ATS627LSG True Zero Speed, Low Jitter, High Accuracy Position Sensor IC Description Features and Benefits • Highly accurate in presence of: ▫ Anomalous target geometry (tooth-tooth variation) ▫ Signature teeth or valleys ▫ Target runout • Highly repeatable output edges (low jitter) • True zero-speed operation • Undervoltage lockout • Air gap independent switchpoints • Defined power-on state • High operating temperature • Single-chip sensing IC for high reliability • Enhanced quality through Scan Path and IDDQ measurement • Enhanced EMC performance Package: 4-pin SIP (suffix SG) Not to scale The ATS627 is a true zero-speed gear tooth sensor IC consisting of an optimized Hall IC and rare earth pellet configuration in a single overmolded package. The integrated circuit provides a manufacturer-friendly solution for digital gear tooth sensing applications. This small package can be easily assembled and used in conjunction with gears of various shapes and sizes. The dual-element Hall IC switches in response to differential magnetic signals created by a ferrous target. Digital processing of the analog signal provides zero-speed performance independent of air gap as well as dynamic adaptation of device performance to the typical operating conditions found in automotive applications. High-resolution peak detecting DACs are used to set the adaptive switching thresholds of the device. Bounded tracking and switchpoint hysteresis reduce the negative effects of any anomalies in the magnetic signal associated with the targets used in many automotive applications. This sensor IC system is optimized for engine crank applications that utilize targets that possess signature regions. This device is available in a lead (Pb) free 4-pin SIP package (SG) with a 100% matte tin plated leadframe. Functional Block Diagram VCC Multiplexed Test Signals Analog Regulators – PDAC Hall Amp Offset Adjust Filter VOUT + Digital Regulator AGC NDAC Reference Generator and Lockout Current Limit Synchronous Digital Controller GND ATS627LSG-DS, Rev. 1 TEST True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG Selection Guide Part Number Packing* ATS627LSGTN-T 800 pieces per 13-in. reel *Contact Allegro™ for additional packing options Absolute Maximum Ratings Characteristic Symbol Supply Voltage VCC Output Off Voltage Notes Refer to Power Derating Section VOUTOFF Rating Unit 26.5 V 26.5 V Reverse Supply Voltage VRCC –18 V Reverse Output Voltage VROUT –0.5 V Output Current IOUTSINK 25 mA –40 to 150 ºC TJ(max) 165 ºC Tstg –65 to 170 ºC Operating Ambient Temperature TA Maximum Junction Temperature Storage Temperature L temperature range Pin-out Diagram Terminal List Table 1 2 3 4 Number Name Function 1 VCC 2 VOUT Open drain output 3 TEST Test pin 4 GND Ground Supply voltage Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 2 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG OPERATING CHARACTERISTICS Valid through full operating supply voltage and ambient temperature ranges, using Reference Target 60+2; unless otherwise specified Characteristics Symbol Min. Typ.1 Max. Unit 4.0 – 24 V VCC = 0 → 5 V or 5 → 0 V – 3.6 3.95 V VCC = VRCC(max) – – –10 mA Test Conditions Electrical Characteristics Supply Voltage2 Undervoltage Lockout Reverse Supply Current3 Supply Zener Clamp Voltage Supply Current Test Pin Zener Clamp Voltage4 VCC VCC(UV) IRCC VZsupply Operating, TJ < TJ(max) 28 – – V ICC ICC = ICC(max) + 3 mA, TA = 25ºC – 7 12 mA VZTEST – 6 – V VOUT , IC connected as in figure 9 – High – V VOUT = On (VOUT = low), IOUT = 20 mA 0 – 450 mV Power-On Characteristics Power-On State POS Output Stage Characteristics Low Output Voltage VOUT(SAT) Output Zener Clamp Voltage VZOUTPUT IOUT = 3 mA, TA = 25°C 28 – – V Output Leakage Current IOUT(OFF) VOUT = Off (VOUT = high) – – 10 μA Output Current Limit IOUT(LIM) VOUT = On (VOUT = low), TJ < TJ(max) 25 45 70 mA – 10 – μs – 0.6 2 μs –60 – 60 G – 115 – mV Output Rise Time tr(OUT) VPU = 12 V, RPU = 1.0 kΩ, CLOAD = 4.7 nF , see figure 1 Output Fall Time tf(OUT) VPU = 12 V, RPU = 1.0 kΩ, CLOAD = 4.7 nF, see figure 1 DAC Characteristics Allowable User-Induced Offset5 BDIFFEXT Other Operating Characteristics, with Continuous Update method, bounded for increasing and decreasing AG Running Mode Lockout Enable LOE Running Mode Lockout Release LOR – 220 – mV – 60 – % – % Operate Point BOP % of peak-to-peak VPROC , referenced from PDAC to NDAC, VOUT high → low Release Point BRP % of peak-to-peak VPROC , referenced from PDAC to NDAC, VOUT low → high – 40 f-3dB Cutoff frequency for low pass filter – 20 – kHz 0 – 12 000 rpm Peak-to-peak differential signal 30 – 1200 G Compliant to accuracy specifications, measured from package branded face to target tooth 0.5 – 2.5 mm No missed edges, measured from package branded face to target tooth 0.5 – 3.0 mm – – ±0.4 deg. Bandwidth Operational Speed SROT Performance Characteristics Operational Magnetic Range Air Gap Relative Timing Accuracy, Sequential Mechanical Rising Edges BIN AG ERRRR 0.5 mm ≤ AG ≤ 2.5 mm; constant target speed, Running mode; relative to measurement taken at AG = 1.5 mm 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 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG OPERATING CHARACTERISTICS (continued) Valid through full operating supply voltage and ambient temperature ranges, using Reference Target 60+2; unless otherwise specified Characteristics Symbol Test Conditions Min. Typ.1 Max. Unit Performance Characteristics (continued) Relative Timing Accuracy, Sequential Mechanical Falling Edges ERRFF 0.5 mm ≤ AG ≤ 2.5 mm; constant target speed, Running mode; relative to measurement taken at AG = 1.5 mm – – ±0.4 deg. Relative Timing Accuracy, Signature Mechanical Rising Edge ERRSIGR 0.5 mm ≤ AG ≤ 2.5 mm; constant target speed, Running mode; relative to measurement taken at AG = 1.5 mm – – ±0.4 deg. Relative Timing Accuracy, Signature Mechanical Falling Edge ERRSIGF 0.5 mm ≤ AG ≤ 2.5 mm; constant target speed, Running mode; relative to measurement taken at AG = 1.5 mm – – ±1.5 deg. 0.5 mm ≤ AG ≤ 2.5 mm – – 0.08 deg. See figure 1 – 20 – μs Edge Accuracy – First and Second Output Edges See figure 2 –TTARGET – TTARGET deg. Edge Accuracy – Third through Sixth Output Edges See figure 2 –0.5 x TTARGET – +0.5 x TTARGET deg. Output edge count (see figure 2), BSIG / BSEQ = 1, or no signature tooth encountered – – 6 – Output edge count (see figure 2), signature region encountered during calibration, and BSIG / BSEQ ≠ 1 – 9 – – BSEQ(min) / Total variation over 60 cycles (see figure 3) BSEQ(max) 0.5 – – – BSEQ(n+1) / Single cycle-to-cycle variation (see figure 3) BSEQ(n) 0.6 – – – 0.8 – 1.6 – Relative Repeatability, Sequential Rising and Falling Edges6 Output Propagation Delay Initial Edge TΘE td(OUT) Accuracy7 Full Edge Accuracy Input Magnetic Characteristics Allowable Differential Sequential Signal Variation8 Allowable Signature Amplitude Ratio BSIG / BSEQ One instance per target revolution (see figure 3) 1Typical values are at TA = 25°C and VCC = 12 V. voltage must be adjusted for power dissipation and junction temperature; see Power Derating section. 3Negative current is defined as current coming out of (sourced from) the specified device terminal. 4Sustained voltages beyond the clamp voltage may cause permanent damage to the IC. 5 1 G (gauss) = 0.1 mT (millitesla). 6The repeatability specification is based on statistical evaluation of a sample population, evaluated at 1000 Hz. 7Power-on frequencies ≤ 200 Hz. Higher power-on frequencies may result in a delay of full output accuracy or undetected target edges. 8Excludes effects caused by signature region. 2Maximum Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 4 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG Processed Input Signal, VPROC VPROC(high) VPROC(BOP) td(OUT) td(OUT) VPROC(BRP) VPROC(low) tr(OUT) Time VOUT(high) 90% VOUT Output Signal, VOUT tf(OUT) 10% VOUT VOUT(low) Time Figure 1. Definition of Output Delay Time, td(OUT) , Output Fall Time, tf(OUT) , and Output Rise Time, tr(OUT) . Target Valley Tooth TTARGET TVPROC VPROC VPROC = the processed analog signal of the sinusoidal magnetic input (per channel) TTARGET = period between successive sensed target mechanical edges of the same orientation (either both rising or both falling) Figure 2. Definition of TTARGET Signature Region Sequential Regions Sequential Regions BSEQ(n) BSEQ(n+1) BSIG BSEQ(max) BSEQ(min) Figure 3. Differential signature amplification and sequential signal variation Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 5 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG Characteristic Performance Supply Current (On) versus Temperature 12 12 10 10 Supply Current, ICC (mA) Supply Current, ICC (mA) Supply Current (On) versus Supply Voltage 8 6 TA (°C) -40 4 25 85 2 0 150 0 5 10 15 20 25 8 6 VCC (V) 4 12 4 18 2 24 0 -50 30 -25 0 Supply Voltage, VCC (V) Supply Current (Off) versus Supply Voltage 75 100 125 150 175 12 Supply Current, ICC (mA) Supply Current, ICC (mA) 50 Supply Current (Off) versus Temperature 12 10 8 6 TA (°C) -40 4 25 85 2 150 0 0 5 10 15 20 25 10 8 6 VCC (V) 4 12 4 18 2 0 30 24 -50 -25 0 Supply Voltage, VCC (V) TA (°C) 350 -40 300 25 85 250 150 200 150 100 50 0 0 5 10 15 20 Output Current, IOUT (mA) 50 75 100 125 150 175 25 30 Output Voltage (On) versus Temperature Low Output Voltage, VOUT(SAT) (mV) 450 400 25 Ambient Temperature, TA (°C) Output Voltage (On) versus Output Current Low Output Voltage, VOUT(SAT) (mV) 25 Ambient Temperature, TA (°C) 450 400 IOUT (mA) 10 350 15 300 20 250 25 200 150 100 50 0 -50 -25 0 25 50 75 100 125 150 175 Ambient Temperature, TA (°C) Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 6 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG Output Current (Off) versus Temperature Output Current, IOUT (mA) 5.0 4.0 3.0 2.0 1.0 0 -1.0 VOUT = 28 V -2.0 -3.0 -4.0 -5.0 -50 -25 0 25 50 75 100 125 150 175 Ambient Temperature, TA (°C) 360° Repeatability versus Air Gap 360° Repeatability versus Air Gap Sequential Region, 3 Rising Edges at Each TA Sequential Region, 3 Falling Edges at Each TA 0.30 0.30 0.25 TA = 150°C 0.20 TA = 25°C 0.15 0.10 Specification Limit 0.05 360° Repeatability 6-Sigma, (°) 360° Repeatability 6-Sigma, (°) 0.25 TA = 150°C 0.20 TA = 25°C 0.15 0.10 Specification Limit 0.05 TA = –40°C TA = –40°C 0 0 0.5 1.0 1.5 2.0 2.5 Air Gap, AG (mm) 3.0 3.5 4.0 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Air Gap, AG (mm) Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 7 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG Timing Accuracy versus Operational Speed AG = 0.5 mm; relative to TA = 25°C, SROT = 1000 rpm Signature Feature, Rising Edge Signature Feature, Falling Edge 1.5 Relative Timing Accuracy (°) Relative Timing Accuracy (°) 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 0 500 1000 1500 2000 1.0 0.5 0 -0.5 -1.0 -1.5 2500 0 Operational Speed, SROT (rpm) 1500 2000 2500 Sequential Features, Falling Edge 1.5 Relative Timing Accuracy (°) 1.5 Relative Timing Accuracy (°) 1000 Operational Speed, SROT (rpm) Sequential Features, Rising Edge 1.0 0.5 0 -0.5 -1.0 -1.5 500 0 500 1000 1500 2000 2500 1.0 0.5 0 -0.5 -1.0 -1.5 0 Operational Speed, SROT (rpm) 500 1000 1500 2000 2500 Operational Speed, SROT (rpm) Ambient Temperature, TA (°C) –40 85 25 150 Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 8 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG Timing Accuracy versus Operational Speed AG = 2.5 mm; relative to TA = 25°C, SROT = 1000 rpm Signature Feature, Rising Edge Signature Feature, Falling Edge 1.5 Relative Timing Accuracy (°) Relative Timing Accuracy (°) 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 0 500 1000 1500 2000 1.0 0.5 0 -0.5 -1.0 -1.5 2500 0 Operational Speed, SROT (rpm) 1500 2000 2500 Sequential Features, Falling Edge 1.5 Relative Timing Accuracy (°) 1.5 Relative Timing Accuracy (°) 1000 Operational Speed, SROT (rpm) Sequential Features, Rising Edge 1.0 0.5 0 -0.5 -1.0 -1.5 500 0 500 1000 1500 2000 2500 1.0 0.5 0 -0.5 -1.0 -1.5 0 Operational Speed, SROT (rpm) 500 1000 1500 2000 2500 Operational Speed, SROT (rpm) Ambient Temperature, TA (°C) –40 85 25 150 Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 9 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG Timing Accuracy versus Air Gap TA = 25°C; relative to AG = 1.5 mm, SROT = 1000 rpm Signature Feature, Rising Edge Signature Feature, Falling Edge 1.5 Relative Timing Accuracy (°) Relative Timing Accuracy (°) 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 0 0.5 1.0 1.5 2.0 2.5 1.0 0.5 0 -0.5 -1.0 -1.5 3.0 0 0.5 Air Gap, AG (rpm) 2.0 2.5 3.0 Sequential Features, Falling Edge 1.5 Relative Timing Accuracy (°) 1.5 Relative Timing Accuracy (°) 1.5 Air Gap, AG (rpm) Sequential Features, Rising Edge 1.0 0.5 0 -0.5 -1.0 -1.5 1.0 0 0.5 1.0 1.5 2.0 2.5 3.0 1.0 0.5 0 -0.5 -1.0 -1.5 0 Air Gap, AG (rpm) 0.5 1.0 1.5 2.0 2.5 3.0 Air Gap, AG (rpm) Operational Speed, SROT (rpm) 500 1500 1000 2000 Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 10 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG Timing Accuracy versus Ambient Temperature AG = 0.5 mm; relative to TA = 25°C, SROT = 1000 rpm Signature Feature, Rising Edge Signature Feature, Falling Edge 1.5 Relative Timing Accuracy (°) Relative Timing Accuracy (°) 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 -50 -25 0 25 50 75 100 125 150 1.0 0.5 0 -0.5 -1.0 -1.5 -50 175 -25 0 Ambient Temperature, TA (°C) Sequential Features, Rising Edge 75 100 125 150 175 1.5 Relative Timing Accuracy (°) Relative Timing Accuracy (°) 50 Sequential Features, Falling Edge 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 -50 25 Ambient Temperature, TA (°C) -25 0 25 50 75 100 125 150 175 1.0 0.5 0 -0.5 -1.0 -1.5 -50 -25 0 25 50 75 100 125 150 175 Ambient Temperature, TA (°C) Ambient Temperature, TA (°C) Operational Speed, SROT (rpm) 500 1500 1000 2000 Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 11 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG Timing Accuracy versus Ambient Temperature AG = 2.5 mm; relative to TA = 25°C, SROT = 1000 rpm Signature Feature, Rising Edge Signature Feature, Falling Edge 1.5 Relative Timing Accuracy (°) Relative Timing Accuracy (°) 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 -50 -25 0 25 50 75 100 125 150 1.0 0.5 0 -0.5 -1.0 -1.5 -50 175 -25 0 Ambient Temperature, TA (°C) Sequential Features, Rising Edge 75 100 125 150 175 1.5 Relative Timing Accuracy (°) Relative Timing Accuracy (°) 50 Sequential Features, Falling Edge 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 -50 25 Ambient Temperature, TA (°C) -25 0 25 50 75 100 125 150 175 1.0 0.5 0 -0.5 -1.0 -1.5 -50 -25 0 25 50 75 100 125 150 175 Ambient Temperature, TA (°C) Ambient Temperature, TA (°C) Operational Speed, SROT (rpm) 500 1500 1000 2000 Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 12 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG Timing Accuracy versus Operational Speed TA = 25°C; relative to AG = 1.5 mm, SROT = 1000 rpm Signature Feature, Rising Edge Signature Feature, Falling Edge 1.5 Relative Timing Accuracy (°) Relative Timing Accuracy (°) 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 0 500 1000 1500 2000 1.0 0.5 0 -0.5 -1.0 -1.5 2500 0 500 Operational Speed, SROT (rpm) Sequential Features, Rising Edge 2000 2500 1.5 Relative Timing Accuracy (°) Relative Timing Accuracy (°) 1500 Sequential Features, Falling Edge 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 1000 Operational Speed, SROT (rpm) 0 500 1000 1500 2000 1.0 0.5 0 -0.5 -1.0 -1.5 2500 0 Operational Speed, SROT (rpm) 500 1000 1500 2000 2500 Operational Speed, SROT (rpm) Air Gap, AG (mm) 0.50 1.00 2.25 0.75 1.50 2.50 Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 13 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG Thermal Characteristics may require derating at maximum conditions, see Power Derating section Characteristic Symbol Test Conditions* Single layer PCB, with copper limited to solder pads RθJA Package Thermal Resistance Single layer PCB, with copper limited to solder pads and 3.57 (23.03 cm2) copper area each side in.2 Value Unit 126 ºC/W 84 ºC/W *Additional thermal information available on the Allegro website Maximum Allowable V CC(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 V CC(max) (R θJA = 84 °C/W) (R θJA= 126 °C/W) V CC(min) 20 40 60 80 100 120 140 160 180 Temperature (°C) Power Dissipation, PD (m W) Power Dissipation versus Ambient Temperature 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 800 700 600 500 400 300 200 100 0 RQJA = 84 ºC/W RQJA = 126 ºC/W 20 40 60 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 14 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG Reference Target Characteristics Reference Target 60+2 Test Conditions Typ. Unit 120 mm Outside Diameter Do Outside diameter of target Face Width F Breadth of tooth, with respect to branded face 6 mm Angular Tooth Thickness t Length of tooth, with respect to branded face; measured at Do 3 deg. Signature Region Angular Tooth Thickness 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 – – Material Symbol Key ØDO ht F tV Branded Face of Package Low Carbon Steel SIG Symbol t,t Characteristics Air Gap Signature Region Reference Gear Magnetic Gradient Amplitude With Reference to Air Gap 1200 Pin 4 1000 800 Pin 1 600 400 Branded Face of Package 200 0 0.5 1 1.5 2 2.5 Reference Target 60+2 3 Air Gap (mm) Reference Gear Magnetic Profile Two Tooth-to-Valley Transitions 500 Air Gap 400 (mm) 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 300 Differential B* (G) Peak-to-Peak Differential Magnetic Flux Density, BDIFF (G) 1400 200 100 0 -100 -200 3.00 mm AG -300 0.50 mm AG -400 -500 0 2 4 6 8 10 12 Gear Rotation (°) Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 15 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG Functional Description Sensing Technology The ATS627 contains a single-chip differential Hall-effect sensor IC, a samarium cobalt pellet, and a flat ferrous pole piece (concentrator). As shown in figure 5, the Hall IC supports two Hall elements, which sense the magnetic profile of the ferrous gear target simultaneously, but at different points (spaced at a 2.2 mm pitch), generating a differential internal analog voltage, VPROC, that is processed for precise switching of the digital output signal. The Hall IC is self-calibrating and also possesses a temperature compensated amplifier and offset cancellation circuitry. The built-in 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 compensation circuitry. The Hall transducers and signal processing electronics are integrated on the same silicon substrate, using a proprietary BiCMOS process. Target Profiling During Operation An operating device is capable of providing digital information that is representative of the mechanical features of a rotating gear. The waveform diagram in figure 7 presents the automatic translation of the mechanical profile, through the magnetic profile that it induces, to the digital output signal of the ATS627. No additional optimization is needed and minimal processing circuitry is required. This ease of use reduces design time and incremental assembly costs for most applications. Determining Output Signal Polarity In figure 7 the top panel, labeled Mechanical Position, represents the mechanical features of the target gear and orientation to the device. The bottom panel, labeled Device Output Signal, displays the square waveform corresponding to the digital output signal that results from a rotating gear configured as shown in figure 6, and electrically connected as in figure 9. That direction of rotation (of the gear side adjacent to the package face) is: perpendicular to the leads, across the face of the device, from the pin 1 side to the pin 4 side. This results in the IC output switching from low state to high state as the leading edge of a tooth (a rising mechanical edge, as detected by the IC) passes the package face. In this configuration, the device output switches to its high polarity when a tooth is the target feature nearest to the package. If the direction of rotation is reversed, so that the gear rotates from the pin 4 side to the pin 1 side, then the output polarity inverts. That is, the output signal goes high when a falling edge is detected, and a valley is nearest to the package. Mechanical Position (Target movement pin 1 to pin 4) This tooth sensed earlier This tooth sensed later Target (Gear) Target Magnetic Profile +B Device Orientation to Target Hall Element Pitch Branded Face Target (Gear) Element Pitch Hall Element 2 Dual-Element Hall Effect Device South Pole Back-biasing Magnet North Pole (Pin 4 Side) IC Hall Element 1 Hall IC Pole Piece (Concentrator) Sensor Branded Face Pin 4 Side (Package Top View) Back-Biasing Rare-Earth Pellet Pin 1 Side Device Internal Differential Analog Signal, VPROC Case (Pin 1 Side) Figure 5. Relative motion of the target is detected by the dual Hall elements in the Hall IC. Branded Face of Sensor Rotating Target BOP(#1) BRP(#1) BOP(#2) BRP(#2) Device Internal Switch State On Off On Off Device Output Signal, VOUT Pin 1 Pin 4 Figure 6. This left-to-right (pin 1 to pin 4) direction of target rotation results in a high output state when a tooth of the target gear is nearest the package face (see figure 3). A right-to-left (pin 4 to pin 1) rotation inverts the output signal polarity. Figure 7: The magnetic profile reflects the geometry of the target, allowing the ATS627 to present an accurate digital output response. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 16 ATS627LSG True Zero Speed, Low Jitter, High Accuracy Position Sensor IC Undervoltage Lockout When the supply voltage falls below the undervoltage lockout voltage, VCC(UV) , the device enters Reset, where the output state returns to the Power-On State (POS) until sufficient VCC is supplied. This lockout feature prevents false signals, caused by undervoltage conditions, from propagating to the output of the IC. Power Supply Protection The device contains an on-chip regulator and can operate over a wide VCC range. For devices that must operate from an unregulated power supply, transient protection must be added externally. For applications using a regulated line, EMI/RFI protection may still be required. Contact Allegro™ for information on the circuitry needed for compliance with various EMC specifications. Refer to figure 9 for an example of a basic application circuit. Automatic Gain Control (AGC) This feature allows the device to operate with an optimal internal electrical signal, regardless of the air gap (within the AG specification). At power-on, the device determines the peak-to-peak amplitude of the signal generated by the target. This feature is also active in Running mode, though very conservatively invoked, to optimize the signal amplitude in the scenario where signal amplitude during the initial calibration period is not representative of the Running mode signal. Automatic Offset Adjust (AOA) The AOA circuitry automatically compensates for the effects of chip, magnet, and installation offsets. This circuitry is continuously active, including during both Power-on mode and Running mode, compensating for any offset drift (within the Allowable User Induced Differential Offset). Continuous operation also allows it to compensate for offsets induced by temperature variations over time. This circuitry works with the AGC during calibration to adjust VPROC in the internal range to allow the DACs to acquire the signal peaks. Bounded Update The ATS627 continuously updates its switchpoints based on the actual signal being received from the target. When the output switches, the sensor resets the tracking DACs so that each proper magnetic signal peak can be acquired. To prevent establishing switchpoints on outlier signal maxima, tracking is limited, or bounded, in magnitude. If such limiting were not applied, then anomalous target features, such as bent, broken or misformed teeth, could create significant output accuracy errors (see figure 8). Running Mode Lockout The ATS627 has a Running mode lockout feature to prevent switching in response to small amplitude input signals that are characteristic of vibration signals. The internal logic of the chip interprets small signal amplitudes below a certain level to be the result of target vibration. The output is held to the state present prior to lockout, until the amplitude of the signal returns to normal operational levels. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 17 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG Outlier Bounded limit enforced Pp PDAC Tracking Pp Pp V PRO C NDAC Tracking Np Np Np Figure 8. Operation of Bounded Update method (for illustrative purposes only, values may not be to scale) • Two DACs track the VPROC signal: PDAC tracks positive (high) peaks, and NDAC tracks negative (low) peaks. • The DACs track the VPROC signal until a peak is reached or the bounding limit is reached. Successive Pp and Np values are used to establish the next switchpoint. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 18 ATS627LSG True Zero Speed, Low Jitter, High Accuracy Position Sensor IC Application Information 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 website.) The Package Thermal Resistance, RJA, 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, RJC, is a 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 TJ, at PD. PD = VIN × IIN T = PD × RJA TJ = TA + ΔT (1) (2) Example: Reliability for VCC at TA = 150°C, package SG, using single layer PCB. Observe the worst-case ratings for the device, specifically: RJA = 126°C/W, TJ(max) = 165°C, VCC(absmax) = 24 V, and ICC = 12 mA. Calculate the maximum allowable power level, PD(max). First, invert equation 3: T(max) = 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) = T(max) ÷ RJA = 15°C ÷ 126 °C/W = 119 mW Finally, invert equation 1 with respect to voltage: VCC(est) = PD(max) ÷ ICC = 119 mW ÷ 12 mA = 9.9 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. (3) For example, given common conditions such as: TA= 25°C, VCC = 12 V, ICC = 7 mA, and RJA = 126 °C/W, then: PD = VCC × ICC = 12 V × 7 mA = 84 mW T = PD × RJA = 84 mW × 126 °C/W = 10.6°C TJ = TA + T = 25°C + 10.6°C = 35.6°C A worst-case estimate, PD(max), represents the maximum allowable power level (VCC(max), ICC(max)), without exceeding TJ(max), at a selected RJA and TA. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 19 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG Typical Application VPU VS 1 VCC CBYPASS ATS627 0.1 μF 3 (Recommended) RPU TEST VOUT Output 2 CL GND 4 Figure 9. Basic typical application circuit Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 20 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG Package SG, 4-Pin SIP 5.50±0.05 F 1.10 1.10 F E B 8.00±0.05 LLLLLLL NNN 5.80±0.05 E1 E2 YYWW Branded Face 1.70±0.10 D 4.70±0.10 1 2 3 4 = 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 A 0.60±0.10 Standard Branding Reference View 0.71±0.05 For Reference Only, not for tooling use (reference DWG-9002) Dimensions in millimeters A Dambar removal protrusion (16X) +0.06 0.38 –0.04 B Metallic protrusion, electrically connected to pin 4 and substrate (both sides) C Thermoplastic Molded Lead Bar for alignment during shipment 24.65±0.10 D Branding scale and appearance at supplier discretion 0.40±0.10 15.30±0.10 E Active Area Depth, 0.43 mm F Hall elements (E1, E2), not to scale 1.0 REF A 1.60±0.10 C 1.27±0.10 0.71±0.10 0.71±0.10 5.50±0.10 Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 21 True Zero Speed, Low Jitter, High Accuracy Position Sensor IC ATS627LSG Revision History Revision Revision Date Description of Revision Rev. 1 August 8, 2011 Add tr and tf definition, update derating example Copyright ©2011-2013, Allegro MicroSystems, LLC Allegro MicroSystems, LLC 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’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 information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, LLC assumes no responsibility for its use; nor for any infringement 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 Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 22