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