A1184 Standard Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall-Effect Switches Package LH, 3-pin SOT 3 1. VCC 2. No connection 3. GND NC 1 2 Package UA, 3-pin SIP 1. VCC 2. GND 3. GND 1 2 3 The A1184 device is a standard, two-wire, unipolar, Hall effect switches. The operate point, BOP, can be field-programmed, after final packaging of the sensor and placement into the application. This advanced feature allows the optimization of the sensor switching performance, by effectively accounting for variations caused by mounting tolerances for the device and the target magnet. This family of devices are produced on the Allegro MicroSystems advanced BiCMOS wafer fabrication process, which implements a patented, high-frequency, chopper-stabilization technique that achieves magnetic stability and eliminates the offsets that are inherent in single-element devices exposed to harsh application environments. Commonly found in a number of automotive applications, the A1184 is utilized to sense: seat track position, seat belt buckle presence, hood/ trunk latching, and shift selector position. Two-wire unipolar switches are particularly advantageous in price-sensitive applications, because they require one less wire than the more traditional open-collector output switches. Additionally, the system designer gains inherent diagnostics because output current normally flows in either of two narrowly-specified ranges. Any output current level outside of these two ranges is a fault condition. The A1184 also features on-chip transient protection, and a Zener clamp to protect against overvoltage conditions on the supply line. The output current of the A1184 switches HIGH in the presence of a south polarity magnetic field of sufficient strength; and switches LOW otherwise, including when there is no significant magnetic field present. ABSOLUTE MAXIMUM RATINGS Supply Voltage, VCC .......................................... 28 V Reverse-Supply Voltage, VRCC ........................ –18 V Magnetic Flux Density, B .........................Unlimited Operating Temperature Ambient, TA, Range E.................. –40ºC to 85ºC Ambient, TA, Range L................ –40ºC to 150ºC Maximum Junction, TJ(max)........................165ºC Storage Temperature, TS .................. –65ºC to 170ºC Both devices are offered in two package styles: LH, a SOT-23W miniature lowprofile package for surface-mount applications, and UA, a three-lead ultramini Single Inline Package (SIP) for through-hole mounting. Each package is available in a lead (Pb) free version (suffix, –T) with 100% matte tin plated leadframe. Factory-programmed versions are also available. Refer to: A1140, A1141, A1142, A1143, A1145, and A1146. Features and Benefits Chopper stabilization Low switchpoint drift over operating temperature range Low stress sensitivity Field-programmable for optimized switchpoints A1184-DS, Rev. 2 On-chip protection Supply transient protection Reverse-battery protection On-board voltage regulator 3.5 V to 24 V operation Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1184 Standard Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switch Product Selection Guide Part Number Pbfree A1184ELHLT3 – A1184ELHLT-T Yes A1184EUA Yes A1184LLHLT – A1184LUA A1184LUA-T Mounting 7-in. reel, 3000 pieces/reel Surface mount Ambient, TA (°C) Output South (+) Field2 Supply Current at Low Output, ICC(L) (mA) High 5 to 6.9 –40 to 85 – A1184EUA-T A1184LLHLT-T Packing1 Bulk, 500 pieces/bag 4-pin SIP through hole 7-in. reel, 3000 pieces/reel Yes Surface mount –40 to 150 – Bulk, 500 pieces/bag Yes 4-pin SIP through hole aContact bSouth Allegro for additional packing options. (+) magnetic fields must be of sufficient strength. cThese variants are in production but have been determined to be NOT FOR NEW DESIGN. This classification indicates that sale of this device is currently restricted to existing customer applications. The device should not be purchased for new design applications because obsolescence in the near future is probable. Samples are no longer available. Status date change May 2, 2005. Functional Block Diagram V+ VCC Program/Lock Programming Logic Offset Regulator Clock/Logic Amp Sample and Hold Dynamic Offset Cancellation 0.01 uF Low-Pass Filter GND GND Package UA Only 2 A1184-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1184 Standard Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switch ELECTRICAL CHARACTERISTICS over the operating voltage and temperature range, unless otherwise specified Characteristic Symbol Supply Voltage1 Supply Current2 Test Conditions Min. Typ. Max. Units 3.5 – 24 V VCC Device powered on ICC(L) B <BRP 5 – 6.9 mA ICC(H) B >BOP 12 – 17 mA Supply Zener Clamp Voltage VZ(supply) ICC = ICC(L)(max) + 3 mA; TA = 25°C 28 – 40 V Supply Zener Clamp Current3 IZ(supply) VZ(supply) = 28 V – – 9.9 mA Reverse Supply Current IRCC VRCC = –18 V – – –1.6 mA Output Slew Rate4 di/dt No bypass capacitor; capacitance of the oscilloscope performing the measurement = 20 pF – 36 – mA/μs – 200 – kHz After factory trimming; with and without bypass capacitor (CBYP = 0.01 μF) – – 25 μs ton ≤ ton(max); VCC slew rate ≥ 25 mV/μs – HIGH – – Chopping Frequency fC Power-On Time5 ton Power-On State6,7 POS 1V CC represents 2Relative values the generated voltage between the VCC pin and the GND pin. of B use the algebraic convention, where positive values indicate south magnetic polarity, and negative values indicate north magnetic polarity; therefore greater B values indicate a stronger south polarity field (or a weaker north polarity field, if present). 3I ZSUPPLY(max) = ICCL(max) + 3 mA. 4Measured without bypass capacitor between VCC and GND. Use of a bypass capacitor results in slower current change. 5Measured with and without bypass capacitor of 0.01 μF. Adding a larger bypass capacitor causes longer Power-On Time. 6POS is defined as true only with a V CC slew rate of 25 mV / μs or greater. Operation with a VCC slew rate less than 25 mV / μs can permanently harm device performance. 7POS is undefined for t > t or B on RP < B < BOP . MAGNETIC CHARACTERISTICS1 over the operating voltage and temperature range, unless otherwise specified Characteristic Symbol Programmable Operate Point Range BOPrange Initial Operate Point Range Switchpoint Step Size2 Number of Programming Bits Min. Typ. Max. Units ICC = ICC(H) 300 – 600 G BOPinit VCC = 12 V – 262 300 G BRES VCC = 5 V, TA = 25°C 8 16 24 G Switchpoint setting – 5 – Bit Programming locking – 1 – Bit – – ±20 G 5 15 30 G – Temperature Drift of BOP ΔBOP Hysteresis BHYS Test Conditions BHYS = BOP – BRP 1Relative values of B use the algebraic convention, where positive values indicate south magnetic polarity, and negative values indicate north magnetic polarity; therefore greater B values indicate a stronger south polarity field (or a weaker north polarity field, if present). 2The range of values specified for B RES is a maximum, derived from the cumulative programming bit errors. 3 A1184-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1184 Standard Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switch Characteristic Data ICC(H) versus Ambient Temperature at Various Levels of VCC (A1184) ICC(L) versus Ambient Temperature at Various Levels of VCC (A1184) 20 10 18 VCC (V) 6 3.5 12.0 24.0 4 ICC(H) (mA) ICC(L) (mA) 8 VCC (V) 16 3.5 12.0 24.0 14 12 2 0 10 -50 0 50 100 150 200 -50 0 Ambient Temperature, TA (°C) 150 200 Hysteresis versus Ambient Temperature at Various Levels of VCC (A1184) 30 700 600 25 400 300 200 100 0 VCC (V) BHYS (G) BOPinit Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 500 BOP (G) 100 Ambient Temperature, TA (°C) Average BOP Bits versus Ambient Temperature (A1184) -50 50 20 3.5 12.0 24.0 15 10 5 0 50 100 150 200 -50 0 50 100 150 200 Ambient Temperature, TA (°C) Ambient Temperature, TA (°C) Device Qualification Program Contact Allegro MicroSystems 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 4 A1184-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1184 Standard Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switch THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information Characteristic Symbol RθJA Package Thermal Resistance Test Conditions* Value Units Package LH, 1-layer PCB with copper limited to solder pads 228 ºC/W Package LH, 2-layer PCB with 0.463 in.2 of copper area each side connected by thermal vias 110 ºC/W Package UA, 1-layer PCB with copper limited to solder pads 165 ºC/W *Additional thermal information available on Allegro Web site. Maximum Allowable VCC (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 VCC(max) 2-layer PCB, Package LH (RθJA = 110 ºC/W) 1-layer PCB, Package UA (RθJA = 165 ºC/W) 1-layer PCB, Package LH (RθJA = 228 ºC/W) 20 40 60 80 100 VCC(min) 120 140 160 180 Temperature (ºC) 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 2l (R aye rP θJ C A = 11 B, P 0 º ac 1-la C/ ka W (R yer PC ) ge L θJA = B H 165 , Pac ºC/ kage W) UA 1-lay er P (R CB, θJA = 228 Packag ºC/W e LH ) 20 40 60 80 100 120 Temperature (°C) 140 160 180 5 A1184-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1184 Standard Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switch Functional Description Operation The output, ICC, of the A1184 device switches high 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 low. The differences between the magnetic operate and release point is called the hysteresis of the device, BHYS. This built-in hysteresis allows clean switching of the output even in the presence of external mechanical vibration and electrical noise. (See figure 1). I+ ICC Switch to Low Switch to High ICC(H) ICC(L) BRP B– BOP 0 B+ BHYS Figure 1. 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 A1184-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1184 Standard Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switch Chopper Stabilization Technique A limiting factor for switchpoint accuracy when using Hall effect technology is the small signal voltage developed across the Hall element. This voltage is proportionally small relative to the offset that can be produced at the output of the Hall sensor device. This makes it difficult to process the signal and maintain an accurate, reliable output over the specified temperature and voltage range. Chopper stabilization is a unique approach used to minimize Hall offset on the chip. The Allegro patented technique, dynamic quadrature offset cancellation, removes key sources of the output drift induced by temperature and package stress. This offset reduction technique is based on a signal modulation-demodulation process. The undesired offset signal is separated from the magnetically induced signal in the frequency domain through modulation. The subsequent demodulation acts as a modulation process for the offset causing the magnetically induced signal to recover its original spectrum at base band while the dc offset becomes a high frequency signal. Then, using a low-pass filter, the signal passes while the modulated dc offset is suppressed. 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 (400KHz). The sampling demodulation process produces higher accuracy and faster signal processing capability. Using this chopper stabilization approach, the chip is desensitized to the effects of temperature and stress. This technique produces devices that have an extremely stable quiescent Hall output voltage, is immune to thermal stress, and has precise recoverability after temperature cycling. This technique is made possible through the use of a BiCMOS process which allows the use of low-offset and low-noise amplifiers in combination with high-density logic integration and sample-and-hold circuits. The repeatability of switching with a magnetic field is slightly affected using a chopper technique. The Allegro high frequency chopping approach minimizes the affect of jitter and makes it imperceptible in most applications. Applications that may notice the degradation are those that require the precise sensing of alternating magnetic fields such as ring magnet speed sensing. For those applications, Allegro recommends the “low jitter” family of digital sensors. Regulator Hall Element Amp Sample and Hold Clock/Logic Low-Pass Filter Figure 2. Chopper stabilization circuit (dynamic quadrature offset cancellation) 7 A1184-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1184 Standard Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switch Application Information For additional general application information, visit the Allegro MicroSystems Web site at www. allegromicro.com. Typical Application Circuit The A118x 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 μF capacitor is typical. V+ VCC A118x Installation of CBYP must ensure that the traces that connect it to the A118x 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 A118x internal circuitry. As a result, the load ECU (electronic control unit) must have sufficient protection, other than CBYP, installed in parallel with the A118x. A series resistor on the supply side, RS (not shown), in combination with CBYP, creates a filter for EMI pulses. (Additional information on EMC is provided on the Allegro MicroSystems Web site.) When determining the minimum VCC requirement of the A118x 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 Ω. B GND CBYP 0.01 uF GND B A A Package UA Only B Maximum separation 5 mm RSENSE ECU Figure 3. Typical application circuit 8 A1184-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1184 Standard Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switch 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 (1) ΔT = PD × RθJA (2) TJ = TA + ΔT (3) Example: Reliability for VCC at TA = 150°C, package UA, using minimum-K PCB. Observe the worst-case ratings for the device, specifically: RθJA = 165°C/W, TJ(max) = 165°C, VCC(max) = 24 V, and ICC(max) = 17 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 ÷ 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 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 = 140 °C/W, then: PD = VCC × ICC = 12 V × 4 mA = 48 mW ΔT = PD × RθJA = 48 mW × 140 °C/W = 7°C TJ = TA + ΔT = 25°C + 7°C = 32°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. 9 A1184-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1184 Standard Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switch Programming Protocol V+ The operate switchpoint, BOP , can be field-programmed. To do so, a coded series of voltage pulses through the VCC pin is used to set bitfields in onboard registers. The effect on the device output can be monitored, and the registers can be cleared and set repeatedly until the required BOP is achieved. To make the setting permanent, bitfield-level solid state fuses are blown, and finally, a device-level fuse is blown, blocking any further coding. It is not necessary to program the release switchpoint, BRP , because the difference between BOP and BRP , referred to as the hysteresis, BHYS , is fixed. The range of values between BOP(min) and BOP(max) is scaled to 31 increments. The actual change in magnetic flux (G) represented by each increment is indicated by BRES (see the Operating Characteristics table; however, testing is the only method for verifying the resulting BOP). For programming, the 31 increments are individually identified using 5 data bits, which are physically represented by 5 bitfields in the onboard registers. By setting these bitfields, the corresponding calibration value is programmed into the device. Three voltage levels are used in programming the device: a low voltage, VPL , a minimum required to sustain register settings; a mid-level voltage, VPM , used to increment the address counter in the device; and a high voltage, VPH , used to separate sets of VPM pulses (when short in duration) and to blow fuses (when long in duration). A fourth voltage level, essentially 0 V, is used to clear the registers between pulse sequences. The pulse values are shown in the Programming Protocol Characteristics table and in figure 4. VPH VPM VPL Td(P) 0 Td(0) Td(1) t Figure 4. Pulse amplitudes and durations Additional information on device programming and programming products is available on www. allegromicro.com. Programming hardware is available for purchase, and programming software is available free of charge. Code Programming. Each bitfield must be individually set. To do so, a pulse sequence must be transmitted for each bitfield that is being set to 1. If more than one bitfield is being set to 1, all pulse sequences must be sent, one after the other, without allowing VCC to fall to zero (which clears the registers). The same pulse sequence is used to provisionally set bitfields as is used to permanently set bitfield-level fuses. The only difference is that when provisionally setting bitfields, no fuse-blowing pulse is sent at the end of the pulse sequence. PROGRAMMING PROTOCOL CHARACTERISTICS, over operating temperature range, unless otherwise noted Characteristic Symbol Min. Typ. Max. Units 4.5 5.0 5.5 V VPM 11.5 12.5 13.5 V VPH 25.0 26.0 27.0 V VPL Programming Voltage1 Programming Current2 Pulse Width Test Conditions Minimum voltage range during programming IPP tr = 11 μs; 5 V → 26 V; CBYP = 0.1 μF - 190 - mA td(0) OFF time between programming bits 20 - - μs td(1) Pulse duration for enable and addressing sequences 20 - - μs td(P) Pulse duration for fuse blowing 100 300 - μs Pulse Rise Time tr VPL to VPM; VPL to VPH 5 - 20 μs Pulse Fall Time tf VPM to VPL; VPH to VPL 5 - 100 μs 1Programming voltages are measured at the VCC pin. 2A bypass capacitor with a minimum capacitance of 0.1 provide the current necessary to blow the fuse. μF must be connected from VCC to the GND pin of the A118x device in order to 10 A1184-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1184 Standard Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switch The pulse sequences consist of the following groups of pulses: 1. An enable sequence. 2. A bitfield address sequence. 3. When permanently setting the bitfield, a long VPH fuse-blowing pulse. (Note: Blown bit fuses cannot be reset.) 4. When permanently setting the bitfield, the level of VCC must be allowed to drop to zero between each pulse sequence, in order to clear all registers. However, when provisionally setting bitfields, VCC must be maintained at VPL between pulse sequences, in order to maintain the prior bitfield settings while preparing to set additional bitfields. Bitfields that are not set are evaluated as zeros. The bitfield-level fuses for 0 value bitfields are never blown. This prevents inad- vertently setting the bitfield to 1. Instead, blowing the devicelevel fuse protects the 0 bitfields from being accidentally set in the future. When provisionally trying the calibration value, one pulse sequence is used, using decimal values. The sequence for setting the value 510 is shown in figure 5. When permanently setting values, the bitfields must be set individually, and 510 must be programmed as binary 101. Bit 3 is set to 1 (0001002, which is 410), then bit 1 is set to 1 (0000012, which is 110). Bit 2 is ignored, and so remains 0.Two pulse sequences for permanently setting the calibration value 5 are shown in figure 6. The final VPH pulse is maintained for a longer period, enough to blow the corresponding bitfield-level fuse. V+ VPH VPM VPL 0 Enable Address Try 510 Optional Monitoring Clear t Figure 5. Pulse sequence to provisionally try calibration value 5. V+ VPH VPM VPL Address 0 Enable Address Encode 001002 (410) Blow Enable Blow Encode 000012 (110) Figure 6. Pulse sequence to permanently encode calibration value 5 (101 binary, or bitfield address 3 and bitfield address 1). t 11 A1184-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1184 Standard Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switch V+ Enabling Addressing Mode. The first segment of code is a keying sequence used to enable the bitfield addressing mode. As shown in figure 7, this segment consists of one short VPH pulse, one VPM pulse, and one short VPH pulse, with no supply interruptions. This sequence is designed to prevent the device from being programmed accidentally, such as by noise on the supply line. VPH VPM VPL 0 t Figure 7. Addressing mode enable pulse sequence V+ VPH Address 1 Address 2 Address n ( ≤ 31) Address Selection. After addressing mode is enabled, the VPM target bitfield address, is indicated by a series of VPM pulses, as shown in figure 8. VPL 0 t Figure 8. Pulse sequence to select addresses V+ Falling edge of final BOP address digit VPH Lock Bit Programming. After the desired BOP calibration value is programmed, and all of the corresponding bitfield-level fuses are blown, the device-level fuse should be blown. To do so, the lock bit (bitfield address 32) should be encoded as 1 and have its fuse blown. This is done in the same manner as permanently setting the other bitfields, as shown in figure 9. VPM VPL 32 pulses 0 Enable Address Blow Encode Lock Bit Figure 9. Pulse sequence to encode lock bit t 12 A1184-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1184 Standard Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switch Package LH, 3-Pin (SOT-23W) 3.10 .122 2.90 .114 1.49 .059 NOM 3 8º 0º 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 .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 A1184-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com A1184 Standard Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switch 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 © 2004, 2005 Allegro MicroSystems, Inc. 14 A1184-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com