ATS675LSE Self-Calibrating TPOS Speed Sensor Optimized for Automotive Cam Sensing Applications Features and Benefits Description ▪ Chopper stabilized; optimized for automotive cam sensing applications ▪ Optimized absolute timing accuracy step size through gradual transition from TPOS to Running Mode ▪ High immunity to signal anomalies resulting from magnetic overshoot and peak-to-peak field variation ▪ Tight timing accuracy over full operating temperature range ▪ True zero-speed operation ▪ Automatic Gain Control circuitry for air gap independent switchpoints ▪ Operation at supply voltages down to 3.3 V ▪ Digital output representing target profile ▪ Undervoltage lockout (UVLO) ▪ Patented Hall IC-magnet system ▪ Increased output fall time for improved radiated emissions performance The ATS675 is the next generation of the Allegro® True Power-On State (TPOS) sensor family, offering improved accuracy compared to prior generations, gradual TPOS to Running Mode adjustment for accuracy-shift reduction, and longer output fall time for improved radiated emissions performance. The ATS675 provides absolute zero-speed performance and TPOS information. The sensor incorporates a single-element Hall IC with an optimized custom magnetic circuit that switches in response to magnetic signals created by a ferromagnetic target. The IC contains a sophisticated digital circuit designed to eliminate the detrimental effects of magnet and system offsets. Signal processing is used to provide device performance at zero target speed, independent of air gap, and which adapts dynamically to the typical operating conditions found in automotive applications, particularly camshaft-sensing applications. High resolution peak-detecting DACs are used to set the adaptive switching thresholds of the device, ensuring high accuracy despite target eccentricity. Internal hysteresis in the thresholds reduces the negative effects of anomalies in the magnetic signal (such as magnetic overshoot) associated with targets used in many automotive applications. The resulting output of the device is a digital representation of the ferromagnetic target profile. The ATS675 also includes a low bandwidth filter that increases the noise immunity and the signal-to-noise ratio of the sensor. Package: 4-pin SIP module (suffix SE) 1 Not to scale 2 3 The device package is lead (Pb) free, with 100% matte tin leadframe plating. 4 Typical Application VS VPU CBYPASS 0.1 μF RPU 1 VCC 3 A ATS675 TEST OUT GND 4 Sensor Output 2 CL A Recommended Figure 1. Operational circuit for the ATS675 ATS675LSE-DS Self-Calibrating TPOS Speed Sensor Optimized for Automotive Cam Sensing Applications ATS675LSE Selection Guide Part Number Output Protocol Packing* ATS675LSETN-LT-T Output low opposite target tooth ATS675LSETN-HT-T Output high opposite target tooth *Contact Allegro for additional packing options 13-in. reel, 450 pieces per reel Absolute Maximum Ratings Characteristic Symbol Notes Rating Units Supply Voltage VCC 28 V Reverse Supply Voltage VRCC –18 V Reverse Supply Current IRCC –50 mA 20 mA –40 to 150 ºC Output Current IOUT(sink) Internal current limiting is intended to protect the device from output short circuits, but is not intended for continuous operation. Operating Ambient Temperature TA Maximum Junction Temperature TJ(max) 165 ºC Tstg –65 to 170 ºC Storage Temperature Range L Thermal Characteristics may require derating at maximum conditions, see application information Characteristic Symbol RθJA Package Thermal Resistance Test Conditions* Value Units 1-layer PCB with copper limited to solder pads 101 ºC/W 2-layer PCB with copper limited to solder pads and 3.57 in.2 of copper area each side 77 ºC/W *Additional thermal information available on the Allegro website Power Dissipation versus Ambient Temperature Power Derating Curve 30 VCC(max) 20 (RQJA = 77 ºC/W) 15 (RQJA = 101 ºC/W) 10 5 0 20 VCC(min) 40 60 80 100 120 Temperature, TA (ºC) 140 160 180 Power Dissipation, PD (mW) Maximum Allowable VCC (V) 25 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 800 700 600 500 400 300 200 100 0 (R QJ A = 77 (R QJ 20 40 60 A =1 01 ºC /W ºC /W ) ) 80 100 120 140 Temperature, TA (°C) 160 180 Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 2 Self-Calibrating TPOS Speed Sensor Optimized for Automotive Cam Sensing Applications ATS675LSE Functional Block Diagram VCC Multiplexed Test Signals NDAC Internal Regulator (Analog) Internal Regulator (Digital) Update Logic Baseline Trim Oscillator Hall Amp TEST +/ – Low Pass Filter Running Mode Threshold Selector OUT PDAC Mode Control DDA +/ – Auto Gain Adjust Temperature Compensation Trim Dynamic Threshold DAC TPOS Trim Current Limit GND TPOS Pin-out Diagram Terminal List 1 2 3 Number Name Function 1 VCC Supply voltage 2 OUT Open drain output 3 TEST Test pin; connection to GND recommended 4 GND Ground 4 Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 3 ATS675LSE Self-Calibrating TPOS Speed Sensor Optimized for Automotive Cam Sensing Applications OPERATING CHARACTERISTICS Valid using reference target 8X, TA ,TJ , and VCC within specification, unless otherwise noted Characteristics Symbol Test Conditions Min. Typ.1 Max. Unit Electrical Characteristics Supply Voltage2 VCC Operating, TJ < TJ(max) 3.3 – 24 V Undervoltage Lockout VCCUV VCC = 0 → 5 V or 5 → 0 V – – 3.3 V Supply Zener Clamp Voltage VZsupply ICC = ICC(max) + 3 mA, TA = 25°C 28 33 40 V Supply Zener Current3 IZsupply VS = 28 V – – 13 mA – 6.5 10 mA – –5 –10 mA – 500 – kHz VCC > VCC(min), fSIG < 200 Hz – – 1 ms IOUT = 10 mA, output in on-state – – 400 mV Supply Current ICC Reverse Battery Current4 IRCC Chopping Frequency VRCC = –18 V fc Power-On Characteristics Power-On Time5 tPO Output Stage Characteristics Output On Voltage VOUT(SAT) IOUT = 15 mA, output in on-state – – 450 mV VZOUT IOUT = 3 mA, TA = 25°C 30 – – V Output Current Limit IOUTLIM Output in on-state 30 50 80 mA Output Leakage Current IOUTOFF VOUT = 24 V, output in off-state – 0.1 10 μA Output Zener Voltage Time6 td 4 kHz sinusoidal signal, falling electrical edge – 22 – μs Output Rise Time tr RPU = 1 kΩ, CL = 4.7 nF, VPU = 5 V – 10.3 – μs Output Fall Time7 tf TA = 25°C, RPU = 1 kΩ, CL = 4.7 nF Output Delay Output Fall Time Variation Over Temperature Range Output Polarity Δtf VOUT VPU = 5 V 5 8 15 μs VPU = 12 V – 15 – μs – ±0.2 – %/°C Maximum variation from TA = 25°C HT device package option Opposite target tooth – High – V Opposite target valley – Low – V LT device package option Opposite target tooth – Low – V Opposite target valley – High – V TPOS functionality guaranteed 0.5 – 3.0 mm Output switching in Running Mode, TPOS function not guaranteed 3.0 – 4.5 mm Performance Characteristics Operational Air Gap Range8 Extended Air Gap Range9 AGTPOS AGEXTMAX ErrRELR Rising mechanical edges after initial calibration, gear speed = 1000 rpm, target eccentricity < 0.1 mm – 0.4 0.8 deg. ErrRELF Falling mechanical edges after initial calibration, gear speed = 1000 rpm, target eccentricity < 0.1 mm – 0.5 1.0 deg. Relative Timing Accuracy10,11 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 4 ATS675LSE Self-Calibrating TPOS Speed Sensor Optimized for Automotive Cam Sensing Applications OPERATING CHARACTERISTICS (continued) Valid using reference target 8X, TA , TJ , and VCC within specification, unless otherwise noted Characteristics Symbol Test Conditions Min. Typ.1 Max. Unit Tooth Speed fSIG Tooth signal frequency, sinusoidal input signal 0 – 8000 Hz Analog Signal Bandwidth BW Equivalent to –3 dB cutoff frequency – 20 – kHz Switchpoint BST % of peak-to-peak, referenced to tooth signal (see figure 4) – 30 – % Internal Hysteresis12 BHYS % of peak-to-peak signal – 10 – % CALI Quantity of mechanical falling edges during which device is in full TPOS Mode – – 4 Edges 1 – 16 Teeth Switchpoint Characteristics Calibration Initial Calibration13 TPO to Running Mode Adjustment Quantity of target teeth after CALI over which CALTPORM TPOS to Running Mode threshold adjustment occurs Signal Characteristics Breduce(G) Reduction in VPROC amplitude from VPROC(high) to lowest peak VPROC(reduce), all specifications within range (see figure 5) – – 15 %pk-pk Breduce(NG) Reduction in VPROC amplitude from VPROC(high) to lowest peak VPROC(reduce); output switches, other specifications may be out of range (see figure 5) – – 25 %pk-pk Maximum Allowable Signal Reduction14 1Typical values are at TA = 25°C and VCC = 12 V. Performance may vary for individual units, within the specified maximum and minimum limits. voltage must be adjusted for power dissipation and junction temperature; see Power Derating section. 3Maximum current limit is equal to I (max) + 3 mA. CC 4Negative current is defined as conventional current coming out of (sourced from) the specified device terminal. 5Power-On Time is the duration from when V CC rises above VCC(min) until a valid output state is realized. 6Output Delay Time is the duration from when a crossing of the magnetic signal switchpoint, B , occurs to when the electrical output signal, V ST OUT , reaches 90% of VOUT(high). 7Characterization data shows 12 V fall time to be 1.5 times longer than 5 V fall time. See figure 2. 8The Operational Air Gap Range is the range of installation air gaps within which the TPOS (True Power-On State) function is guaranteed to correctly detect a tooth when powered-on opposite a tooth and correctly detecting a valley when powered-on opposite a valley, using reference target 8X. 9The Extended Air Gap Range is a range of installation air gaps, larger than AG TPOS, within which the device will accurately detect target features in Running Mode, but TPOS functionality is NOT guaranteed, possibly resulting in undetected target features during Initial Calibration. Relative Timing Accuracy (ErrREL) not guaranteed in Extended Air Gap Range. 10The term mechanical edge refers to a target feature, such as the side of a gear tooth, passing opposite the device. A rising edge is a transition from a valley to a tooth, and a falling edge is a transition from a tooth to a valley. See figure 7. 11Relative Timing Accuracy refers to the difference in accuracy, relative to a 0.5 mm air gap, through the entire Operational Air Gap Range. See figure 7. 12Refer to Functional Description section for a description of Internal Hysteresis. 13Signal frequency, f SIG < 200 Hz. 14Running Mode; 4X target used. The Operational Signal Amplitude, V PROC , is the internal signal generated by the Hall detection circuitry and normalized by Automatic Gain Calibration. 2Maximum Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 5 ATS675LSE Self-Calibrating TPOS Speed Sensor Optimized for Automotive Cam Sensing Applications Signal Processing Characteristics VOUT(high) VOUT(%) tf VOUT (V) VOUT (%) 100 90 10 0 VOUT(low) Figure 2. Output Rise Time and Output Fall Time 100 90 10 0 td tf VPROC(high) BST VPROC tr VPROC(low) Figure 3. Output Delay Time and Output Fall Time Operational Signal Amplitude Switchpoints VPROC(high) VPROC(high) Breduce(G)(max) Signal Reduction Breduce(NG)(max) VPROC BHYS BHYS VPROC(low) Full Signal Processing VPROC(reduce) Reduced Signal Processing VPROC Magnetic Gradient (B) BST Lowest peak VPROC(low) (Baseline) 0 Figure 4. Switchpoint and Internal Hysteresis Figure 5. Maximum Allowable Signal Reduction. Breduce for a given tooth signal is calculated as follows: Breduce = Signal Reduction Operational Signal Amplitude 100% Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 6 Self-Calibrating TPOS Speed Sensor Optimized for Automotive Cam Sensing Applications ATS675LSE Characteristic Performance OutputSupply Fall Time Versusversus Ambient Temperature Current Supply Voltage Supply Current versus Ambient Temperature RPU = 1 kΩ, C L = 4.7 nF 10 16.00 10 14.00 9 9 8 VCC (V) 7 3.3 15.0 24 TA (°C) -40 VPU (V) 0 5 25 12 85 150 8 10.00 tf (us) ICC (mA) 12.00 8.007 6.006 6 4.00 5 5 2.00 4 -50 -25 0 25 50 75 100 TA (°C) 125 150 0.004 0 -50 175 0.3 VOUT(sat) (mV) 300 IOUT (mA) 250 20 15 10 200 150 Edge Position (°) 0.4 350 125 150 TA (°C) -40 0 25 85 150 -0.4 0.5 175 0.4 0.4 0.3 0.3 0.2 TA (°C) -40 0 25 85 150 0.1 0 -0.1 -0.2 1 1.5 2 AG (mm) 2.5 3 3.5 Relative Timing Accuracy versus Speed TA = 25°C, 1.5 mm Air Gap, Relative to 0.5 mm Air Gap Edge Position (°) Edge Position (°) Relative Timing Accuracy versus Air Gap Rising Mechanical Edge, 1000 rpm, Relative to 0.5 mm Air Gap 0.2 Mechanical Edge Falling Rising 0.1 0 -0.1 -0.2 -0.3 -0.4 0.5 30 175 0 -0.3 75 100 TA (°C) 125 25 150 -0.1 -0.2 50 20 100 0.1 50 25 50 15 75 0.2 100 0 10 25 Relative Timing Accuracy versus Air Gap Falling Mechanical Edge, 1000 rpm, Relative to 0.5 mm Air Gap 400 -25 0 V (V) TCC A (°C) Output Voltage (Low) versus Ambient Temperature 0 -50 -25 5 -0.3 1 1.5 2 AG (mm) 2.5 3 3.5 -0.4 0 500 1000 1500 2000 2500 Gear Speed (rpm) Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 7 Self-Calibrating TPOS Speed Sensor Optimized for Automotive Cam Sensing Applications ATS675LSE Reference Target 8x Test Conditions Typ. Units Do Outside diameter of target 120 mm Face Width F Breadth of tooth, with respect to sensor 6 mm Circular Tooth Length t Length of tooth, with respect to sensor; measured at Do 23.6 mm Circular Valley Length tv Length of valley, with respect to sensor; measured at Do 23.6 mm Tooth Whole Depth ht 5 mm – – Outside Diameter Material Symbol CRS 1018 Symbol Key Branded Face of Sensor tV t Characteristic ØDO F ht Air Gap Branded Face of Sensor Reference Target 8X Figure 6. Configuration with Reference Target Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 8 Self-Calibrating TPOS Speed Sensor Optimized for Automotive Cam Sensing Applications ATS675LSE Functional Description Internal Electronics This device contains a self-calibrating Hall effect IC that provides a Hall element, a temperature compensated amplifier, and offset cancellation circuitry. The IC also contains a voltage regulator that provides supply noise rejection over the operating voltage range. The Hall transducers and the electronics are integrated on the same silicon substrate by a proprietary BiCMOS process. Changes in temperature do not greatly affect this device, due to the stable amplifier design and the offset rejection circuitry. by undervoltage conditions from propagating to the output of the sensor. Sensing Technology The ATS675 gear tooth sensor contains a single-chip Hall effect sensor IC, a 4-pin leadframe, and a specially designed rare-earth magnet. The Hall IC supports a chopper stabilized Hall element that measures the magnetic gradient created by the passing of a ferrous object. This is illustrated in figure 7. The difference in the magnetic gradients created by teeth and valleys allows the devices to generate a digital output signal that is representative of the target features. Output After proper power is applied to the device, it is then capable of providing digital information that is representative of the profile of a rotating gear, as illustrated in figure 8. 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. Undervoltage Lockout When the supply voltage falls below the undervoltage lockout level, VCCUV, the device switches to the off-state. The device remains in that state until the voltage level is restored to the VCC operating range. Changes in the target magnetic profile have no effect until voltage is restored. This prevents false signals caused Power Supply Protection The ATS675 contains an on-chip regulator and can operate over a wide range of supply voltage levels. For applications using an unregulated power supply, transient protection may be added externally. For applications using a regulated supply line, EMI and RFI protection may still be required. Contact Allegro for information on EMC specification compliance. Output Polarity With the LT device option, the polarity of the output is low when the Hall element is opposite a target tooth, and high when opposite a target valley. The output polarity is opposite in the HT option.. This is illustrated in figure 8. TPOS (True Power-On State) Operation Under specified operating conditions, the ATS675 is guaranteed Target Mechanical Profile Target (Gear) Target Magnetic Profile Low-B field Hall element Leadframe High-B field Hall IC North Pole Back-Biasing magnet Plastic Pole piece (Concentrator) South Pole Tooth Valley |B| BIN Sensor Output Electrical Profiles 0 V+ VOUT LT device option Switch State On Off On Off On Off On Off Off On Off On Off On Off On Sensor Device (A) (B) V+ HT device option VOUT Switch State Figure 7. Application cross-section: (A) target tooth opposite device, and (B) target valley opposite device Figure 8. Sensor output polarity and switch state (with device connected as shown in figure 1): with LT option, output is low when a target tooth is opposite the Hall element (device on), and high when a target valley is opposite (device off)—polarity response inverts with the HT option. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 9 ATS675LSE Self-Calibrating TPOS Speed Sensor Optimized for Automotive Cam Sensing Applications to attain the specified output voltage polarity at power-on, in relation to the target feature nearest the device at that time. The TPOS switchpoint is programmed by Allegro to the datasheet specifications. ing accuracy step size during startup conditions. A single large jump in edge position is not allowed; instead, any change in edge position from TPOS to Running Mode is spread over several output transitions. Start-Up Detection The ATS675 provides an output polarity transition at the first target mechanical edge that is opposite the device after power-on. Switchpoints The Running Mode switchpoints in the ATS675 are established dynamically as a percentage of the amplitude of the signal, VPROC , after normalization with AGC. Two DACs track the peaks of VPROC. Calibration The Automatic Gain Calibration (AGC) feature is implemented by a unique patented self-calibrating circuitry. After each poweron, the device measures the peak-to-peak magnetic signal. The gain of the sensor is then adjusted, keeping the internal signal, VPROC , at a constant amplitude throughout the air gap range of the device. This feature ensures that operational characteristics are isolated from the effects of changes in effective air gap. The Initial Calibration process allows the peak detecting DACs to properly acquire the magnetic signal, so that a Running Mode switchpoint can be accurately computed. TPOS to Running Mode After the Initial Calibration process is completed (CALI), the device transitions to Running Mode. As shown in figure 9, the device dynamically adjusts the relative edge position from the TPOS edge location to the Running Mode location over several target teeth (CTPORM), significantly reducing the maximum tim- TPOS Threshold 0n 0ff 0ff 0n Figure 9. Startup calibration order Peak and Valley DAC Update The peak and valley DACs have an algorithm that allows tracking of drift over temperature changes, but provides immunity to target particularities, such as small mechanical valleys. Running Mode BST VPROC LT option Switch State VOUT HT option Switch State VOUT CALTPOSRM Internal Hysteresis The Internal Hysteresis, BHYS , provides high performance over various air gaps while maintaining immunity to false switching on noise, vibration, backlash, or other transient events. Figure 10 demonstrates the function of this hysteresis when switching on an anomalous peak. BST BHYS BHYS VPROC Power-on CALI The switching threshold is established at a fixed percentage of the values held in the two DACs. The ATS675 uses a single switching threshold (operate and release points identical) with internal hysteresis. LT option Switch State VOUT HT option Switch State VOUT 0n 0ff 0ff 0n Figure 10. Output switching can accommodate an anomalous peak, such as the middle peak in this figure, by using the Internal Hysteresis value. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 10 Self-Calibrating TPOS Speed Sensor Optimized for Automotive Cam Sensing Applications ATS675LSE Sensor and Target Evaluation A pair of curves can be derived from this map data, and be used to describe the tooth and valley magnetic field strength, B, versus the size of the air gap, AG. This allows determination of the minimum amount of magnetic flux density that guarantees operation of the sensor, so the system designer can determine the maximum allowable AG for the sensor and target system. One can also determine the TPOS air gap capabilities of the sensor by comparing the minimum tooth signal to the maximum valley signal. Magnetic Profile In order to establish the proper operating specification for a particular sensor device and target system, a systematic evaluation of the magnetic circuit should be performed. The first step is the generation of a magnetic map of the target. By using a calibrated device, a magnetic profile of the system is made. Figure 11 is a magnetic map of the 8X reference target. Magnetic Map, Reference Target 8X with SE Package 1600 1400 Flux Density, B (G) 1200 1000 800 600 400 200 0 0 60 120 180 240 300 360 Target Rotation (°) Air Gap Versus Magnetic Field, Reference Target 8X with SE Package 1300 1200 1100 Flux Density, B (G) 1000 900 800 700 600 500 Tooth 400 Valley 300 200 100 0 0 1.0 2.0 3.0 4.0 5.0 6.0 AG (mm) Figure 11. Magnetic Data for the 8X Reference Target and SE package. Flux density measurements are relative to the baseline magnetic field. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 11 ATS675LSE Self-Calibrating TPOS Speed Sensor Optimized for Automotive Cam Sensing Applications 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, RθJA, 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, RθJC, is relatively small component of RθJA. Ambient air temperature, TA, and air motion are significant external factors, damped by overmolding. The effect of varying power levels (Power Dissipation, PD), can be estimated. The following formulas represent the fundamental relationships used to estimate TJ, at PD. PD = VIN × IIN (1) ΔT = PD × RθJA (2) TJ = TA + ΔT (3) For example, given common conditions such as: TA= 25°C, VCC = 12 V, ICC = 7 mA, and RθJA = 77 °C/W, then: Example: Reliability for VCC at TA = 150°C. Observe the worst-case ratings for the device, specifically: RθJA = 101 °C/W, TJ(max) = 165°C, VCC(max) = 24 V, and ICC(max) = 10 mA. Calculate the maximum allowable power level, PD(max). First, invert equation 3: ΔT(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) = ΔT(max) ÷ RθJA = 15°C ÷ 101 °C/W = 148.5 mW Finally, invert equation 1 with respect to voltage: VCC(est) = PD(max) ÷ ICC(max) = 148.5 mW ÷ 10 mA = 14.9 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 RθJA. If VCC(est) ≥ VCC(max), then operation between VCC(est) and VCC(max) is reliable under these conditions. PD = VCC × ICC = 12 V × 7 mA = 84 mW ΔT = PD × RθJA = 84 mW × 77 °C/W = 6.5°C TJ = TA + ΔT = 25°C + 6.5°C = 31.5°C A worst-case estimate, PD(max), represents the maximum allowable power level, without exceeding TJ(max), at a selected RθJA and TA. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 12 Self-Calibrating TPOS Speed Sensor Optimized for Automotive Cam Sensing Applications ATS675LSE Package SE 4-Pin SIP Module 1.5 7.00 C 10.00 1.5 B 3.3 E 1.3 0.9 5.7 A 4.9 6.2 0.38 24.65 11.6 1 2 3 All dimensions nominal, not for tooling use Dimensions in millimeters Exact case and lead configuration at supplier discretion within limits shown 4 A Dambar removal protrusion (16X) 2.0 0.6 B Metallic protrusion, electrically connected to pin 4 and substrate (both sides) C Active Area Depth, 0.43 mm D Thermoplastic Molded Lead Bar for alignment during shipment E Hall element (not to scale) A D 1.6 1.27 0.7 0.7 5.5 Copyright ©2008, Allegro MicroSystems, Inc. The products described herein are manufactured under one or more of the following U.S. patents: 5,045,920; 5,264,783; 5,442,283; 5,389,889; 5,581,179; 5,517,112; 5,619,137; 5,621,319; 5,650,719; 5,686,894; 5,694,038; 5,729,130; 5,917,320; and other patents pending. Allegro MicroSystems, Inc. reserves the right to make, from time to time, such 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, Inc. 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, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 13