DATASHEET SEARCH SITE | WWW.ALLDATASHEET.COM
Document overview
- Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
- PDF pages: 16
Technical content
Description
The ATS617 gear-tooth sensor IC is a peak-detecting device that uses automatic gain control and an integrated capacitor to provide extremely accurate gear edge detection down to low operating speeds. Each device consists of a high-temperature plastic shell that holds together a samarium-cobalt pellet, a pole piece, and a differential open-collector 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 technology used for this device is Hall-effect based. The device incorporates a dual-element Hall IC that switches in response to differential magnetic signals created by ferromagnetic targets. The sophisticated processing circuitry contains an A-to-D 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 provides immunity to magnet and system offsets and has the ability to discriminate relatively fast changes such as those caused by tilt, gear wobble, and eccentricities. This easy-to-integrate solution provides first falling edge detection and stable operation to extremely low rpm. The ATS617 can be used as a replacement for the ATS616. The ATS617 is ideal for use in systems that gather speed, position, and timing information using gear-tooth-based ATS617LSG-DS, Rev. 1 Features and Benefits ▪ Self-calibrating for tight timing accuracy ▪ First-tooth detection ▪ Immunity to air gap variation and system offsets ▪ Immunity to signature tooth offsets ▪ Integrated capacitor provides analog peak and valley information ▪ Low timing-accuracy drift with temperature changes ▪ Low radiated emissions ▪ Integrated, series resistor on VCC pin for improved transient immunity ▪ Large air gap capability ▪ Small, integrated package ▪ Optimized magnetic circuit ▪ Undervoltage lockout (UVLO) ▪ Wide operating voltage range Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC Continued on the next page… Package: 4-pin SIP (suffix SG) Not to scale ATS617LSG GND VOUT VC RS C Voltage Regulator TEST Hall Amp Reference Generator Gain Current Limit (Recommended) Hall Amp Track and Hold Track and Hold UVLO Power-On Logic Tooth and Valley Comparator Functional Block Diagram
Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor ICATS617LSG 2Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A. configurations. This device is particularly suited to those applications that require extremely accurate duty cycle control or accurate edge- detection, such as automotive camshaft sensing. The ATS617 is provided in a 4-pin SIP that is Pb (lead) free, with a 100% matte tin plated leadframe. Description (continued) Pin-out Diagram Absolute Maximum Ratings Characteristic Symbol Notes Rating Unit Supply Voltage V CC See Power Derating section 26.5 V Reverse Supply Voltage V RCC –18 V Output Off Voltage V OUTOFF 24 V Continuous Output Current I OUT 25 mA Reverse Output Current I ROUT 50 mA 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 Selection Guide Part Number Packing* ATS617LSGTN-T 13-in. reel, 800 pieces/reel *Contact Allegro® for additional packing options 24 31 Terminal List Number Name Function
1 VCC Device supply
2 VOUT Device output
3 Test Tie to GND, or float
4 GND Device ground
Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor ICATS617LSG 3Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. OPERATING CHARACTERISTICS over operating voltage and temperature range, unless otherwise noted Characteristic Symbol Test Condition Min. Typ. 1 Max. Unit
Electrical Characteristics
Supply Voltage2 VCC Operating, TJ < 165C 4.5 – 24 V Supply Protection Resistor R S –6 0 7 2 Ω Undervoltage Lockout Threshold V CC(UV) VCC = 0 → 5 V; VCC = 5 → 0 V – 3.7 – V Output On Voltage V OUT(SAT) IOUT = 15 mA, output on – 100 400 mV Supply Zener Clamp Voltage V Zsupply ICC = 15 mA, TA = 25°C 28 – – V Output Zener Clamp Voltage V Zoutput IOUT = 3 mA, TA = 25°C 30 – – V Supply Zener Current I Zsupply VS = 28 V – – 15 mA Output Zener Current I Zoutput VOUT = 30 V – – 3 mA Output Current Limit I OUTM VOUT = 12 V 25 45 55 mA Output Leakage Current I OUTOFF VOUT = 24 V, output off – – 15 μA Supply Current I CC VCC > VCC(min) 3 6 12 mA Power-On Time t PO VCC > 5 V – 80 500 μs Power-On State POS V CC = 0 → 5 V – High – V Output Rise Time3 tr RPU = 2 kΩ, CL = 4.7 nF, 10% to 90% – 21 – μs Output Fall Time t f VPU = 5 V, RPU = 2 kΩ, CL = 4.7 nF, 90% to 10% – 6 – μs VPU =12 V, RPU = 2 kΩ, CL = 4.7 nF, 90% to 10% 6 9 12 μs Performance Characteristics Operating Air Gap Range AG Allegro reference target 60+2 operating at or above Mini- mum Operating Speed 0.4 – 2.5 mm Operating Magnetic Flux Density Differential4 BAG(p-p) Operation at or above Minimum Operating Speed 60 – – G Analog Signal Bandwidth BW – 15 – kHz Minimum Operating Speed S OP Allegro 60+2 reference target 10 – – rpm Continued on the next page…
Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor ICATS617LSG 4Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. OPERATING CHARACTERISTICS (continued) over operating voltage and temperature range, unless otherwise noted Characteristic Symbol Test Condition Min. Typ. 1 Max. Unit Performance Characteristics (continued) Initial Calibration Cycle5 ncal Output edges before calibration is completed, at fsig < 100 Hz – 1 – edge Calibration Mode Disable n dis Output falling edges for startup calibration to be complete 64 64 64 edge Relative Timing Accuracy, Sequential6,7 Eθ Target Speed = 1000 rpm, BAG(p-p) > 100 G – ±0.5 ±0.75 deg. Target Speed = 1000 rpm, BAG(p-p) > 60 G – – ±1.5 deg. Allowable User Induced Differential Offset4 ∆BApp Output switching only; may not meet data sheet specifica- tions – – ±50 G Switching Hysteresis, Start-up V SWHYS(su) – 190 – mV Switching Hysteresis, Running Mode V SWHYS(rm) – 105 – mV 1 Typical data is at VCC = 12 V and TA = 25°C. Performance may vary for individual units, within the specified maximum and minimum limits. 2 Maximum voltage must be adjusted for power dissipation and junction temperature; see Power Derating section. 3 This performance is not dominated by the design of the ATS617, it is determined primarily by the external interface circuitry. 4 1 G (gauss) = 0.1 mT (millitesla), exactly. 5 Non-uniform magnetic profiles may require additional edges before calibration is complete. 6 For Allegro 60+2 reference target. 7 Accuracy may be compromised during the calibration cycle.
Worcester, Massachusetts 01615-0036 U.S.A. Figure 1. Configuration with Radial-Tooth Reference Target
Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor ICATS617LSG 6Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. Characteristic Data Continued on the next page. VCC (V) Supply Current (On) versus Supply Voltage TA (°C) ICC (mA) VCC (V) Supply Current (Off) versus Supply Voltage ICC (mA) Supply Current (Off) versus Ambient Temperature ICC (mA) 150 –40 TA (°C) Supply Current (On) versus Ambient Temperature ICC (mA) TA (°C) VCC (V) 4.5 VCC (V) 4.5 TA (°C) 150 –40 01 0 2 0 1552 5 3 0 01 0 2 0 1552 5 3 0 –50 0 50 100 150 200 –50 0 50 100 150 200
Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor ICATS617LSG 7Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. Output Voltage (On) versus Ambient Temperature VSAT(ON) (mV) VSAT(ON) (mV) Output Leakage Current (Off) versus Ambient Temperature Output Leakage Current (Off) versus Output VoltageIOUTOFF (μA) IOUTOFF (μA) IOUT (mA) VOUT (V) Output Voltage (On) versus Output Current TA (°C) TA (°C) TA (°C) 150 –40 IOUT (mA) TA (°C) 150 –40 VOUT (V) 2.5 7.5 400 300 200 100 400 300 200 100 01 0 2 0 1552 5 05 1 0 7.52.5 12.5 –50 0 50 100 150 200 –50 0 50 100 150 200 Continued on the next page.
Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor ICATS617LSG 8Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. Rising Edge Falling Edge Rising Edge Falling Edge Rising Edge Falling Edge Rising Edge Falling Edge Rising Edge Falling Edge Rising Edge Falling Edge Speed (krpm) 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Speed (krpm) 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Speed (krpm) 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Speed (krpm) 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Speed (krpm) 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Speed (krpm) 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Speed (krpm) 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Speed (krpm) 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Speed (krpm) 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Speed (krpm) 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Speed (krpm) 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Speed (krpm) 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) TA = –40°C Sequential RegionSignature Region TA = 25°C Edge Position versus Target Speed through Ambient Temperature Range TA = 150°C Continued on the next page.
Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor ICATS617LSG 9Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. Ambient Temperature (°C) -40 25 85 150 Rising Edge Falling Edge Rising Edge Falling Edge Rising Edge Falling Edge Rising Edge Falling Edge Rising Edge Falling Edge Rising Edge Falling Edge Air Gap (mm) 0 1.0 2.0 3.0 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Air Gap (mm) 0 1.0 2.0 3.0 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Air Gap (mm) 0 1.0 2.0 3.0 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Air Gap (mm) 0 1.0 2.0 3.0 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Air Gap (mm) 0 1.0 2.0 3.0 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Air Gap (mm) 0 1.0 2.0 3.0 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Air Gap (mm) 0 1.0 2.0 3.0 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Air Gap (mm) 0 1.0 2.0 3.0 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Air Gap (mm) 0 1.0 2.0 3.0 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Air Gap (mm) 0 1.0 2.0 3.0 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Air Gap (mm) 0 1.0 2.0 3.0 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Air Gap (mm) 0 1.0 2.0 3.0 1.5 1.0 0.5 -0.5 -1.0 -1.5 Edge Position (°) Speed = 10 rpm Sequential RegionSignature Region Speed = 500 rpm Edge Position versus Air Gap through Target Speed Range Speed = 2000 rpm
Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor ICATS617LSG 10Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information Characteristic Symbol Test Conditions* Value Units Package Thermal Resistance RθJA Single-sided PCB with copper limited to solder pads 126 ºC/W Two-sided PCB with copper limited to solder pads and 3.57 in.2 (23.03 cm2) of copper area each side, connected to GND pin 84 ºC/W *Additional information is available on the Allegro website. 20 40 60 80 100 120 140 160 180 Temperature (ºC) Maximum Allowable VCC (V) TJ(max) = 165ºC; ICC = ICC(max) Power Derating Curve (RQJA = 126 ºC/W) (RQJA = 84 ºC/W) 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 = VCC(max); ICC = ICC(max) Maximum Power Dissipation, PD(max) θJA = 126 ºC/W) θJA = 84 ºC/W
Worcester, Massachusetts 01615-0036 U.S.A. perature materials are used in all aspects of construction. peak detection scheme to eliminate magnet and system offsets. circuit sets the gain of the device after power-on. Figure 2. Relative motion of the target is detected by the dual Hall ele- ments mounted on the Hall IC. Figure 3. The peaks in the resulting differential signal are used to set the operate, BOP , and release, BRP , switchpoints.
Worcester, Massachusetts 01615-0036 U.S.A.
- 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 varia- tion caused by air gap changes is minimized by the self-calibra- tion circuitry. A 2×-to-3× improvement can be seen.
- Dual edge detection. Because this device switches based on the positive and negative peaks of the signal, dual edge detection is guaranteed.
- Tilted or off-center installation. Traditional differential sensors can switch incorrectly due to baseline changes versus air gap caused by tilted or off-center installation. The peak detector cir- cuitry references the switchpoint 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 achiev- able with this device due to the sensitive switchpoints after power-on (dependent on target dimensions, material, and speed).
- Immunity to magnetic overshoot. The patented adjustable hysteresis circuit makes the ATS617 immune to switching on magnetic overshoot within the specified air gap range.
- 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 gain-adjust circuitry keeps the hysteresis of the device roughly proportional to the peak-to-peak signal. This allows the device to have good im- munity to vibration even when operating at close air gaps.
- Immunity to gear run out. The differential chip configuration eliminates the baseline variations caused by gear run out Differential vs. Single-Element Design The differential chip is superior in most applications to the classical single-ele- ment design. The single-element configuration commonly used (Hall-effect element 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, valley widths, eccentricities, and vibration (figure 4). The differential configuration (figure 5) cancels the effects of the back-biased field and avoids many of the issues presented by the single Hall element design.
Figure 4. Affect of varying valley widths on single-element circuits. Figure 5. Affect of varying air gaps on differential circuits.
Worcester, Massachusetts 01615-0036 U.S.A. value even though the circuit may power-on over a large signal. both at power-on and while running. detectors, which switch at half the peak-to-peak signal. edge that results in a high-to-low transition of the device output. leading edge passes the unit. Figure 6. This left-to-right (pin 1 to pin 4) direction of target rotation inverts the output signal polarity. Figure 7. The magnetic profile reflects the geometry of the target, allowing the device to present an accurate digital output response.
Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor ICATS617LSG 14Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. 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 supplied power or improving the heat dissipation properties of the appli- cation. This section presents a procedure for correlating factors affecting operating T J. (Thermal data is also available on the Allegro MicroSystems website.) The Package Thermal Resistance, RJA, 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 JC, 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 T J, at PD. P D = VIN × IIN (1) T J = TA + ΔT (3) For example, given common conditions such as: TA= 25°C, VCC = 12 V, ICC = 6 mA, and RJA = 126 °C/W, then: P D = VCC × ICC = 12 V × 6 mA = 72 mW T = PD × RJA = 72 mW × 126 °C/W = 9°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 RJA and TA. Example: Reliability for VCC at TA = 150°C, package SG, using minimum-K PCB. Observe the worst-case ratings for the device, specifically: RJA = 126 °C/W, TJ(max) = 165°C, VCC(max) = 24 V , and ICC(max) = 12 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 = 15°C ÷ 126 °C/W = 119 mW Finally, invert equation 1 with respect to voltage: VCC(est) = PD(max) ÷ ICC(max) = 119 mW ÷ 12 mA = 9.92 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 ATS617 chip. If a protective series diode or resistor is used, the effec- tive maximum supply voltage is increased. For example, when a standard diode with a 0.7 V drop is used: V CC(max) = 9.9 V + 0.7 V = 10.6 V
Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor ICATS617LSG 15Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. 0.71±0.05 5.50±0.05 4.70±0.10 0.60±0.10 0.40±0.10 24.65±0.10 15.30±0.10
1.0 REF
1.60±0.10 1.27±0.10 5.50±0.10 8.00±0.05 5.80±0.05 1.70±0.10 24 31 A A D B For Reference Only, not for tooling use (reference DWG-9002) Dimensions in millimeters A B C C D E F F Dambar removal protrusion (16X) Metallic protrusion, electrically connected to pin 4 and substrate (both sides) Thermoplastic Molded Lead Bar for alignment during shipment E E2E1 Hall elements (E1, E2), not to scale Active Area Depth, 0.43 mm Branded Face Standard Branding Reference View = Supplier emblem L = Lot identifier N = Last three numbers of device part number Y = Last two digits of year of manufacture W = Week of manufacture LLLLLLL YYWW NNN Branding scale and appearance at supplier discretion 0.38 +0.06 –0.04 2.20 Package SG 4-Pin SIP
Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor ICATS617LSG 16Allegro MicroSystems, LLC Worcester, Massachusetts 01615-0036 U.S.A. Copyright ©2013, Allegro MicroSystems, LLC The products described herein are manufactured under one or more of the following U.S. patents: 5,264,783; 5,389,889; 5,442,283; 5,517,112; patents pending. Allegro MicroSystems, LLC 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’s products are not to be used in life support devices or systems, if a failure of an Allegro product can reasonably be expected to cause the failure of that life support device or system, or to affect the safety or effectiveness of that device or system. The in for ma tion in clud ed herein is believed to be ac cu rate and reliable. How ev er, Allegro MicroSystems, LLC 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. For the latest version of this document, visit our website: www.allegromicro.com