ATS617LSGTN-T

ATS617LSG Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC Features and Benefits Description ▪ 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 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. Package: 4-pin SIP (suffix SG) The ATS617 is ideal for use in systems that gather speed, position, and timing information using gear-tooth-based Not to scale Continued on the next page… Functional Block Diagram VCC RS Voltage Regulator Power-On Logic UVLO Tooth and Valley Comparator VOUT Hall Amp Gain Track and Hold Current Limit Reference Generator Hall Amp Track and Hold GND TEST (Recommended) 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 edgedetection, 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 Symbol Notes Unit Supply Voltage VCC 26.5 V Reverse Supply Voltage VRCC –18 V Output Off Voltage See Power Derating section Rating VOUTOFF 24 V Continuous Output Current IOUT 25 mA Reverse Output Current IROUT 50 mA –40 to 150 ºC TJ(max) 165 ºC Tstg –65 to 170 ºC Operating Ambient Temperature TA Maximum Junction Temperature Storage Temperature Range L Pin-out Diagram Terminal List 1 2 3 4 Number Name Function 1 VCC Device supply 2 VOUT Device output 3 Test Tie to GND, or float 4 GND Device ground Allegro MicroSystems, LLC 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 Symbol Test Condition Min. Typ.1 Max. Unit 4.5 – 24 V – 60 72 Ω – 3.7 – V – 100 400 mV Electrical Characteristics Supply Voltage2 VCC Supply Protection Resistor RS Undervoltage Lockout Threshold Output On Voltage VCC(UV) Operating, TJ < 165C VCC = 0 → 5 V; VCC = 5 → 0 V VOUT(SAT) IOUT = 15 mA, output on Supply Zener Clamp Voltage VZsupply ICC = 15 mA, TA = 25°C 28 – – V Output Zener Clamp Voltage VZoutput IOUT = 3 mA, TA = 25°C 30 – – V Supply Zener Current IZsupply VS = 28 V – – 15 mA Output Zener Current IZoutput VOUT = 30 V – – 3 mA Output Current Limit IOUTM VOUT = 12 V 25 45 55 mA VOUT = 24 V, output off – – 15 μA Output Leakage Current IOUTOFF Supply Current ICC VCC > VCC(min) 3 6 12 mA Power-On Time tPO VCC > 5 V – 80 500 μs Power-On State POS VCC = 0 → 5 V – High – V RPU = 2 kΩ, CL = 4.7 nF, 10% to 90% – 21 – μs 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 Allegro reference target 60+2 operating at or above Minimum Operating Speed 0.4 – 2.5 mm Operation at or above Minimum Operating Speed 60 – – G – 15 – kHz 10 – – rpm Output Rise Time3 tr Output Fall Time tf Performance Characteristics Operating Air Gap Range Operating Magnetic Flux Density Differential4 AG BAG(p-p) Analog Signal Bandwidth BW Minimum Operating Speed SOP Allegro 60+2 reference target Continued on the next page… Allegro MicroSystems, LLC 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 Symbol Test Condition Min. Typ.1 Max. Unit Initial Calibration Cycle5 ncal Output edges before calibration is completed, at fsig < 100 Hz – 1 – edge Calibration Mode Disable ndis 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. Output switching only; may not meet data sheet specifications – – ±50 G Characteristic Performance Characteristics (continued) Allowable User Induced Differential Offset4 ∆BApp Switching Hysteresis, Start-up VSWHYS(su) – 190 – mV Switching Hysteresis, Running Mode VSWHYS(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. 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. 2 Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 4 Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC ATS617LSG Reference Target (Gear) Information REFERENCE TARGET 60+2 SymCharacteristics bol Outside Diameter Do Typ. Units 120 mm Breadth of tooth, with respect to branded face 6 mm t Length of tooth, with respect to branded face; measured at Do 3 deg. tSIG Length of signature tooth, with respect to branded face; measured at Do 15 deg. Angular Valley Thickness tv Length of valley, with respect to branded face; measured at Do 3 deg. Tooth Whole Depth ht 3 mm – – Face Width Angular Tooth Thickness Signature Region Angular Tooth Thickness Material F Test Conditions Outside diameter of target Low Carbon Steel Symbol Key t Do tSIG ht F tv Air Gap 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, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 5 Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC ATS617LSG Characteristic Data Supply Current (On) versus Supply Voltage Supply Current (On) versus Ambient Temperature 12 12 11 11 10 9 TA (°C) –40 25 85 150 8 7 6 5 ICC (mA) ICC (mA) 10 VCC (V) 8 4.5 12 18 24 7 6 5 4 4 3 0 5 10 15 VCC (V) 20 25 3 –50 30 50 100 150 200 Supply Current (Off) versus Ambient Temperature 12 11 11 10 10 9 TA (°C) –40 25 85 150 8 7 6 5 ICC (mA) 12 9 VCC (V) 8 4.5 12 18 24 7 6 5 4 4 3 0 TA (°C) Supply Current (Off) versus Supply Voltage ICC (mA) 9 0 5 10 15 VCC (V) 20 25 30 3 –50 0 50 100 150 200 TA (°C) Continued on the next page. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 6 Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC ATS617LSG Output Voltage (On) versus Ambient Temperature Output Voltage (On) versus Output Current 400 300 IOUT (mA) 5 10 15 20 200 100 0 –50 VSAT(ON) (mV) VSAT(ON) (mV) 400 300 100 0 0 50 100 150 TA (°C) –40 25 85 150 200 200 0 5 10 TA (°C) Output Leakage Current (Off) versus Ambient Temperature 25 15 VOUT (V) 10 2.5 5 7.5 10 5 IOUTOFF (μA) IOUTOFF (μA) 20 Output Leakage Current (Off) versus Output Voltage 15 0 –50 15 IOUT (mA) 10 TA (°C) –40 25 85 150 5 0 0 50 100 TA (°C) 150 200 0 2.5 5 7.5 10 12.5 VOUT (V) Continued on the next page. Allegro MicroSystems, LLC 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 TA = 25°C 1.5 1.0 1.0 1.0 0.5 0 -0.5 -1.0 Edge Position (°) 1.5 Edge Position (°) Edge Position (°) 1.5 -1.5 0.5 0 -0.5 -1.0 -1.5 0 0.5 1.0 1.5 Speed (krpm) 2.0 2.5 -1.0 0.5 1.0 1.5 Speed (krpm) 2.0 2.5 0 1.0 0 -0.5 -1.0 Edge Position (°) 1.0 Edge Position (°) 1.0 0.5 0.5 0 -0.5 -1.0 -1.5 1.0 1.5 Speed (krpm) 2.0 2.5 0.5 1.0 1.5 Speed (krpm) 2.0 2.5 0 1.0 Edge Position (°) 1.0 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 0.5 1.0 1.5 Speed (krpm) 2.0 2.5 0 1.0 -1.5 Edge Position (°) 1.0 Edge Position (°) 1.0 -1.0 0.5 0 -0.5 -1.0 -1.5 1.0 1.5 Speed (krpm) 2.0 2.5 Air Gap (mm) 1.0 1.5 Speed (krpm) 2.0 2.5 Falling Edge 1.5 0.5 0.5 Falling Edge -0.5 2.5 -1.0 1.5 0 2.0 0 -0.5 -1.5 0 Falling Edge 0.5 1.0 1.5 Speed (krpm) 0.5 1.5 0 0.5 Rising Edge 1.5 -1.5 2.5 -1.0 Rising Edge -1.0 2.0 0 -0.5 1.5 -0.5 2.5 -1.5 0 Rising Edge 0 2.0 0.5 1.5 0.5 1.0 1.5 Speed (krpm) Falling Edge 1.5 0.5 0.5 Falling Edge 1.5 0 Edge Position (°) 0 -0.5 1.5 -1.5 Edge Position (°) 0.5 -1.5 0 Falling Edge Edge Position (°) Sequential Region Rising Edge Rising Edge Rising Edge Signature Region TA = 150°C 0.5 0 -0.5 -1.0 -1.5 0 0.5 0.5 1.0 1.5 Speed (krpm) 1.0 2.0 1.5 2.5 2.2 0 0.5 1.0 1.5 Speed (krpm) 2.5 Continued on the next page. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 8 Dynamic, Self-Calibrating, Peak-Detecting, Differential Hall Effect Gear Tooth Sensor IC ATS617LSG Edge Position versus Air Gap through Target Speed Range Speed = 10 rpm Speed = 500 rpm 1.5 1.0 1.0 1.0 0.5 0 -0.5 -1.0 Edge Position (°) 1.5 Edge Position (°) Edge Position (°) 1.5 -1.5 0.5 0 -0.5 -1.0 -1.5 0 1.0 2.0 Air Gap (mm) 3.0 -1.0 1.0 2.0 Air Gap (mm) 3.0 0 1.0 0 -0.5 -1.0 Edge Position (°) 1.0 Edge Position (°) 1.0 0.5 0.5 0 -0.5 -1.0 -1.5 3.0 0.5 0 -0.5 -1.0 -1.5 0 1.0 2.0 Air Gap (mm) 3.0 0 1.0 1.0 -0.5 -1.0 -1.5 Edge Position (°) 1.0 Edge Position (°) 1.5 0 0.5 0 -0.5 -1.0 -1.5 1.0 2.0 Air Gap (mm) 3.0 0.5 0 -0.5 -1.0 -1.5 0 1.0 2.0 Air Gap (mm) 3.0 0 1.0 1.0 -0.5 -1.0 -1.5 Edge Position (°) 1.0 Edge Position (°) 1.5 0 0.5 0 -0.5 -1.0 -1.5 1.0 2.0 Air Gap (mm) 3.0 3.0 Falling Edge 1.5 0 1.0 2.0 Air Gap (mm) Falling Edge Falling Edge 1.5 0.5 3.0 Rising Edge 1.5 0 1.0 2.0 Air Gap (mm) Rising Edge Rising Edge 1.5 0.5 3.0 Falling Edge 1.5 1.0 2.0 Air Gap (mm) 1.0 2.0 Air Gap (mm) Falling Edge 1.5 0 Edge Position (°) 0 -0.5 1.5 -1.5 Edge Position (°) 0.5 -1.5 0 Falling Edge Edge Position (°) Sequential Region Rising Edge Rising Edge Rising Edge Signature Region Speed = 2000 rpm 0.5 0 -0.5 -1.0 -1.5 0 Ambient Temperature (°C) 1.0 2.0 Air Gap (mm) -40 3.0 25 0 85 1.0 2.0 Air Gap (mm) 3.0 150 Allegro MicroSystems, LLC 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 Symbol Test Conditions* Single-sided PCB with copper limited to solder pads RθJA Package Thermal Resistance in.2 Two-sided PCB with copper limited to solder pads and 3.57 (23.03 cm2) of copper area each side, connected to GND pin Value Units 126 ºC/W 84 ºC/W Maximum Allowable VCC (V) *Additional information is available on the Allegro website. Power Derating Curve TJ(max) = 165ºC; ICC = ICC(max) 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) (RQJA = 84 ºC/W) (RQJA = 126 ºC/W) VCC(min) 20 40 60 80 100 120 140 160 180 Power Dissipation, PD (m W) Temperature (ºC) Maximum Power Dissipation, PD(max) TJ(max) = 165ºC; VCC = VCC(max); ICC = ICC(max) 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 800 700 600 500 400 300 200 100 0 (R θJ (R θJ 20 40 60 A =1 26 ºC A = /W 84 ºC /W ) ) 80 100 120 Temperature (°C) 140 160 180 Allegro MicroSystems, LLC 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 Target (Gear) Element Pitch Hall Element 2 Dual-Element Hall Effect Device 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) Figure 2. Relative motion of the target is detected by the dual Hall elements mounted on the Hall IC. 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. Allegro MicroSystems, LLC 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 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: 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. • 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. Figure 4. Affect of varying valley widths on single-element circuits. • 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