ATS617LSG

ATS617LSG Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC 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 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-tointegrate 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 Package: 4-pin SIP (suffix SG) Not to scale Continued on the next page… Functional Block Diagram VCC RS Voltage Regulator Power-On Logic Tooth and Valley Comparator VOUT Hall Amp Gain Track and Hold Reference Generator Hall Amp Current Limit UVLO Track and Hold GND (Recommended) TEST ATS617LSG-DS, Rev. 1 ATS617LSG Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC Description (continued) 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. Selection Guide Part Number Packing* ATS617LSGTN-T 13-in. reel, 800 pieces/reel *Contact Allegro® for additional packing options Absolute Maximum Ratings Characteristic Supply Voltage Reverse Supply Voltage Output Off Voltage Continuous Output Current Reverse Output Current Operating Ambient Temperature Maximum Junction Temperature Storage Temperature Symbol VCC VRCC VOUTOFF IOUT IROUT TA TJ(max) Tstg Range L Notes See Power Derating section Rating 26.5 –18 24 25 50 –40 to 150 165 –65 to 170 Unit V V V mA mA ºC ºC ºC Pin-out Diagram Terminal List Number 1 1 2 3 4 Name VCC VOUT Test GND Device supply Device output Tie to GND, or float Device ground Function 2 3 4 Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 2 ATS617LSG Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC OPERATING CHARACTERISTICS over operating voltage and temperature range, unless otherwise noted Characteristic Electrical Characteristics Supply Voltage2 Supply Protection Resistor Undervoltage Lockout Threshold Output On Voltage Supply Zener Clamp Voltage Output Zener Clamp Voltage Supply Zener Current Output Zener Current Output Current Limit Output Leakage Current Supply Current Power-On Time Power-On State Output Rise Time3 Output Fall Time Performance Characteristics Operating Air Gap Range Operating Magnetic Flux Density Differential4 Analog Signal Bandwidth Minimum Operating Speed AG BAG(p-p) BW SOP Allegro 60+2 reference target Allegro reference target 60+2 operating at or above Minimum Operating Speed Operation at or above Minimum Operating Speed 0.4 60 – 10 – – 15 – 2.5 – – – mm G kHz rpm VCC RS VCC(UV) VCC = 0 → 5 V; VCC = 5 → 0 V Operating, TJ < 165C 4.5 – – – 28 30 – – 25 – 3 – – – – 6 – 60 3.7 100 – – – – 45 – 6 80 High 21 6 9 24 72 – 400 – – 15 3 55 15 12 500 – – – 12 V Ω V mV V V mA mA mA μA mA μs V μs μs μs Symbol Test Condition Min. Typ.1 Max. Unit VOUT(SAT) IOUT = 15 mA, output on VZsupply VZoutput IZsupply IZoutput IOUTM IOUTOFF ICC tPO POS tr tf ICC = 15 mA, TA = 25°C IOUT = 3 mA, TA = 25°C VS = 28 V VOUT = 30 V VOUT = 12 V VOUT = 24 V, output off VCC > VCC(min) VCC > 5 V VCC = 0 → 5 V RPU = 2 kΩ, CL = 4.7 nF, 10% to 90% VPU = 5 V, RPU = 2 kΩ, CL = 4.7 nF, 90% to 10% VPU =12 V, RPU = 2 kΩ, CL = 4.7 nF, 90% to 10% Continued on the next page… Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 3 ATS617LSG Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC OPERATING CHARACTERISTICS (continued) over operating voltage and temperature range, unless otherwise noted Characteristic Performance Characteristics (continued) Initial Calibration Cycle5 Calibration Mode Disable Relative Timing Accuracy, Sequential6,7 Allowable User Induced Differential Offset4 Switching Hysteresis, Start-up Switching Hysteresis, Running Mode 1 Typical 2 Symbol Test Condition Min. Typ.1 Max. Unit ncal ndis Eθ ∆BApp VSWHYS(su) VSWHYS(rm) Output edges before calibration is completed, at fsig < 100 Hz Output falling edges for startup calibration to be complete Target Speed = 1000 rpm, BAG(p-p) > 100 G Target Speed = 1000 rpm, BAG(p-p) > 60 G Output switching only; may not meet data sheet specifications – 64 – – – – – 1 64 ±0.5 – – 190 105 – 64 ±0.75 ±1.5 ±50 – – edge edge deg. deg. G mV mV data is at VCC = 12 V and TA = 25°C. Performance may vary for individual units, within the specified maximum and minimum limits. Maximum voltage must be adjusted for power dissipation and junction temperature; see Power Derating section. 3 This performance is not affected by the design of the ATS617, it is determined only 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. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 4 ATS617LSG Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC Reference Target (Gear) Information REFERENCE TARGET 60+2 SymCharacteristics bol Outside Diameter Do Face Width Angular Tooth Thickness Signature Region Angular Tooth Thickness Angular Valley Thickness Tooth Whole Depth Material F t Test Conditions Outside diameter of target Breadth of tooth, with respect to branded face Length of tooth, with respect to branded face; measured at Do Length of signature tooth, with respect to branded face; measured at Do Length of valley, with respect to branded face; measured at Do Low Carbon Steel Typ. 120 6 3 Units mm mm deg. tSIG t Do F ht Symbol Key tSIG tv ht 15 deg. Air Gap tv 3 3 – deg. mm – Branded Face of Package Signature Region Pin 4 Pin 1 Branded Face of Package Reference Target 60+2 Figure 1. Configuration with Radial-Tooth Reference Target Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 5 ATS617LSG Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC Characteristic Data Supply Current (On) versus Supply Voltage 12 11 10 9 8 7 6 5 4 3 0 5 10 15 VCC (V) 20 25 30 Supply Current (On) versus Ambient Temperature 12 11 10 TA (°C) –40 25 85 150 9 8 7 6 5 4 3 –50 0 50 TA (°C) 100 150 200 VCC (V) 4.5 12 18 24 ICCON (mA) Supply Current (Off) versus Supply Voltage 12 11 10 ICCON (mA) Supply Current (Off) versus Ambient Temperature 12 11 10 ICCOFF (mA) ICCOFF (mA) 9 8 7 6 5 4 3 0 5 10 15 VCC (V) 20 25 30 TA (°C) –40 25 85 150 9 8 7 6 5 4 3 –50 0 50 TA (°C) 100 150 200 VCC (V) 4.5 12 18 24 Continued on the next page. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 6 ATS617LSG Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC Output Voltage (On) versus Ambient Temperature 400 400 Output Voltage (On) versus Output Current VSAT(ON) (mV) IOUT (mA) 200 5 10 15 20 VSAT(ON) (mV) 300 300 TA (°C) –40 25 85 150 200 100 100 0 –50 0 0 50 TA (°C) 100 150 200 0 5 10 IOUT (mA) 15 20 25 Output Leakage Current (Off) versus Ambient Temperature 15 Output Leakage Current (Off) versus Output Voltage 15 IOUTOFF (μA) ICCOFF (μA) 10 VOUT (V) 2.5 5 7.5 10 10 5 5 TA (°C) –40 25 85 150 0 –50 0 0 50 TA (°C) 100 150 200 0 2.5 5 VOUT (V) 7.5 10 12.5 Continued on the next page. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 7 ATS617LSG Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC Edge Position versus Target Speed through Ambient Temperature Range TA = –40°C Rising Edge 1.5 Edge Position (°) Edge Position (°) 1.0 0.5 0 -0.5 -1.0 -1.5 0 0.5 1.0 1.5 Speed (krpm) 2.0 2.5 1.5 Edge Position (°) 1.0 0.5 0 -0.5 -1.0 -1.5 0 0.5 1.0 1.5 Speed (krpm) 2.0 2.5 TA = 25°C Rising Edge 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 0 0.5 TA = 150°C Rising Edge Sequential Region 1.0 1.5 Speed (krpm) 2.0 2.5 Falling Edge 1.5 Edge Position (°) Edge Position (°) 1.0 0.5 0 -0.5 -1.0 -1.5 0 0.5 1.0 1.5 Speed (krpm) 2.0 2.5 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 0 0.5 Falling Edge 1.5 Edge Position (°) 1.0 0.5 0 -0.5 -1.0 -1.5 1.0 1.5 Speed (krpm) 2.0 2.5 0 0.5 Falling Edge 1.0 1.5 Speed (krpm) 2.0 2.5 Rising Edge 1.5 Edge Position (°) Edge Position (°) 1.0 0.5 0 -0.5 -1.0 -1.5 0 0.5 1.0 1.5 Speed (krpm) 2.0 2.5 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 0 0.5 Rising Edge 1.5 Edge Position (°) 1.0 0.5 0 -0.5 -1.0 -1.5 1.0 1.5 Speed (krpm) 2.0 2.5 0 0.5 Rising Edge Signature Region 1.0 1.5 Speed (krpm) 2.0 2.5 Falling Edge 1.5 Edge Position (°) Edge Position (°) 1.0 0.5 0 -0.5 -1.0 -1.5 0 0.5 1.0 1.5 Speed (krpm) 2.0 2.5 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 0 0.5 Falling Edge 1.5 Edge Position (°) 1.0 0.5 0 -0.5 -1.0 -1.5 1.0 1.5 Speed (krpm) 2.0 2.5 0 0.5 Falling Edge 1.0 1.5 Speed (krpm) 2.0 2.5 Air Gap (mm) 0.5 1.0 1.5 2.2 2.5 Continued on the next page. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 8 ATS617LSG Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC Edge Position versus Air Gap through Target Speed Range Speed = 10 rpm Rising Edge 1.5 Edge Position (°) Edge Position (°) 1.0 0.5 0 -0.5 -1.0 -1.5 0 1.0 2.0 Air Gap (mm) 3.0 1.5 Edge Position (°) 1.0 0.5 0 -0.5 -1.0 -1.5 0 1.0 2.0 Air Gap (mm) 3.0 Speed = 500 rpm Rising Edge 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 0 Speed = 2000 rpm Rising Edge Sequential Region 1.0 2.0 Air Gap (mm) 3.0 Falling Edge 1.5 Edge Position (°) Edge Position (°) 1.0 0.5 0 -0.5 -1.0 -1.5 0 1.0 2.0 Air Gap (mm) 3.0 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 0 Falling Edge 1.5 Edge Position (°) 1.0 0.5 0 -0.5 -1.0 -1.5 1.0 2.0 Air Gap (mm) 3.0 0 Falling Edge 1.0 2.0 Air Gap (mm) 3.0 Rising Edge 1.5 Edge Position (°) Edge Position (°) 1.0 0.5 0 -0.5 -1.0 -1.5 0 1.0 2.0 Air Gap (mm) 3.0 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 0 Rising Edge 1.5 Edge Position (°) 1.0 0.5 0 -0.5 -1.0 -1.5 1.0 2.0 Air Gap (mm) 3.0 0 Rising Edge Signature Region 1.0 2.0 Air Gap (mm) 3.0 Falling Edge 1.5 Edge Position (°) Edge Position (°) 1.0 0.5 0 -0.5 -1.0 -1.5 0 1.0 2.0 Air Gap (mm) 3.0 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 0 Falling Edge 1.5 Edge Position (°) 1.0 0.5 0 -0.5 -1.0 -1.5 1.0 2.0 Air Gap (mm) 3.0 0 Falling Edge 1.0 2.0 Air Gap (mm) 3.0 Ambient Temperature (°C) -40 25 85 150 Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 9 ATS617LSG Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information Characteristic Package Thermal Resistance Symbol RθJA Test Conditions* Single-sided PCB with copper limited to solder pads Two-sided PCB with copper limited to solder pads and 3.57 (23.03 cm2) of copper area each side, connected to GND pin in.2 Value 126 84 Units ºC/W ºC/W *Additional information is available on the Allegro website. 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 Power Derating Curve TJ(max) = 165ºC; ICC = ICC(max) VCC(max) Maximum Allowable VCC (V) (R JA = 84 ºC/W) (R JA = 126 ºC/W) VCC(min) 60 80 100 120 140 160 180 Temperature (ºC) 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 800 700 600 500 400 300 200 100 0 20 Maximum Power Dissipation, PD(max) TJ(max) = 165ºC; VCC = VCC(max); ICC = ICC(max) Power Dissipation, PD (m W) (R θJ A (R = θJ 84 A =1 ºC 26 /W ºC ) /W ) 40 60 80 100 120 Temperature (°C) 140 160 180 Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 10 ATS617LSG Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC Functional Description Assembly Description The ATS617 gear-tooth sensor IC is a Hall IC/rare-earth pellet configuration that is fully optimized to provide detection of gear tooth edges. This device is packaged in a molded miniature plastic body that has been optimized for size, ease of assembly, and manufacturability. High operating temperature materials are used in all aspects of construction. After proper power is applied to the component, the chip is capable of instantly providing digital information that is representative of the profile of a rotating gear. No additional optimization or processing circuitry is required. This ease of use should reduce design time and incremental assembly costs for most applications. Hall Technology The ATS617 contains a single-chip differential Hall effect sensor IC, a samarium cobalt pellet, and a flat ferrous pole piece (figure 2). The Hall IC consists of 2 Hall elements (spaced 2.2 mm apart) located so as to measure the magnetic gradient created by the passing of a ferrous object. The two elements measure the magnetic gradient and convert it to an analog voltage that is then processed in order to provide a digital output signal. The Hall IC is self-calibrating and also possesses a temperature compensated amplifier and offset cancellation circuitry. Its voltage regulator provides supply noise rejection throughout the operating voltage range. Changes in temperature do not greatly affect this device due to the stable amplifier design and the offset rejection circuitry. The Hall transducers and signal processing electronics are integrated on the same silicon substrate, using a proprietary BiCMOS process. Internal Electronics The processing circuit uses a patented peak detection scheme to eliminate magnet and system offsets. This technique allows dynamic coupling and filtering of offsets without the power-up and settling time disadvantages of classical high-pass filtering schemes. The peak signal of every tooth and valley is detected by the filter and is used to provide an instant reference for the operate and release point comparator. In this manner, the thresholds are adapted and referenced to individual signal peaks and valleys, providing immunity to zero line variation from installation inaccuracies (tilt, rotation, and off-center placement), as well as for variations caused by target and shaft eccentricities. The ATS617 also includes self-calibration circuitry that is engaged at power on. The signal amplitude is measured, and then the device gain is normalized. In this manner switchpoint drift versus air gap is minimized, and excellent timing accuracy can be achieved. The AGC (Automatic Gain Control) circuitry, in conjunction with a unique hysteresis circuit, also eliminates the effect of gear edge overshoot as well as increases the immunity to false switching caused by gear tooth anomalies at close air gaps. The AGC circuit sets the gain of the device after power-on. V+ Differential Input Signal 0 VPROC BOP BOP BRP BRP V– VCC Device Output VOUT VOUT(sat) Figure 3. The peaks in the resulting differential signal are used to set the operate, BOP , and release, BRP , switchpoints. Target (Gear) Element Pitch Hall Element 2 South Pole North Pole (Pin n >1 Side) Hall Element 1 Hall IC Pole Piece (Concentrator) Back-Biasing Rare-Earth Pellet Case (Pin 1 Side) Dual-Element Hall Effect Device Figure 2. Relative motion of the target is detected by the dual Hall elements mounted on the Hall IC. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 11 ATS617LSG Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC 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. Superior Performance The ATS617 peak-detecting differential design has several advantages over conventional Hall-effect gear-tooth sensors. The signal-processing techniques used in the ATS617 solve the catastrophic issues that affect the functionality of conventional digital gear-tooth sensors, such as the following: • 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 variation caused by air gap changes is minimized by the self-calibration 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 circuitry 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 achievable 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 immunity 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-element 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