AATS643LSH

AATS643LSH_06 ALLEGRO | Alldatasheet

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Description

The ATS643 is an optimized combination of integrated circuit and magnet that provides a manufacturer-friendly solution for true zero-speed digital gear-tooth sensing in two-wire applications. The device consists of a single-shot molded plastic package that includes a samarium cobalt magnet, a pole piece, and a Hall-effect IC that has been optimized to the magnetic circuit and the automotive environment. This small package can be easily assembled and used in conjunction with a wide variety of gear shapes and sizes. The integrated circuit incorporates a dual element Hall-effect sensor with signal processing circuitry that switches in response to differential magnetic signals created by rotating ferrous targets. The device contains a sophisticated compensating circuit to eliminate magnet and system offsets immediately at power-on. Digital tracking of the analog signal is used to achieve true zero-speed operation, while also setting the device switchpoints. The resulting switchpoints are air gap independent, greatly improving output and duty cycle accuracy. The device also uses a continuous update algorithm to fine- tune the switchpoints while in running mode, maintaining ATS643-DS, Rev. 2 Features and Benefits ▪ Fully-optimized differential digital gear tooth sensor ▪ Single chip-IC for high reliability ▪ Internal current regulator for 2-wire operation ▪ Small mechanical size (8 mm diameter x 5.5 mm depth) ▪ Switchpoints air gap independent ▪ Digital output representing gear profile ▪ Precise duty cycle accuracy throughout temperature range ▪ Large operating air gaps ▪ <2 ms power-on time Self-Calibrating, Zero-Speed Differential Gear Tooth Sensor with Continuous Update Continued on the next page… Functional Block Diagram Not to scale Packages: 4 pin SIP (suffix SH) ATS643LSH Hall AMP AGC Threshold Logic ThresholdP ThresholdN PDAC Internal Regulator VCC (Pin 1) NDAC GND (Pin 4) Reference Generator and Updates Offset Adjust Continued on the next page…

Self-Calibrating, Zero-Speed Differential Gear Tooth Sensor with Continuous UpdateATS643LSH 2Allegro MicroSystems, Inc.

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Part Number Pb-free 1 Packing2 ICC Typical ATS643LSHTN-I1-T Yes Tape and Reel 13-in. 800 pcs./reel 6.0 Low to 14.0 High mA ATS643LSHTN-I2-T Yes Tape and Reel 13-in. 800 pcs./reel 7.0 Low to 14.0 High mA 1Pb-based variants are being phased out of the product line. Certain variants cited in this footnote are in production but have been determined to be NOT FOR NEW DESIGN. This classification indicates that sale of this device is currently restricted to existing customer applications. The device should not be purchased for new design applications because obsolescence in the near future is probable. Samples are no longer available. Status change: May 1, 2006. These variants include: ATS643LSHTN-I1 and ATS643LSHTN-I2. 2Contact Allegro for additional packing options. 3Some restrictions may apply to certain types of sales. Contact Allegro for details. ▪ AGC and reference adjust circuit ▪ True zero-speed operation ▪ Undervoltage lockout ▪ Wide operating voltage range ▪ Defined power-on state the device specifications even through large changes in air gap or temperature. The regulated current output is configured for two-wire operation, offering inherent diagnostic information. This device is ideal for obtaining speed and duty cycle information in gear-tooth based applications such as transmission speed sensing. Features and Benefits (continued) Description (continued) Absolute Maximum Ratings Characteristic Symbol Notes Rating Units Supply Voltage V CC See Power Derating section – – Reverse-Supply Voltage V RCC –18 V Operating Ambient Temperature T A Range L –40 to 150 ºC Maximum Junction Temperature T J(max) 165 ºC Storage Temperature T stg –65 to 170 ºC Terminal List Name Description Number VCC Connects power supply to chip 1 NC No connection. Float or tie to VCC 2 TEST For Allegro use, float or tie to GND 3 GND Ground terminal 4 2 431 Pin-out Diagram

Self-Calibrating, Zero-Speed Differential Gear Tooth Sensor with Continuous UpdateATS643LSH 3Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com OPERATING CHARACTERISTICS using reference target 60-0, TA and VCC within specification, unless otherwise noted Characteristic Symbol Test Conditions Min. Typ. Max. Units

ELECTRICAL CHARACTERISTICS

CC Operating; TJ < 165 °C 4.0 – 24 V Undervoltage Lockout V CC(UV) VCC 0 → 5 V – 3.5 4.0 V Supply Zener Clamp Voltage V Z ICC = 19 mA for ATS643-I1, and 19.8 mA for ATS643-I2; TA = 25°C 28 – – V Supply Current ICC(Low) ATS643-I1 4.0 6 8.0 mA ATS643-I2 5.9 7 8.4 mA ICC(High) ATS643-I1 12.0 14.0 16.0 mA ATS643-I2 11.8 14.0 16.8 mA Supply Current Ratio ICC(High)/ ICC(Low) Ratio of high current to low current 1.85 – 3.05 – POWER-ON CHARACTERISTICS Power-On State I CC(PO) t < ton; dI/dt < 5 μs – High – mA Power-On Time1 ton Target gear speed < 100 rpm – 1 2 ms OUTPUT STAGE Output Slew Rate 2 dI/dt R LOAD = 100 Ω, CLOAD = 10 pF – 7 – mA/ μs Output State V OUT RSENSE on high side (VCC pin); ICC = ICC(High) – Low – mV RSENSE on low side (GND pin); ICC = ICC(High) – High – mV Continued on the next page.

Self-Calibrating, Zero-Speed Differential Gear Tooth Sensor with Continuous UpdateATS643LSH 4Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com OPERATING CHARACTERISTICS (continued) using reference target 60-0, TA and VCC within specification, unless otherwise noted Characteristic Symbol Test Conditions Min. Typ. Max. Units SWITCHPOINT CHARACTERISTICS Rotation Speed S ROT Reference Target 60-0 0 – 12,000 rpm Bandwidth BW Equivalent to f – 3dB 25 40 – kHz Operate Point B OP % of peak to peak referenced from PDAC to NDAC, AG < AGMAX –6 5– % Release Point B RP % of peak to peak referenced from PDAC to NDAC, AG < AGMAX –3 5– % CALIBRATION3 Initial Calibration Period C I Quantity of rising output (current) edges required for accurate edge detection – – 3 Edge AGC Calibration Disable C f Quantity of rising output (current) edges used for calibrating AGC – – 3 Edge Start Mode Hysteresis PO HYS – 175 – mV DAC CHARACTERISTICS Dynamic Offset Cancellation – ±60 – G Tracking Data Resolution Quantity of bits available for PDAC/NDAC tracking of both positive and negative signal peaks –9– B i t FUNCTIONAL CHARACTERISTICS Air Gap Range 4 AG ΔDC within specification 0.5 – 2.5 mm Maximum Operable Air Gap AG (opmax) Output switching (no missed edges); ΔDC not guaranteed – – 2.75 mm Duty Cycle Variation ΔDC Wobble < 0.5 mm, AG within specification – – ±10 % Input Signal Range Sig ΔDC within specification 40 – 1400 G Minimum Operable Input Signal Sig (opmin) Output switching (no missed edges); ΔDC not guaranteed 30 – – G 1Power-On Time includes the time required to complete the internal automatic offset adjust. The DACs are then ready for peak acquisition. 2dI is the difference between 10% of ICC(Low) and 90% of ICC(High) , and dt is time period between those two points. Note: dI/dt is dependent upon the value of the bypass capacitor, if one is used. 3Continuous Update (calibration) functions continuously during Running mode operation. 4AG is dependent on the available magnetic field. The available field is dependent on target geometry and material, and should b e independently characterized. The field available from the reference target is given in the reference target parameter section of the datasheet.

Self-Calibrating, Zero-Speed Differential Gear Tooth Sensor with Continuous UpdateATS643LSH 5Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Reference Gear Magnetic Profile Two Tooth-to-Valley Transitions -700 -600 -500 -400 -300 -200 -100 100 200 300 400 500 600 700 0123456789 1 0 1 1 1 2 Gear Rotation (°) Differential B* (G) 0.50 mm AG 2.00 mm AG 0.50 0.75 1.00 1.25 1.50 1.75 2.00 AG (mm) Reference Gear Magnetic Gradient Amplitude with Reference to Air Gap 200 400 600 800 1000 1200 1400 1600 1800 AG (mm) Peak-to-Peak Differential B* (G) 0.5 1 1.5 2 2.5 REFERENCE TARGET, 60-0 (60 Tooth Target) Characteristics Symbol Test Conditions Typ. Units Symbol Key Outside Diameter D o Outside diameter of target 120 mm Face Width F Breadth of tooth, with respect to sensor 6m m Circular Tooth Length t Length of tooth, with respect to sensor; measured at Do 3m m Circular Valley Length t v Length of valley, with respect to sensor; measured at Do 3m m Tooth Whole Depth h t 3m m Material Low Carbon Steel – – *Differential B corresponds to the calculated difference in the magnetic fi eld as sensed simultaneously at the two Hall elements in the device (BDIFF = BE1 – BE2). Reference Target 60-0 of Sensor Branded Face

Self-Calibrating, Zero-Speed Differential Gear Tooth Sensor with Continuous UpdateATS643LSH 6Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Characteristic Data Data taken from 3 lots, 30 pieces/lot; I1 trim Reference Target 60-0 Duty Cycle at 1000RPM –50 0 50 100 150 200 TA (°C) Duty Cycle (%) Duty Cycle at 1000RPM 00 . 511 . 522 . 533 . 5 AG (mm) Duty Cycle (%) -40 150 Duty Cycle (25°C) 0 500 1000 1500 2000 2500 RPM Duty Cycle (%) TA (ºC) 3.0 2.75 2.5 2.25 2.0 1.5 1.0 0.5 AG (mm) 3.0 2.75 2.5 2.25 2.0 1.5 1.0 0.5 AG (mm) Continued on the next page.

Self-Calibrating, Zero-Speed Differential Gear Tooth Sensor with Continuous UpdateATS643LSH 7Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Characteristic Data (continued) Data taken from 3 lots, 30 pieces/lot; I1 trim ICC (Low) –50 0 50 100 150 200 Icc (mA) ICC(Low) 0 5 10 15 20 25 30 Vcc (V) Icc (mA) ICC(High) –50 0 50 100 150 200 TA (°C) Icc (mA) 26.5V 20V 12V ICC(High) 0 5 10 15 20 25 30 Vcc (V) Icc (mA) TA (°C) 26.5 20.0 12.0 4.0 VCC 26.5 20.0 12.0 4.0 VCC 150 –40 TA (ºC) 150 –40 TA (ºC) BOP BRP BHYS ICC(High) ICC ICC(Low) Switch to High Switch to Low Hysteresis ofΔIICC Switching Due toΔB Output current in relation to sensed mag- netic flux density. Transition through BOP must precede by transition through BRP.

Self-Calibrating, Zero-Speed Differential Gear Tooth Sensor with Continuous UpdateATS643LSH 8Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information Characteristic Symbol Test Conditions Min. Typ. Max Units Package Thermal Resistance RθJA Minimum-K PCB (single-sided with copper limited to solder pads) 126 – – ºC/W Low-K PCB (single-sided with copper limited to solder pads and 3.57 in.2 (23.03 cm2) of copper area) 84 – – ºC/W 20 40 60 80 100 120 140 160 180 Maximum Allowable VCC (V) TJ(max) = 165ºC; ICC =I CC(max) Power Derating Curve (RθJA = 126 ºC/W) Minimum-K PCB (RθJA = 84 ºC/W) Low-K PCB VCC(min) VCC(max) 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 20 40 60 80 100 120 140 160 180 Temperature (°C) Power Dissipation, PD (mW) TJ(max) = 165ºC; VCC =V CC(max);I CC =I CC(max) Maximum Power Dissipation, PD(max) θJA =1 2 6º C/W) Minimum-K PCB θJA = 84 ºC/W) Low-K P CB

precise switching of the digital output signal. profile that it induces, to the digital output signal of the ATS643. incremental assembly costs for most applications. Figure 1. Relative motion of the target is detected by the dual Hall ele- ments mounted on the Hall IC. Figure 2. This left-to-right (pin 1 to pin 4) direction of target rotation tion inverts the output signal polarity. Figure 3. The magnetic profile reflects the geometry of the target, allow- ing the ATS643 to present an accurate digital output response.

10Allegro MicroSystems, Inc. release point, BRP , the switch toggles from on to off. manner, variations are tracked in real time. Figure 4. The Continuous Update algorithm allows the Allegro sensor to immediately interpret and adapt to significant variances in the magnetic field it remains properly proportioned and centered within the peak-to-peak range of the internal analog signal, VPROC. switchpoints based on the fluctuation of VPROC, as shown in panel C.

1 BOP(#1) Pk(#1), Pk(#2)

2 BOP(#2) Pk(#3), Pk(#4)

3 BOP(#3) Pk(#5), Pk(#6)

11Allegro MicroSystems, Inc. power-on in the high current state, ICC(High). Figure 5. Power-on initial edge detection. This figure demonstrates four typical power-on scenarios. All of these examples assume that the target is AGC calibration begins. Three high peaks are always required for AGC calibration.

12Allegro MicroSystems, Inc. be performed using the actual target features. ATS643 starts to compute switchpoints. Figure 6. Operation of Start Mode Hysteresis Position 1. At power-on, the ATS643 begins sampling VPROC. Hysteresis can be generated either by a legitimate target feature or by excessive vibration. Position 3. In this example, the first switchpoint transition is through BOP . and the output transitions from high to low. polarity. The first transition would occur at position 5 (BOP).

13Allegro MicroSystems, Inc. ure 7 for an example of a basic application circuit. temperature variations over time. materials are used in all aspects of construction.

2 ATS643

Figure 7. Typical basic circuit for proper device operation. Figure 8. Automatic Gain Control (AGC). The AGC function corrects for device performance, a shown in the lowest panel.

Self-Calibrating, Zero-Speed Differential Gear Tooth Sensor with Continuous UpdateATS643LSH 14Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Power Derating The device must be operated below the maximum junction temperature of the device, T J(max). Under certain combinations of peak conditions, reliable operation may require derating sup- plied power or improving the heat dissipation properties of the application. This section presents a procedure for correlating factors affecting operating T J. (Thermal data is also available on the Allegro MicroSystems Web site.) The Package Thermal Resistance, RθJA, is a figure of merit sum- marizing 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, R θJC, is relatively small component of RθJA. 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 T J, at PD. PD = VIN × IIN (1) Δ T = PD × RθJA (2) T J = TA + ΔT (3) For example, given common conditions such as: TA= 25°C, VCC = 12 V, ICC = 4 mA, and RθJA = 140 °C/W, then: P D = VCC × ICC = 12 V × 4 mA = 48 mW Δ T = PD × RθJA = 48 mW × 140 °C/W = 7°C T J = TA + ΔT = 25°C + 7°C = 32°C A worst-case estimate, PD(max), represents the maximum allow- able power level (VCC(max), ICC(max)), without exceeding TJ(max), at a selected RθJA and TA. Example: Reliability for VCC at TA = 150°C, package L-I1, using minimum-K PCB Observe the worst-case ratings for the device, specifically: RθJA = 126°C/W, TJ(max) = 165°C, VCC(max) = 24 V , and ICC(max) = 16 mA. Calculate the maximum allowable power level, PD(max). First, invert equation 3: 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 mA = 7 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 reli- able 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.

Self-Calibrating, Zero-Speed Differential Gear Tooth Sensor with Continuous UpdateATS643LSH 15Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Package SH, 4-pin SIP 1.08 .043 8.0 .315 5.5 .217 0.38 .015 5.0 .244 5.8 .228 4.0 .157 1.7 .067 1 .039 0.6 .024 0.6 .024 1.27 .050 20.95 .825 13.05 .514 Dimensions in millimeters. Untoleranced dimensions are nominal. U.S. Customary dimensions (in.) in brackets, for reference only 24 31 A A A B C D D B Dambar removal protrusion (16X) Metallic protrusion, electrically connected to pin 4 and substrate (both sides) Active Area Depth Thermoplastic Molded Lead Bar for alignment during shipment

Self-Calibrating, Zero-Speed Differential Gear Tooth Sensor with Continuous UpdateATS643LSH 16Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com The products described herein are manufactured under one or more of the following U.S. patents: 5,045,920; 5,264,783; 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 de par tures from the detail spec i fi ca tions as may be required to permit improvements in the per for mance, 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 compo- nents in life-support devices or sys tems without express written approval. The in for ma tion in clud ed herein is believed to be ac cu rate and reliable. How ev er, Allegro MicroSystems, Inc. assumes no re spon - si bil i ty for its use; nor for any in fringe ment of patents or other rights of third parties which may result from its use. Copyright © 2004, 2006 Allegro MicroSystems, Inc.