A1642LK-I1-T

A1642LK Two-Wire True Zero-Speed Miniature Differential Peak-Detecting Sensor with Continuous Calibration The A1642 is an optimized Hall effect sensing integrated circuit that provides a user-friendly solution for true zero-speed digital ring-magnet sensing in two-wire applications. This small package can be easily assembled and used in conjunction with a wide variety of target shapes and sizes. The integrated circuit incorporates a dual-element Hall effect sensor and signal processing that switches in response to differential magnetic signals created by ring magnet poles. The circuitry contains a sophisticated digital circuit to reduce system offsets, to calibrate the gain for air-gap–independent switchpoints, and to achieve true zero-speed operation. Signal optimization occurs at power-on through the combination of offset and gain adjust and is maintained throughout the operating time with the use of a running-mode calibration. The running-mode calibration allows immunity to environmental effects such as micro-oscillations of the target or sudden air gap changes. The regulated current output is configured for two-wire applications and the sensor is ideally suited for obtaining speed and duty cycle information in ABS (antilock braking systems). The 1.5 mm spacing between the dual Hall elements is optimized for fine pitch ring-magnet-based configurations. For applications requiring sensing of rotating ferrous gears and targets, refer to the ATS642LSH series of products. The package is lead (Pb) free, with 100% matte tin leadframe plating. Package K, 4-pin SIP 1234 1. VCC 2. No connection 3. Test pin (float or tie to GND) 4. GND Features and Benefits • Running mode calibration for continuous optimization • Single chip IC for high reliability • Internal current regulator for 2-wire operation • Precise duty cycle signal over operating temperature range • Large operating air gaps • Automatic Gain Control (AGC) for air gap independent switchpoints • Automatic Offset Adjustment (AOA) for signal processing optimization • True zero-speed operation • Undervoltage lockout • Wide operating voltage range ABSOLUTE MAXIMUM RATINGS Supply Voltage, VCC .......................................... 28 V Reverse-Supply Voltage, VRCC ........................ –18 V Operating Temperature Ambient, TA,............................... –40ºC to 150ºC Maximum Junction, TJ(max)........................165ºC Storage Temperature, TS .................. –65ºC to 170ºC Use the following complete part numbers when ordering: Part Number A1642LK-I1-T A1642LKTN-I1-T A1642LK-I2-T A1642LKTN-I2-T Packing* Bulk, 500 pieces/bag Tape and reel, 13-inch reel 4000 pieces/reel Bulk, 500 pieces/bag Tape and reel, 13-inch reel 4000 pieces/reel ICC Typical 6.0 Low to 14.0 High mA 7.0 Low to 14.0 High mA *Contact Allegro for additional packing options. A1642LK-DS Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1642LK Two-Wire True Zero-Speed Miniature Differential Peak-Detecting Sensor with Continuous Calibration Functional Block Diagram Hall Amplifier Gain VCC Automatic Offset Control AOA DAC AGC DAC Internal Regulator Gain Control Tracking DAC Peak Hold GND Test Signals Test A1642LK-DS Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 2 A1642LK Two-Wire True Zero-Speed Miniature Differential Peak-Detecting Sensor with Continuous Calibration OPERATING CHARACTERISTICS TA and VCC within specification, unless otherwise noted CHARACTERISTIC Symbol Test Conditions Min. Typ.1 Max. Units ELECTRICAL CHARACTERISTICS Supply Voltage2 Undervoltage Lockout Supply Zener Clamp Voltage Supply Zener Current VCC VCC(UV) VZ IZ ICC(Low) Supply Current ICC(High) Supply Current Ratio Reverse Battery Current Operating; TJ < 165 °C VCC 0 → 5 V and 5 → 0 V ICC = ICC(max) + 3 mA; TA = 25°C Test conditions only; VZ = 28 V A1642LK-I1 A1642LK-I2 A1642LK-I1 A1642LK-I2 4.0 – 28 – 4.0 5.9 12.0 11.8 1.85 – – – – – 6.0 7.0 14.0 14.0 – – 24 4.0 – ICC(max)+ 3 mA 8.0 8.4 16.0 16.8 3.05 –5 V V V mA mA mA mA mA – mA ICC(High)/ Ratio of high current to low current ICC(Low) IRCC VRCC = –18 V POWER-ON STATE CHARACTERISTICS Power-On State3 Power-On Time4 OUTPUT STAGE Output Slew Rate5 dI/dt RLOAD = 100 Ω, CLOAD = 10 pF – 14 – mA/μs POS tPO t > tPO fOP < 100 Hz – – ICC(High) 1 – 2 – ms Continued on the next page. A1642LK-DS Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 3 A1642LK Two-Wire True Zero-Speed Miniature Differential Peak-Detecting Sensor with Continuous Calibration OPERATING CHARACTERISTICS (continued) TA and VCC within specification, unless otherwise noted Characteristic Symbol Test Conditions Min. Typ.1 Max. Units SWITCHPOINT CHARACTERISTICS Operating Speed Analog Signal Bandwidth Operate Point Release Point CALIBRATION Initial Calibration DAC CHARACTERISTICS Allowable User-Induced Differential Offset FUNCTIONAL CHARACTERISTICS6 Operating Signal Range7 Minimum Operating Signal 1Typical 2Maximum fOP BW BOP BRP Equivalent to f – 3 dB Transitioning from ICC(High) to ICC(Low); positive peak referenced; AG < AGMAX Transitioning from ICC(Low) to ICC(High); negative peak referenced; AG < AGMAX Quantity of rising output (current) edges required for accurate edge detection 0 20 – – – 40 120 120 8,000 – – – Hz kHz mV mV CI – – 3 Edge Operating within specification – – ±90 G Sig SigOP(min) Operating within specification Output switching (no missed edges); ΔDC not guaranteed 30 20 – – 1000 – G G 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. 3Please refer to Sensor Operation section, page 11. 4Power-On Time includes the time required to complete the internal automatic offset adjust. The DACs are then ready for peak acquisition. 5dI is the difference between 10% of I CC(Low) and 90% of ICC(High), and dt is time period between those two points. Note: di/dt is dependent upon the value of the bypass capacitor, if one is used. 6Functional characteristics valid only if magnetic offset is within the specified range for Allowable User Induced Differential Offset. 7In order to remain in specification, the magnetic gradient must induce an operating signal greater than the minimum value specified. This includes the effect of target wobble. A1642LK-DS Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 4 A1642LK Two-Wire True Zero-Speed Miniature Differential Peak-Detecting Sensor with Continuous Calibration Characteristic Data Supply Current (High) versus Ambient Temperature (I1 Trim) 16 16 Supply Current (High) versus Supply Voltage (I1 Trim) 15 ICC(HIGH) (mA) 15 Vcc (V) 24 12 4 ICC(HIGH) (mA) 14 14 13 13 TA (°C) -40 25 85 150 12 -50 0 50 TA (°C) 100 150 12 0 5 10 VCC (V) 15 20 25 Supply Current (Low) versus Ambient Temperature (I1 Trim) 8 8 Supply Current (Low) versus Supply Voltage (I1 Trim) 7 Vcc (V) 24 12 4 ICC(LOW) (mA) ICC(LOW) (mA) 7 TA (°C) -40 25 150 6 6 5 5 4 -50 0 50 TA (°C) 4 100 150 0 5 10 VCC (V) 15 20 25 A1642LK-DS Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 5 A1642LK Two-Wire True Zero-Speed Miniature Differential Peak-Detecting Sensor with Continuous Calibration Characteristic Allowable Air Gap Movement Allowable Air Gap Movement from TEAGCAL* 1.2 1.0 ΔTEAGOUT (mm) 0.8 0.6 0.4 0.2 0 -0.2 0 0.2 0.4 0.6 0.8 1.0 ΔTEAGIN (mm) 1.2 1.4 1.6 1.8 *Data based on study performed using spur gear reference target 60-0, and applicable to ring magnet targets with similar magnetic characteristics. The colored area in the chart above shows the region of allowable air gap movement within which the sensor will continue output switching. The output duty cycle is wholly dependent on the target’s magnetic signature across the air gap range of movement, and may not always be within specification throughout the entire operating region (to AG(OPmax)). The axis parameters for the chart are defined in the drawings below. As an example, assume the case where the air gap is allowed to vary from from the nominal installed air gap (TEAGCAL , panel a) within the range defined by an increase of ΔTEAGOUT = 0.35 mm (shown in panel b), and a decrease of ΔTEAGIN = 0.65 mm (shown in panel c). This case is plotted with an “x” in the chart above. For more information on these figures and the calculations used to generate them, please refer to the Applications Note Determining Allowable Air Gap Variation for the ATS642. (a) (b) (c) Sensor TEAGCAL Sensor Sensor TEAG IN TEAG OUT A1642LK-DS Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 6 A1642LK Two-Wire True Zero-Speed Miniature Differential Peak-Detecting Sensor with Continuous Calibration THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information CHARACTERISTIC Package Thermal Resistance Symbol RθJA TEST CONDITIONS* Single-layer PCB with copper limited to solder pads Value 177 Units ºC/W *Additional information is available on the Allegro Web site. 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 20 40 60 VCC(max) Maximum Allowable VCC (V) (RθJA = 177 ºC/W) VCC(min) 80 100 120 140 160 180 Temperature (ºC) Power Dissipation versus Ambient Temperature 900 800 700 Power Dissipation, PD (m W) 600 (R θJ 500 400 300 200 100 0 20 A = 17 7 ºC /W ) 40 60 80 100 120 140 Temperature, TA (°C) 160 180 A1642LK-DS Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 7 A1642LK Two-Wire True Zero-Speed Miniature Differential Peak-Detecting Sensor with Continuous Calibration Functional Description Sensing Technology The single-chip differential Hall effect sensor IC possesses two Hall elements, which sense the magnetic profile of the ring magnet simultaneously, but at different points (spaced at a 1.5 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 compensation 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 compensation circuitry. The Hall transducers and signal processing electronics are integrated on the same silicon substrate, using a proprietary BiCMOS process. Target Profiling shown 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 sensor output switching from high, ICC(High), to low ICC(Low), as the leading edge of a north magnetic pole passes the sensor face. In this configuration, the device output current switches to its low polarity when a north pole is the target feature nearest to the sensor. If the direction of rotation is reversed, then the output polarity inverts. Note that output voltage polarity is dependent on the position of the sense resistor, RSENSE (see figure 4). Target Ring Magnet Representative Differential Magnetic Profile Sensor Electrical Output Profile, IOUT N S N S An operating device is capable of providing digital information that is representative of the magnetic features on a rotating target. The waveform diagram shown in figure 3 presents the automatic translation of the magnetic profile to the digital output signal of the sensor. Output Polarity Figure 3 shows the output polarity for the orientation of target and sensor shown in figure 2. The target direction of rotation Figure 3. Output Profile of a ring magnet target for the polarity indicated in figure 2. VCC VSUPPLY RSENSE Target (Ring Magnet) Hall Element 2 (Pin 4 Side) ICC S N S N Element Pitch Hall Element 1 Hall IC (Pin 1 Side) GND 4 1 VCC 1 VOUT(H) VCC A1642 A1642 GND 4 Figure 1. Relative motion of the target is detected by the dual Hall elements mounted on the Hall IC. VOUT(L) ICC RSENSE Rotating Target Branded Face of Sensor IOUT VOUT(L) VOUT(H) I+ V+ 1 4 V+ Figure 2. This left-to-right (pin 1 to pin 4) direction of target rotation results in a low output signal when a magnetic north pole of the target is nearest the face of the sensor (see figure 3). A right-to-left (pin 4 to pin 1) rotation inverts the output signal polarity. Figure 4: Voltages profiles for high side and low side two-wire sensing. Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 8 A1642LK-DS A1642LK Two-Wire True Zero-Speed Miniature Differential Peak-Detecting Sensor with Continuous Calibration 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). During calibration, the device determines the peak-topeak amplitude of the signal generated by the target. The gain of the sensor is then automatically adjusted. Figure 5 illustrates the effect of this feature. Automatic Offset Adjust (AOA) to compensate for offsets induced by temperature variations over time. Digital Peak Detection The AOA is patented circuitry that automatically compensates for the effects of chip, magnet, and installation offsets. (For capability, see Dynamic Offset Cancellation, in the Operating Characteristics table.) This circuitry is continuously active, including both during calibration mode and running mode, compensating for any offset drift. Continuous operation also allows it A digital DAC tracks the internal analog voltage signal VPROC, and is used for holding the peak value of the internal analog signal. In the example shown in figure 6, the DAC would first track up with the signal and hold the upper peak’s value. When VPROC drops below this peak value by BOP, the device hysteresis, the output would switch and the DAC would begin tracking the signal downward toward the negative VPROC peak. Once the DAC acquires the negative peak, the output will again switch states when VPROC is greater than the peak by the value BRP. At this point, the DAC tracks up again and the cycle repeats. The digital tracking of the differential analog signal allows the sensor to achieve true zero-speed operation. Target Ring Magnet V+ Internal Differential Analog Signal Response, without AGC N S N S V+ AGLarge Internal Differential Analog Signal BOP AGSmall BRP V+ Internal Differential Analog Signal Response, with AGC AGSmall AGLarge I+ Device Output Current Figure 5. Automatic Gain Control (AGC). The AGC function corrects for variances in the air gap. Differences in the air gap affect the magnetic gradient, but AGC prevents that from affecting device performance, as shown in the lowest panel. Figure 6: Peak Detecting Switchpoint Detail A1642LK-DS Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 9 A1642LK Two-Wire True Zero-Speed Miniature Differential Peak-Detecting Sensor with Continuous Calibration Power Supply Protection Assembly Description The device contains an on-chip regulator and can operate over a wide VCC range. For devices that need to 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 Microsystems for information on the circuitry needed for compliance with various EMC specifications. Refer to figure 7 for an example of a basic application circuit. Undervoltage Lockout This sensor is integrally molded into a plastic body that has been optimized for size, ease of assembly, and manufacturability. High operating temperature materials are used in all aspects of construction. Diagnostics 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. ICC levels may not meet datasheet limits when VCC < VCC(min). The regulated current output is configured for two wire applications, requiring one less wire for operation than do switches with the more traditional open-collector output. Additionally, the system designer inherently gains diagnostics because there is always output current flowing, which should be in either of two narrow ranges, shown in figure 8 as ICC(High) and ICC(Low). Any current level not within these ranges indicates a fault condition. If ICC > ICC(High)max, then a short condition exists, and if ICC < ICC(low)min, then an open condition exists. Any value of ICC between the allowed ranges for ICC(High) and ICC(Low) indicates a general fault condition. V+ 1 VCC A1642 CBYP 0.01 µF +mA ICC(High)max ICC(High)min ICC(Low)max Fault Short Pins 2 and 3 floating GND 4 A A Open Range for Valid ICC(HIGH) ECU ICC(Low)min 100 Ω RSENSE Range for Valid ICC(LOW) 0 Figure 7: Typical Application Circuit Figure 8: Diagnostic Characteristics of Supply Current Values A1642LK-DS Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 10 A1642LK Two-Wire True Zero-Speed Miniature Differential Peak-Detecting Sensor with Continuous Calibration SENSOR OPERATION Each operating mode is described in detail below. Power-On AGC is active, and selects the optimal signal gain based on the amplitude of the VPROC signal. Following each adjustment to the AGC DAC, the Offset DAC is also adjusted to ensure the internal analog signal is properly centered. During this mode, the tracking DAC is active and output switching occurs, but the duty cycle is not guaranteed to be within specification. Running Mode After the Initial Calibration period, CI, establishes a signal gain, the device moves to Running mode. During Running mode, the sensor tracks the input signal and gives an output edge for every peak of the signal. AOA remains active to compensate for any offset drift over time. The A1642 incorporates a novel algorithm for adjusting the signal gain during Running mode. This algorithm is designed to optimize the VPROC signal amplitude in instances where the magnetic signal “seen” during the calibration period is not representative of the amplitude of the magnetic signal for the installed sensor air gap (see figure 9). When power (VCC > VCC(Min)) is applied to the device, a short period of time is required to power the various portions of the IC. During this period, the A1642 powers-on in the high current state, ICC(High). After power-on, there are conditions that could induce a change in the output state. Such an event could be caused by thermal transients, but would require a static applied magnetic field, proper signal polarity, and particular direction and magnitude of internal signal drift. Initial Offset Adjust The sensor initially cancels the effects of chip, magnet, and installation offsets. Once offsets have been cancelled, the digital tracking DAC is ready to track the signal and provide output switching. The period of time required for both Power-On and Initial Offset Adjust is defined as the Power-On Time. Calibration Mode The calibration mode allows the sensor to automatically select the proper signal gain and continue to adjust for offsets. The 1 2 3 4 5 BOP Internal Differential Signal, VPROC BOP BRP BRP Sensor Electrical Output, IOUT Figure 9: Operation of Running Mode Gain Adjust. Position 1. The device is initially powered-on. Self-calibration occurs. Position 2. Small amplitude oscillation of the target sends an erroneously small differential signal to the sensor. The amplitude of VPROC is greater than the switching hysteresis (BOP and BRP), and the device output switches. Position 3. The calibration period completes on the third rising output edge, and the device enters Running mode. Position 4. True target rotation occurs and the correct magnetic signal is generated for the installation air gap. The established signal gain is too large for the target’s rotational magnetic signal at the given air gap. Position 5. Running Mode Calibration corrects the signal gain to an optimal level for the installation air gap. A1642LK-DS Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 11 A1642LK Two-Wire True Zero-Speed Miniature Differential Peak-Detecting Sensor with Continuous Calibration 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 Web site.) 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 ΔT = PD × RθJA TJ = TA + ΔT (1) (2) (3) Example: Reliability for VCC at TA = 150°C, package K (I1 trim), using minimum-K PCB Observe the worst-case ratings for the device, specifically: RθJA = 177°C/W, TJ(max) = 165°C, VCC(max) = 24 V, and ICC(max) = 16 mA. Calculate the maximum allowable power level, PD(max). First, invert equation 3: ΔTmax = 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) = ΔTmax ÷ RθJA = 15°C ÷ 177 °C/W = 84.7 mW Finally, invert equation 1 with respect to voltage: VCC(est) = PD(max) ÷ ICC(max) = 84.7 mW ÷ 16 mA = 5.3 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. For example, given common conditions such as: TA= 25°C, VCC = 12 V, ICC = 4 mA, and RθJA = 177 °C/W, then: PD = VCC × ICC = 12 V × 4 mA = 48 mW ΔT = PD × RθJA = 48 mW × 177 °C/W = 8.5°C TJ = TA + ΔT = 25°C + 8.5°C = 33.5°C A worst-case estimate, PD(max), represents the maximum allowable power level (VCC(max), ICC(max)), without exceeding TJ(max), at a selected RθJA and TA. A1642LK-DS Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 12 A1642LK Two-Wire True Zero-Speed Miniature Differential Peak-Detecting Sensor with Continuous Calibration Package K .208 5.28 .203 5.16 D .0591 1.50 NOM C D .0730 1.85 NOM .063 1.60 .059 1.50 B .138 3.51 .133 3.38 .0520 1.32 NOM D E1 .045 1.14 MIN .085 2.16 MAX E2 A .033 0.84 NOM .021 0.53 MAX .600 15.24 .560 14.22 .017 0.44 .014 0.35 1 2 3 4 .019 .014 0.48 0.36 .050 1.27 NOM Dimensions in inches Millimeters in brackets, for reference only Case dimensions exclusive of mold flash or gate burrs Mold flash .010 [0.25] MAX, gate burr .008 [0.20] MAX, dambar protrusion .004 [0.10] MAX Exact case and lead configuration at supplier discretion within limits shown A Dambar removal protrusion (8X) B Ejector mark on opposite side C D Active Area Depth .0165 [0.42] NOM Hall elements E1, E2 placement (element size not to scale) 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 products are not authorized for use as critical components in life-support devices or systems without express written approval. 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. Copyright © 2005 Allegro MicroSystems, Inc. A1642LK-DS Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 13