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| A1180/81/82/83 Sensitive Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall-Effect Switches The A1180, A1181, A1182, and A1183 devices are sensitive, 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 A1180-83 family of devices are 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 A1180-83 family of devices also features on-chip transient protection, and a Zener clamp to protect against overvoltage conditions on the supply line. The output currents of the A1181 and A1183 switch HIGH in the presence of a south polarity magnetic field of sufficient strength; and switch LOW otherwise, including when there is no significant magnetic field present. The A1180 and A1182 have inverted output current levels: switching LOW in the presence of a south polarity magnetic field of sufficient strength, and HIGH otherwise. The devices also differ in their specified LOW current supply levels. 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. 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 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.................. -40C to 85C Ambient, TA, Range L................ -40C to 150C Maximum Junction, TJ(max)........................165C Storage Temperature, TS .................. -65C to 170C Features and Benefits Chopper stabilization Low switchpoint drift over operating temperature range Low stress sensitivity Field-programmable for optimized switchpoints 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 A1180-DS, Rev. 2 A1180/81/82/83 Sensitive Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switches Product Selection Guide Part Number A1180ELHLT A1180ELHLT-T A1180EUA A1180EUA-T A1180LLHLT A1180LLHLT-T A1180LUA A1180LUA-T A1181ELHLT A1181ELHLT-T A1181EUA A1181EUA-T A1181LLHLT A1181LLHLT-T A1181LUA A1181LUA-T A1182ELHLT3 A1182ELHLT-T A1182EUA A1182EUA-T A1182LLHLT A1182LLHLT-T A1182LUA A1182LUA-T A1183ELHLT3 A1183ELHLT-T A1183EUA A1183EUA-T A1183LLHLT A1183LLHLT-T A1183LUA A1183LUA-T 1Contact Pbfree - Yes - Yes - Yes - Yes - Yes - Yes - Yes - Yes - Yes - Yes - Yes - Yes - Yes - Yes - Yes - Yes Packing1 Mounting Ambient, TA (C) Output South (+) Field2 Supply Current at Low Output, ICC(L) (mA) 7-in. reel, 3000 pieces/reel Bulk, 500 pieces/bag 7-in. reel, 3000 pieces/reel Bulk, 500 pieces/bag 7-in. reel, 3000 pieces/reel Bulk, 500 pieces/bag 7-in. reel, 3000 pieces/reel Bulk, 500 pieces/bag 7-in. reel, 3000 pieces/reel Bulk, 500 pieces/bag 7-in. reel, 3000 pieces/reel Bulk, 500 pieces/bag 7-in. reel, 3000 pieces/reel Bulk, 500 pieces/bag 7-in. reel, 3000 pieces/reel Bulk, 500 pieces/bag Surface mount -40 to 85 4-pin SIP through hole Low Surface mount -40 to 150 4-pin SIP through hole 2 to 5 Surface mount -40 to 85 4-pin SIP through hole High Surface mount -40 to 150 4-pin SIP through hole Surface mount -40 to 85 4-pin SIP through hole Low Surface mount -40 to 150 4-pin SIP through hole 5 to 6.9 Surface mount -40 to 85 4-pin SIP through hole High Surface mount -40 to 150 4-pin SIP through hole 2South Allegro for additional packing options. (+) magnetic fields must be of sufficient strength. 3These 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. A1180-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 2 A1180/81/82/83 Sensitive Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switches Functional Block Diagram V+ VCC Program/Lock Programming Logic Offset Regulator Clock/Logic 0.01 uF Sample and Hold Dynamic Offset Cancellation Low-Pass Filter Amp GND Package UA Only GND A1180-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 3 A1180/81/82/83 Sensitive Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switches ELECTRICAL CHARACTERISTICS over the operating voltage and temperature range, unless otherwise specified Characteristic Supply Voltage1 Symbol VCC ICC(L) ICC(H) Supply Zener Clamp Voltage Supply Zener Clamp Current Reverse Supply Current Output Slew Rate3 Chopping Frequency Power-On Time4 Power-On State5,6 1V Test Conditions Device powered on B >BOP for A1180; B Typ. - - - - - - - 36 200 - HIGH Max. 24 5 6.9 17 40 ICC(L)(max) + 3 mA -1.6 - - 25 - Units V mA mA mA V mA mA mA/s kHz s - Supply Current2 VZ(supply) IZ(supply) IRCC di/dt fC ton POS CC represents the generated voltage between the VCC pin and the GND pin. 2Relative 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). 3Measured without bypass capacitor between VCC and GND. Use of a bypass capacitor results in slower current change. 4Measured with and without bypass capacitor of 0.01 F. Adding a larger bypass capacitor causes longer Power-On Time. 5POS is defined as true only with a V CC slew rate of 25 mV / s or greater. Operation with a VCC slew rate less than 25 mV / s can permanently harm device performance. 6POS is undefined for t > t or B on RP < B < BOP . MAGNETIC CHARACTERISTICS1 over the operating voltage and temperature range, unless otherwise specified Characteristic Programmable Operate Point Range Initial Operate Point Range Switchpoint Step Size2 Number of Programming Bits Temperature Drift of BOP Hysteresis 1Relative Symbol BOPrange BOPinit BRES - Test Conditions ICC = ICC(H) for A1180 and A1182 ICC = ICC(L) for A1181 and A1183 VCC = 12 V VCC = 5 V, TA = 25C Switchpoint setting Programming locking Min. 60 - 4 - - - Typ. - 33 8 5 1 - 15 Max. 200 60 12 - - 20 30 Units G G G Bit Bit G G BOP BHYS BHYS = BOP - BRP 5 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. A1180-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 4 A1180/81/82/83 Sensitive Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switches Characteristic Data ICC(L) versus Ambient Temperature at Various Levels of VCC (A1180, A1181) 10 8 ICC(L) (mA) 6 4 2 0 -50 0 50 100 150 200 ICC(L) (mA) VCC (V) 3.5 12 24 ICC(L) versus Ambient Temperature at Various Levels of VCC (A1182, A1183) 10 8 VCC (V) 6 4 2 0 -50 0 50 100 150 200 3.5 12 24 Ambient Temperature, TA (C) Ambient Temperature, TA (C) ICC(H) versus Ambient Temperature at Various Levels of VCC (A1180, A1181, A1182, A1183) 20 18 ICC(H) (mA) VCC (V) 16 14 12 10 -50 3.5 12 24 0 50 100 150 200 Ambient Temperature, TA (C) Average BOP Bits versus Ambient Temperature (A1180, A1181, A1182, A1183) Hysteresis versus Ambient Temperature at Various Levels of VCC (A1180, A1181, A1182, A1183) 30 BOPinit Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 25 BHYS (G) 20 15 10 5 VCC (V) 3.5 12 24 200 Average BOP (G) 175 150 125 100 75 50 25 0 -50 0 50 100 150 200 -50 0 50 100 150 200 Ambient Temperature, TA (C) Ambient Temperature, TA (C) A1180-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 5 A1180/81/82/83 Sensitive Two-Wire Field-Programmable 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 ESD - Human Body Model ESD - Machine Model Conducted Transients Direct RF Injection Bulk Current Injection TEM Cell Reference Specification AEC-Q100-002 AEC-Q100-003 ISO 7637-1 ISO 11452-7 ISO 11452-4 ISO 11452-3 A1180-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 6 A1180/81/82/83 Sensitive Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switches THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information Characteristic Symbol Test Conditions* Package LH, 1-layer PCB with copper limited to solder pads Package Thermal Resistance RJA Package LH, 2-layer PCB with 0.463 in.2 of copper area each side connected by thermal vias Package UA, 1-layer PCB with copper limited to solder pads *Additional thermal information available on Allegro Web site. Value Units 228 110 165 C/W C/W C/W 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 VCC(max) Maximum Allowable VCC (V) 2-layer PCB, Package LH (RJA = 110 C/W) 1-layer PCB, Package UA (RJA = 165 C/W) 1-layer PCB, Package LH (RJA = 228 C/W) VCC(min) 120 140 160 180 40 60 80 100 Temperature (C) 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 20 Power Dissipation, PD (m W) 2l (R aye rP J C A= 11 B, P 0 ac 1-la C/ ka W (R yer PC ) ge L JA = B H 165 , Pac C/ kage W) UA 1-lay er P (R CB, JA = 228 Packag C/W e LH ) 40 60 80 100 120 Temperature (C) 140 160 180 A1180-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 7 A1180/81/82/83 Sensitive Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switches Functional Description Operation The output, ICC, of the A1180 and A1182 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 builtin hysteresis allows clean switching of the output even in the presence of external mechanical vibration and electrical noise. The A1181 and A1183 devices switch with opposite polarity for similar BOP and BRP values, in comparison to the A1180 and A1183 (see figure 1). I+ ICC(H) I+ ICC(H) Switch to High ICC(L) 0 Switch to High Switch to Low Switch to Low ICC ICC ICC(L) 0 BRP BHYS BHYS (A) A1180 and A1182 (B) A1181 and A1183 Figure 1. Alternative switching behaviors are available in the A118x 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). BOP B- B+ B- B+ BRP BOP A1180-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 8 A1180/81/82/83 Sensitive Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switches 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 Clock/Logic Hall Element Amp Low-Pass Filter Figure 2. Chopper stabilization circuit (dynamic quadrature offset cancellation) Sample and Hold A1180-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 9 A1180/81/82/83 Sensitive Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switches 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 F capacitor is typical. 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 . GND A A B Package UA Only Maximum separation 5 mm V+ VCC B A118x CBYP 0.01 uF GND B RSENSE ECU Figure 3. Typical application circuit A1180-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 10 A1180/81/82/83 Sensitive Two-Wire Field-Programmable 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 T = PD x RJA TJ = TA + T (1) (2) (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. A1180-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 11 A1180/81/82/83 Sensitive Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switches Programming Protocol 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 V+ 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 VPL Programming Voltage1 VPM VPH Programming Current2 IPP td(0) Pulse Width td(1) td(P) Pulse Rise Time Pulse Fall Time tr tf tr = 11 s; 5 V 26 V; CBYP = 0.1 F OFF time between programming bits Pulse duration for enable and addressing sequences Pulse duration for fuse blowing VPL to VPM; VPL to VPH VPM to VPL; VPH to VPL Test Conditions Minimum voltage range during programming Min. 4.5 11.5 25.0 20 20 100 5 5 Typ. 5.0 12.5 26.0 190 300 Max. 5.5 13.5 27.0 20 100 Units V V V mA s s s s s 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. F must be connected from VCC to the GND pin of the A118x device in order to A1180-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 12 A1180/81/82/83 Sensitive Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switches 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 Try 510 Address 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) t Figure 6. Pulse sequence to permanently encode calibration value 5 (101 binary, or bitfield address 3 and bitfield address 1). A1180-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 13 A1180/81/82/83 Sensitive Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switches V+ VPH 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. 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 Encode Lock Bit Blow Figure 9. Pulse sequence to encode lock bit t A1180-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 14 A1180/81/82/83 Sensitive Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switches Package LH, 3-Pin (SOT-23W) 3.10 .122 2.90 .114 1.49 .059 NOM 3 0.28 .011 NOM 8 0 0.20 .008 0.13 .005 0.70 .028 BSC C 0.96 .038 NOM 2.10 .083 1.85 .073 3.00 .118 2.70 .106 2.40 .094 BSC 0.25 .010 MIN 1.00 .039 BSC 1 2 0.25 .010 BSC Seating Plane Gauge Plane A A 0.95 .037 BSC Dimensions in millimeters U.S. Customary dimensions (in.) in brackets, for reference only Hall element Active Area Depth 0.28 [.011] Fits SC-59A Solder Pad Layout 0.50 .020 0.30 .012 0.55 .022 REF 1.13 .045 0.87 .034 0.95 .037 BSC 0.15 .006 0.00 .000 B C Package UA, 3-Pin .164 4.17 .159 4.04 45 BSC .0195 0.50 NOM .0805 2.04 NOM .0565 1.44 NOM B .062 1.57 .058 1.47 .122 3.10 .117 2.97 45 BSC .085 2.16 MAX .031 0.79 REF A .640 16.26 .600 15.24 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 A1180-DS, Rev. 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 15 A1180/81/82/83 Sensitive Two-Wire Field-Programmable 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. Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 16 A1180-DS, Rev. 2 |
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