A1140/41/42/43 Sensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches The A1140, A1141, A1142, and A1143 devices are sensitive, two-wire, unipolar, Hall effect switches that are factory-programmed at end-of-line to optimize magnetic switchpoint accuracy. These devices use a patented high frequency chopper-stabilization technique, produced using the Allegro advanced BiCMOS wafer fabrication process, to achieve magnetic stability and to eliminate offset inherent in single-element devices exposed to harsh application environments. Package LH, 3-pin SOT 1:1 Package UA, 3-pin SIP 1:1 Commonly found in a number of automotive applications, these switches are utilized to sense seat track position, seat belt buckle presence, hood/trunk latching, and shift selector position. Two-wire unipolar switches, such as the A1140/41/42/43 family, are particularly advantageous in price-sensitive applications because they require 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. Any current level not within these ranges indicates a fault condition. The A1140/41/42/43 family of switches also features on-chip transient protection and a Zener clamp to protect against overvoltage conditions on the supply line. The output currents of the A1141 and A1143 switch HIGH in the presence of a south (+) polarity magnetic field of sufficient strength, and switch LOW otherwise, as in the presence of a weak field or a north (-) polarity field. The other two devices in the family (A1140 and A1142) have an opposite output: the currents switch LOW in the presence of a south-polarity magnetic field of sufficient strength, and switch HIGH otherwise. The other differences in the switches are their defined low current levels and magnetic switchpoints. All versions are offered in two package styles. The LH is a SOT-23W, miniature low-profile package for surface-mount applications. The UA is a three-lead ultramini SIP for through-hole mounting. Each package is available in a lead (Pb) free version (suffix, -T) with 100% matte tin plated leadframe. Field-programmable versions also available: A1180, A1181, A1182, and A1183. ABSOLUTE MAXIMUM RATINGS Supply Voltage, VCC .......................................... 28 V Reverse-Supply Voltage, VRCC ........................ -18 V Magnetic Flux Density, B .........................Unlimited Power Dissipation, PD ............................ Graph, p. 5 Operating Temperature Ambient, TA, Range E.................. -40C to 85C Ambient, TA, Range L................ -40C to 150C Maximum Junction, TJ(max)........................165C Storage Temperature, TS .................. -65C to 170C A1140-DS, Rev. 2 Features and Benefits Chopper stabilization Low switchpoint drift over operating temperature range Low sensitivity to stress Factory programmed at end-of-line for optimized switchpoints On-chip protection Supply transient protection Reverse-battery protection On-board voltage regulator 3.5 to 24 V operation Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1140/41/42/43 Sensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches Functional Block Diagram V+ VCC Regulator To All Subcircuits Clock/Logic Amp Sample and Hold Dynamic Offset Cancellation 0.01 uF Low-Pass Filter GND GND Package UA Only Package LH, 3-pin SOT Package UA, 3-pin SIP 3 PTCT NC 1. VCC 2. No connection 3. GND 1 2 1. VCC 2. GND 3. GND 1 2 3 2 A1140-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1140/41/42/43 Sensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches ELECTRICAL CHARACTERISTICS over the operating voltage and temperature ranges, unless otherwise specified Characteristic Supply Voltage1 Symbol Test Conditions Typ. Max. Units 3.5 - 24 V B>BOP for A1140; B<BRP for A1141 2 - 5 mA B>BOP for A1142; B<BRP for A1143 5 -- 6.9 mA B>BOP for A1141, A1143 B<BRP for A1140, A1142 12 -- 17 mA - - -1.2 mA VCC ICC(L) Supply Current ICC(H) Reverse Supply Current Min. IRCC VCC = -18 V Supply Zener Clamp Voltage VZSUPPLY ICC = ICCL(max) + 3 mA; TA = 25C 28 - 40 V Supply Zener Clamp Current3 IZSUPPLY VZSUPPLY = 28 V - - 10 mA Capacitance of the oscilloscope performing the measurement = 20 pF - 36 - mA/s - 200 - kHz CBYPASS = 0.01 F - - 25 s t < ton; VCC slew rate > 25 mV/s - HIGH - - Output Slew Rate4 di/dt Chopping Frequency fC Power-On Time5 ton Power-On State6,7 POS MAGNETIC CHARACTERISTICS over the operating voltage and temperature ranges, unless otherwise specified Characteristic Symbol Operate Point BOP Release Point BRP Hysteresis BHYS Test Conditions A1440, A1442 ICC = ICCL A1441, A1443 ICC = ICCH A1440, A1442 ICC = ICCH A1441, A1443 ICC = ICCL BHYS = BOP - BRP Min. Typ.* Max. Units 50 80 115 G 45 65 110 G 5 15 30 G *Typical data taken at TA = 25 3 A1140-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1140/41/42/43 Sensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches Characteristic Data Supply Current (Low) versus Ambient Temperature at Various Levels of VCC (A1140 and A1141) Supply Current (Low) versus Ambient Temperature at Various Levels of VCC (A1142 and A1143) 10 10 8 8 6 VCC 3.5 V 12.0 V 24.0 V 4 ICCL (mA) ICCL (mA) VCC 2 6 3.5 V 12.0 V 24.0 V 4 2 0 -50 0 50 100 150 0 -50 200 0 Ambient Temperature, TA (C) 50 100 150 200 Ambient Temperature, TA (C) Supply Current (High) versus Ambient Temperature at Various Levels of VCC (A1140, A1141, A1142, and A1143) 20 18 ICCH (mA) VCC 16 3.5 V 12.0 V 24.0 V 14 12 10 -50 0 50 100 150 200 Ambient Temperature, TA (C) Operate Point versus Ambient Temperature at Various Levels of VCC (A1140, A1141, A1142, and A1143) Switchpoint Hysteresis versus Ambient Temperature at Various Levels of VCC (A1140, A1141, A1142, and A1143) 110 10 100 8 VCC 3.5 V 12.0 V 24.0 V 80 70 6 3.5 V 12.0 V 24.0 V 4 2 60 50 -50 VCC BHYS (G) BOP (G) 90 0 50 100 Ambient Temperature, TA (C) 150 200 0 -50 0 50 100 150 200 Ambient Temperature, TA (C) 4 A1140-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1140/41/42/43 Sensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information Characteristic Symbol Test Conditions Package LH, minimum-K PCB (single layer, single-sided with copper limited to solder pads) Package LH, low-K PCB (single layer, double-sided with 0.926 in2 copper area) Package UA, minimum-K PCB (single layer, single-sided with copper limited to solder pads) RJA Maximum Allowable VCC (V) Package Thermal Resistance Value Units 110 C/W 228 C/W 165 C/W Power Derating Curve TJ(max) = 165C; 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) Low-K PCB, Package LH (RJA = 110 C/W) Minimum-K PCB, Package UA (RJA = 165 C/W) Minimum-K PCB, Package LH (RJA = 228 C/W) 20 40 60 80 100 120 VCC(min) 140 160 180 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 Lo (R w-K PC J A = 11 B, P 0 ac Min C/ ka W ge (R imum ) LH KP JA = 165 CB C/ , Pac W) kag eU A Min imu m-K (R P JA = 228 CB, Pa C/W ckag e LH ) 20 40 60 80 100 120 Temperature (C) 140 160 180 5 A1140-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1140/41/42/43 Sensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches Functional Description Operation The output, ICC, of the A1140 and A1142 devices switch low after the magnetic field at the Hall sensor exceeds the operate point threshold, BOP. When the magnetic field is reduced to below the release point threshold, BRP, the device output goes high. The differences between the magnetic operate and release point is called the hysteresis of the device, BHYS. This built- I+ in hysteresis allows clean switching of the output even in the presence of external mechanical vibration and electrical noise. The A1141 and A1143 devices switch with opposite polarity for similar BOP and BRP values, in comparison to the A1140 and A1142 (see figure 1). I+ Switch to High ICC ICC ICC(H) Switch to Low Switch to Low Switch to High ICC(H) ICC(L) BRP BHYS (A) A1140, A1142 B+ B- BRP BOP B- ICC(L) 0 BOP 0 B+ BHYS (B) A1141, A1143 Figure 1. Alternative switching behaviors are available in the A114x device family. On the horizontal axis, the B+ direction indicates increasing south polarity magnetic field strength, and the B- direction indicates decreasing south polarity field strength (including the case of increasing north polarity). 6 A1140-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1140/41/42/43 Sensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches Chopper Stabilization Technique When using Hall-effect technology, a limiting factor for switchpoint accuracy is the small signal voltage developed across the Hall element. This voltage is disproportionally small relative to the offset that can be produced at the output of the Hall sensor. This makes it difficult to process the signal while maintaining an accurate, reliable output over the specified operating temperature and voltage ranges. Chopper stabilization is a unique approach used to minimize Hall offset on the chip. The patented Allegro technique, namely Dynamic Quadrature Offset Cancellation, removes key sources of the output drift induced by thermal and mechanical stresses. This offset reduction technique is based on a signal modulationdemodulation process. The undesired offset signal is separated from the magnetic field-induced signal in the frequency domain, through modulation. The subsequent demodulation acts as a modulation process for the offset, causing the magnetic fieldinduced signal to recover its original spectrum at baseband, while the dc offset becomes a high-frequency signal. The magneticsourced signal then can pass through a low-pass filter, while the modulated dc offset is suppressed. This configuration is illustrated in figure 2. The chopper stabilization technique uses a 200 kHz high frequency clock. For demodulation process, a sample and hold technique is used, where the sampling is performed at twice the chopper frequency (400 kHz). This high-frequency operation allows a greater sampling rate, which results in higher accuracy and faster signal-processing capability. This approach desensitizes the chip to the effects of thermal and mechanical stresses, and produces devices that have extremely stable quiescent Hall output voltages and precise recoverability after temperature cycling. This technique is made possible through the use of a BiCMOS process, which allows the use of low-offset, low-noise amplifiers in combination with high-density logic integration and sample-and-hold circuits. The repeatability of magnetic field-induced switching is affected slightly by a chopper technique. However, the Allegro highfrequency chopping approach minimizes the affect of jitter and makes it imperceptible in most applications. Applications that are more likely to be sensitive to such degradation are those requiring precise sensing of alternating magnetic fields; for example, speed sensing of ring-magnet targets. For such applications, Allegro recommends its digital sensor families with lower sensitivity to jitter. For more information on those devices, contact your Allegro sales representative. Regulator Hall Element Amp Sample and Hold Clock/Logic Low-Pass Filter Figure 2. Chopper stabilization circuit (Dynamic Quadrature Offset Cancellation) 7 A1140-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1140/41/42/43 Sensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches Application Information Typical Application Circuit The A114x family of devices must be protected by an external bypass capacitor, CBYP, connected between the supply, VCC, and the ground, GND, of the device. CBYP reduces both external noise and the noise generated by the chopper-stabilization function. As shown in figure 3, a 0.01 F capacitor is typical. V+ VCC A114x Installation of CBYP must ensure that the traces that connect it to the A114x pins are no greater than 5 mm in length. All high-frequency interferences conducted along the supply lines are passed directly to the load through CBYP, and it serves only to protect the A114x internal circuitry. As a result, the load ECU (electronic control unit) must have sufficient protection, other than CBYP, installed in parallel with the A114x. GND CBYP 0.01 F GND B A A series resistor on the supply side, RS (not shown), in combination with CBYP, creates a filter for EMI pulses. When determining the minimum VCC requirement of the A114x device, the voltage drops across RS and the ECU sense resistor, RSENSE, must be taken into consideration. The typical value for RSENSE is approximately 100 . B A Package UA Only B Maximum separation 5 mm RSENSE ECU Figure 3. Typical application circuit For additional general application information, visit the Allegro Web site at www. allegromicro.com. 8 A1140-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1140/41/42/43 Sensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches 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, 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 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 x IIN (1) T = PD x RJA (2) TJ = TA + T (3) Example: Reliability for VCC at TA = 150C, package UA, using minimum-K PCB. Observe the worst-case ratings for the device, specifically: RJA = 165C/W, TJ(max) = 165C, VCC(max) = 24 V, and ICC(max) = 17 mA. Calculate the maximum allowable power level, PD(max). First, invert equation 3: Tmax = 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) = Tmax / RJA = 15C / 165 C/W = 91 mW Finally, invert equation 1 with respect to voltage: VCC(est) = PD(max) / ICC(max) = 91 mW / 17 mA = 5 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. For example, given common conditions such as: TA= 25C, VCC = 12 V, ICC = 4 mA, and RJA = 140 C/W, then: PD = VCC x ICC = 12 V x 4 mA = 48 mW T = PD x RJA = 48 mW x 140 C/W = 7C TJ = TA + T = 25C + 7C = 32C 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. 9 A1140-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1140/41/42/43 Sensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches Device Qualification Program Contact Allegro for information. EMC (Electromagnetic Compatibility) Requirements Contact your local representative for EMC results. Test Name Reference Specification ESD - Human Body Model AEC-Q100-002 ESD - Machine Model AEC-Q100-003 Conducted Transients ISO 7637-1 Direct RF Injection ISO 11452-7 Bulk Current Injection ISO 11452-4 TEM Cell ISO 11452-3 10 A1140-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1140/41/42/43 Sensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches Product Selection Guide Use the complete part numbers when ordering Part Number A1140ELHLT A1140ELHLT-T A1140EUA A1140EUA-T A1140EUATI A1140EUATI-T A1140LLHLT A1140LLHLT-T A1140LUA - Yes - Yes - Yes - Yes - A1140LUA-T Yes A1140LUATI - A1140LUATI-T A1141ELHLT A1141ELHLT-T A1141EUA Yes - Yes - A1141EUA-T Yes A1141EUATI - A1141EUATI-T A1141LLHLT A1141LLHLT-T A1141LUA A1141LUA-T A1141LUATI A1141LUATI-T Packinga Pb-Free Yes - Yes - Yes - Yes Tape and Reel, 3000 pieces/reel Package Operating Ambient Temperature, TA (C) Output Level in South (+) Fieldb Supply Current at Low Output, ICC(L) (mA) Surface Mount Bulk Bag, 500 pieces/bag -40 to 85 Through Hole Tape and Reel, 2000 pieces/reel Low Tape and Reel, 3000 pieces/reel Surface Mount Bulk Bag, 500 pieces/bag -40 to 150 Through Hole Tape and Reel, 2000 pieces/reel 2 to 5 Tape and Reel, 3000 pieces/reel Surface Mount Bulk Bag, 500 pieces/bag -40 to 85 Through Hole Tape and Reel, 2000 pieces/reel High Tape and Reel, 3000 pieces/reel Surface Mount Bulk Bag, 500 pieces/bag -40 to 150 Through Hole Tape and Reel, 2000 pieces/reel Continued on the next page.... 11 A1140-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1140/41/42/43 Sensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches Continued from the previous page.... Part Number A1142ELHLT A1142ELHLT-T A1142EUA A1142EUA-T A1142EUATI A1142EUATI-T A1142LLHLT A1142LLHLT-T A1142LUA Pb-Free - Yes - Yes - Yes - Yes - A1142LUA-T Yes A1142LUATI - A1142LUATI-T A1143ELHLT A1143ELHLT-T A1143EUA Yes - Yes - A1143EUA-T Yes A1143EUATI - A1143EUATI-T A1143LLHLT A1143LLHLT-T A1143LUA A1143LUA-T A1143LUATI A1143LUATI-T Yes - Yes - Yes - Yes Packinga Tape and Reel, 3000 pieces/reel Package Operating Ambient Temperature, TA (C) Output Level in South (+) Fieldb Supply Current at Low Output, ICC(L) (mA) Surface Mount Bulk Bag, 500 pieces/bag -40 to 85 Through Hole Tape and Reel, 2000 pieces/reel Low Tape and Reel, 3000 pieces/reel Surface Mount Bulk Bag, 500 pieces/bag -40 to 150 Through Hole Tape and Reel, 2000 pieces/reel 5 to 6.9 Tape and Reel, 3000 pieces/reel Surface Mount Bulk Bag, 500 pieces/bag -40 to 85 Through Hole Tape and Reel, 2000 pieces/reel High Tape and Reel, 3000 pieces/reel Surface Mount Bulk Bag, 500 pieces/bag -40 to 150 Through Hole Tape and Reel, 2000 pieces/reel aContact Allegro bSouth for additional packing options. (+) magnetic fields must be of sufficient strength. 12 A1140-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1140/41/42/43 Sensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches Package LH, 3-Pin; (SOT-23W) 3.10 .122 2.90 .114 1.49 .059 NOM 3 8 0 0.28 .011 NOM 0.70 .028 BSC 0.20 .008 0.13 .005 C 0.96 .038 NOM 2.10 .083 1.85 .073 2.40 .094 BSC A 0.25 .010 MIN 3.00 .118 2.70 .106 1.00 .039 BSC 1 2 0.95 .037 BSC 0.25 .010 BSC Seating Plane Gauge Plane 0.50 .020 0.30 .012 1.13 .045 0.87 .034 0.55 .022 REF A Dimensions in millimeters U.S. Customary dimensions (in.) in brackets, for reference only Hall element B Active Area Depth 0.28 [.011] C Fits SC-59A Solder Pad Layout 0.15 .006 0.00 .000 0.95 .037 BSC Package UA, 3-Pin SIP .164 4.17 .159 4.04 45 BSC .0195 0.50 NOM .0805 2.04 NOM .122 3.10 .117 2.97 .062 1.57 .058 1.47 .0565 1.44 NOM 45 BSC B .085 2.16 MAX .640 16.26 .600 15.24 .031 0.79 REF A 1 2 3 .017 0.44 .014 0.35 .019 0.48 .014 0.36 .050 1.27 BSC Dimensions in inches Metric dimensions (mm) in brackets, for reference only A Dambar removal protrusion B Hall element 13 A1140-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1140/41/42/43 Sensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches 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 (c) 2004, 2005 Allegro MicroSystems, Inc. 14 A1140-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com