS tPO ICC(Low) ICC(High) ICC I(High) I(Low) , I(Low) I(High) RSENSE = 100 , CSENSE = 10 pF, 10 to 90% points ION state Gear speed < 100 rpm Low-current state High-current state ICC(High) - ICC(Low); difference between high-current state level and low-current state level First output transition First output transition Running mode direction change Over four edges Running, TJ 165C VCC = 5 0 V VCC = -18 V ICC(Low)max + 3 mA Test Conditions Min. 4.3 - - 28 - 2 - - 4 12 5.3 Typ. - - - - 20 16 ICC(Low) - 7 14.5 - Max. 24 4.3 -10 40 - - - 1 9 17 - Units V V mA V mA/s mA ms mA mA mA
CALIBRATION
Direction Information2 Speed Information2 Direction Change Signal Variation4 (At calibration) Detection3 NDir NSpd NCD ECAL - - - - - - - - 8 8 1 0.3 Edge Edge Edge mm
DAC CHARACTERISTICS
Dynamic Offset Cancellation5
1Power-On 2Edge
As shipped
-
60
-
G
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.
OPERATING CHARACTERISTICS Using Reference Target 60-0 and valid over operating temperature range
Characteristics Operational Air Gap Range* Operating Signal Range
*Operational Air
Symbol AGOP Sig Within specification Within specification
Test Conditions
Min. 0.5 30
Typ. - -
Max. 2.8 1200
Units mm G
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...
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
3
651LSH-DS, Rev. 3
ATS651LSH
Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity
Device Characteristics Tables (Continued)
SWITCHING CHARACTERISTICS Valid for -40C TA 150C, TJ 165C, unless otherwise noted
Characteristics Operate Point Release Point Axial/Radial Runout1 (Multiple teeth) Sudden Air Gap (Single tooth) Incremental Air Gap (Consecutive edges) Vibration Immunity (At power-on) Vibration Immunity2 (Running) Maximum Operating Frequency3
1Inclusive 2Device
Symbol BOP BRP ROA/R AGSAG AGIR+ AGIRROTVIBS ROTVIBR ffwd frev
Test Conditions % of peak-to-peak referenced from PDAC to NDAC, AGOP < AGOP(max) % of peak-to-peak referenced from PDAC to NDAC, AGOP < AGOP(max)
Min. - - -
Typ. 58 42 - - - - - - - -
Max. - - 1.75 0.4 0.1 0.15 0.2 0.75 0.35 - -
Units % % mm mm mm mm mm () () kHz kHz
Instantaneous air gap change (<500 Hz) Air gap change between edges @ >8 kHz Air gap change between edges @ 8-4 kHz Air gap change between edges @ <4 kHz Rotation allowed due to vibration with temperature change less than 10C Rotation allowed due to vibration with temperature change less than 10C Forward target rotation (pin 4 to pin 1), tLD = 38 s Reverse target rotation (pin 1 to pin 4), tLD = 38 s
- - - - - 12 6
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.
Continued on the next page...
ATS651LSH Switchpoints
Sensed Edgea Reverse Channel A Differential Magnetic Flux Density, B (G) B+ Tooth Valley
Forward
BOP(fwd)b
BOP(rev)b BRP(rev) BOP % BRP(fwd) BRP % 100 %
B-
OP(fwd) OP(rev)
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
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
4
ATS651LSH
Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity
Device Characteristics Tables (Continued)
Protocol Pulse Characteristics Valid for -40C TA 150C (TJ 165C), unless otherwise noted
Characteristics Minimum Low-State Duration* Pulse Width Forward Rotation Pulse Width Reverse Rotation Protocol Pulse Width Tolerance Symbol tLD tW(fwd) tW(rev) EPPW Reference Target Test Conditions Falling edge to subsequent rising edge. Min. 10 38 76 -15 Typ. - 45 90 - Max. - 52 104 15 Units s s s %
*Maximum Operating Frequency may be increased if the application controller can resolve Minimum Low-State Duration levels down to the specified value.
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
5
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 Face Width Circular Tooth Length Circular Valley Length Tooth Whole Depth Material Symbol Do F t tv ht Low Carbon Steel Test Conditions Outside diameter of target Breadth of tooth, with respect to sensor Length of tooth, with respect to sensor; measured at Do Length of valley, with respect to sensor; measured at Do Typ. 120 6 3 3 3 - Units mm mm mm mm mm -
Air Gap Branded Face of Sensor tv
Symbol Key
t Do F ht
Reference Gear Magnetic Gradient Amplitude with Reference to Air Gap
1800 1600
Peak-to-Peak Differential Magnetic Flux Density (G)
1400 1200 1000 800 600 400 200 0 0.5 1 AG (mm) 1.5 2 2.5
Branded Face of Sensor
Reference Target 60-0
Reference Gear Magnetic Profile Two Tooth-to-Valley Transitions
700
Differential Magnetic Flux Density (G)
600 500 400 300 200 100 0 -100 -200 -300 -400 -500 -600 -700 0 1 2 3 4 5 6 7 8 9 10 11 12 Gear Rotation () 2.00 mm AG 0.50 mm AG
AG (mm) 0.50 0.75 1.00 1.25 1.50 1.75 2.00
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
6
ATS651LSH
Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity
Characteristic Data
Supply Current (High) vs. Ambient Temperature
17 16
ICC(High) (mA)
4V 15 14 13 12 -40 25 TA (C) 85 150 12V 20V 24V
Supply Current (Low) vs. Ambient Temperature
9
ICC(Low) (mA)
8 4V 7 6 5 4 -40 25
TA (C)
12V 20V 24V
85
150
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
7
ATS651LSH
Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity
Characteristic Data (Continued)
Pulse Width (Right) vs. Ambient Temperature
52 50 48 46 44 42 40 38 -40 25 TA (C) 150
tW(R) (s)
Pulse Width (Left) vs. Ambient Temperature
104 100 96 92 88 84 80 76 -40 25 150
tW(L) (s)
TA (C)
SENSOR EVALUATION: EMC
Characterization Only*
Test Name
ESD - Human Body Model ESD - Machine Model Conducted Transients Direct RF Injection Bulk Current Injection TEM Cell
Reference Specification
AEC-Q100-002 AEC-Q100-003 ISO 7637-1 ISO 11452-7 ISO 11452-4 ISO 11452-3
*Please contact Allegro MicroSystems for EMC performance.
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
8
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 Package Thermal Resistance Symbol RJA Test Conditions 1-layer PCB with copper limited to solder pads 2-layer PCB with 3.57 in.2 of copper area each side connected by thermal vias Min. 126 84 Typ. - - Max Units - - C/W C/W
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 20 40 60
VCC(max)
Maximum Allowable VCC (V)
(RJA = 84 C/W) (RJA = 126 C/W)
VCC(min)
80
100
120
140
160
180
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 20 40
Power Dissipation, PD (m W)
R
J
A
=
R
J
84
A
=1
C
26
/W
C
/W
60
80 100 120 Temperature (C)
140
160
180
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
9
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 s pulse width. Reverse Rotation (See panel b in figure 1) When the target
referred to as reverse rotation. Reverse rotation is indicated on the output pin by a 90 s 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, fwd, results in the pulse corresponding to the valley with the sensed mechanical edge, and for targets in reverse rotation, the shift, rev, 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.
is rotating such that target teeth pass from pin 1 to pin 4, it is
(a) Forward Rotation
Pin 4 Pin 1
Reverse
Rotating Target Branded Face of Sensor
Forward
Valley
Tooth
fwd 45 s
rev
(b) Reverse Rotation
Pin 4 Pin 1
Output (Forward Rotation) Output (Reverse Rotation)
Rotating Target
Branded Face of Sensor
90 s
Figure 1. Target rotation
Figure 2. Output pulse timing
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
10
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.) The Package Thermal Resistance, RJA, 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, RJC, is relatively small component of RJA. Ambient air temperature, TA, and air motion are significant external factors, damped by overmolding. 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 x IIN T = PD x RJA TJ = TA + T (1) (2) (3) Example: Reliability for VCC at TA = 150C, package SH, using the PCB with least exposed copper. Observe the worst-case ratings for the device, specifically: RJA = 126C/W, TJ(max) = 165C, VCC(max) = 28 V, and ICC(max) = 16.8 mA. Calculate the maximum allowable power level, PD(max). First, invert equation 3: Tmax = 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) = Tmax / RJA = 15C / 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 RJA. If VCC(est) VCC(max), then operation between VCC(est) and VCC(max) is reliable under these conditions. 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. For example, when a standard diode with a 0.7 V drop is used: VS(max) = 7.1 V + 0.7 V = 7.8 V
For example, given common conditions such as: TA= 25C, VCC = 5 V, ICC = 14 mA, and RJA = 126 C/W, then: PD = VCC x ICC = 12 V x 4.0 mA = 70.0 mW T = PD x RJA = 70.0 mW x 126 C/W = 8.8C TJ = TA + T = 25C + 8.8C = 23.8C A worst-case estimate, PD(max), represents the maximum allowable power level (VCC(max), ICC(max)), without exceeding TJ(max), at a selected RJA and TA.
651LSH-DS, Rev. 3
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
11
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 E 1.50 .0591
C B
8.0 E1
E 0.23 .009
.315
5.8
.228 2.9 .114 E3 E2
4.0 5.0 .244
.157
1.7
.067 1 2 3 4
A
0.38 .015
1.08 .043 1 .039
20.95 .825 13.05 .514
A
0.6 .024
D
0.6 .024 1.27 .050
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
A
B C D E
Dambar removal protrusion (16X) Metallic protrusion, electrically connected to pin 4 and substrate (both sides) Active Area Depth, 0.43 [.017] Thermoplastic Molded Lead Bar for alignment during shipment 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 (c) 2005 Allegro MicroSystems, Inc.
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
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651LSH-DS, Rev. 3

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