Chopper-Stabilized Omnipolar Hall-Effect Switches

A3245 Chopper-Stabilized Omnipolar Hall-Effect Switches Features and Benefits ▪ Omnipolar operation ▪ Chopper stabilization ▫ Superior temperature stability ▫ Extremely low switchpoint drift ▫ Insensitive to physical stress ▪ Reverse battery protection ▪ Output short circuit protection ▪ Solid state reliability ▪ Small size ▪ Robust EMC capability ▪ High ESD ratings (HBM) Description The A3245 integrated circuit is an omnipolar, ultrasensitive Hall-effect switch with a digital output. This sensor has an integrated regulator permitting operation to 24 V, making it the first omnipolar switch available for operation to 24 V. This device is especially suited for operation over extended temperature ranges, up to +150°C. Superior high-temperature performance is made possible through an Allegro® patented dynamic offset cancellation, which reduces the residual offset voltage normally caused by device overmolding, temperature excursions, and thermal stress. The A3245 Hall-effect switch includes the following on a single silicon chip: voltage regulator, Hall-voltage generator, smallsignal amplifier, chopper stabilization, Schmitt trigger, and a short circuit protected open-drain output. Advanced BiCMOS wafer fabrication processing is used to take advantage of lowvoltage requirements, component matching, very low inputoffset errors, and small component geometries. Packages: 3 pin SOT23W (suffix LH), and 3 pin SIP (suffix UA) The omnipolar operation of the A3245 allows activation with either a north or a south polarity field of sufficient strength. In the absence of a magnetic field, the output is off. This patented www.DataSheet4U.com Continued on the next page… Not to scale Functional Block Diagram VCC Regulator To All Subcircuits Sample and Hold Dynamic Offset Cancellation Low-Pass Filter VOUT Amp Amp Control Current Limit <1Ω GND A3245-DS, Rev. 2 A3245 Chopper-Stabilized Omnipolar Hall Effect Switches process allow these devices to be provided in ultrasmall packages. The package styles available provide magnetically optimized solutions for most applications. Package LH is an SOT23W, a miniature low-profile surface-mount package, while package UA is a three-lead ultramini SIP for through-hole mounting. Each package is available in a lead (Pb) free version, with 100% matte tin plated leadframes. Description (continued) magnetic-polarity-independence feature makes this device an excellent replacement for reed switches, with improved ease of manufacturing, because the A3245 does not require manufacturers to orient their magnets. These devices allow simple on/off switching in industrial, consumer, and automotive applications. The A3245 is rated for operation between the ambient temperatures –40°C and 85°C for the E temperature range, and –40°C to 150°C for the L temperature range. The small geometries of the BiCMOS Selection Guide Part Number A3245ELHLT-T A3245EUA-T A3245LLHLT-T A3245LUA-T 1Pb-based Pb-Free1 Yes Yes Yes Yes Packing2 7-in. reel, 3000 pieces/reel Bulk, 500 pieces/bag 7-in. reel, 3000 pieces/reel Bulk, 500 pieces/bag Mounting 3-pin SOT23W surface mount 3-pin SIP through hole 3-pin SOT23W surface mount 3-pin SIP through hole Ambient, TA (°C) –40 to 85 –40 to 150 variants are being phased out of the product line. Certain variants cited in this footnote 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 change: May 1, 2006. These variants include: A3245ELHLT, A3245EUA, A3245LLHT, and A3245LUA. for additional packing options. 2Contact Allegro Absolute Maximum Ratings Characteristic Supply Voltage Reverse-Supply Voltage Reverse-Supply Current Output Off Voltage Output Current Magnetic Flux Density Operating Ambient Temperature Maximum Junction Temperature Storage Temperature Symbol VCC VRCC IRCC VOUT IOUTSINK B TA TJ(max) Tstg Range E Range L Notes Rating 28 –18 –2 28 Internally Limited Unlimited –40 to 85 –40 to 150 165 –65 to 170 Units V V mA V – G ºC ºC ºC ºC Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 2 A3245 Chopper-Stabilized Omnipolar Hall Effect Switches OPERATING CHARACTERISTICS valid over full operating voltage and ambient temperature ranges, unless otherwise noted Characteristic Electrical Characteristics Supply Voltage1 Output Leakage Current Output On Voltage Output Current Limit Power-On Time Chopping Frequency Output Rise Time2 Output Fall Time2 Supply Current Reverse Battery Current Supply Zener Clamp Voltage Supply Zener Current3 Magnetic Characteristics4 Operate Point Release Point Hysteresis 1 2 Symbol VCC IOUTOFF VOUT(SAT) IOM tPO fc tr tf ICCON ICCOFF IRCC VZSupply IZSupply BOPS BOPN BRPS BRPN BHYS Test Conditions Operating, TJ < 165°C VOUT = 24 V, B < BRP IOUT = 20 mA, B > BOP B > BOP VCC > VCC(MIN) RLOAD = 820 Ω, CS = 20 pF RLOAD = 820 Ω, CS = 20 pF B > BOP B < BRP VRCC = –18 V ICC = 6.5 mA; TA = 25°C VS = 28 V South pole adjacent to branded face of device North pole adjacent to branded face of device South pole adjacent to branded face of device North pole adjacent to branded face of device |BOPX – BRPX| Min. 3.6 – – 30 – – – – – – – 28 – 15 –55 5 –50 5 Typ. – – – – – 200 – – 1.5 1.5 – – – 38 –38 20 –20 18 Max. 24 10 500 60 50 – 1 1 3.5 3.5 –2 – 6.5 55 –15 50 –5 30 Units V μA mV mA μs kHz μs μs mA mA mA V mA G G G G G Maximum voltage must be adjusted for power dissipation and junction temperature, see Power Derating section. CS = oscilloscope probe capacitance. 3 Maximum current limit is equal to the maximum I CC(MAX) + 3 mA. 4 Magnetic flux density, B, is indicated as a negative value for north-polarity magnetic fields, and as a positive value for south-polarity magnetic fields. This so-called algebraic convention supports arithmetic comparison of north and south polarity values, where the relative strength of the field is indicated by the absolute value of B, and the sign indicates the polarity of the field (for example, a –100 G field and a 100 G field have equivalent strength, but opposite polarity). DEVICE QUALIFICATION PROGRAM Contact Allegro for information. EMC (Electromagnetic Compatibility) REQUIREMENTS Contact Allegro for information. Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 3 A3245 Chopper-Stabilized Omnipolar Hall Effect Switches Electrical Characteristic Data Supply Current (On) versus Ambient Temperature 5.0 4.0 5.0 4.0 Supply Current (On) versus Supply Voltage ICCON (mA) 3.0 2.0 1.0 0 –50 0 50 TA (°C) 100 150 ICCON (mA) VCC (V) 24 3.6 TA (°C) –40 25 150 3.0 2.0 1.0 0 0 5 10 VCC (V) 15 20 25 Supply Current (Off) versus Ambient Temperature Supply Current (Off) versus Supply Voltage 5.0 4.0 5.0 4.0 ICCOFF (mA) ICCOFF (mA) VCC (V) 3.0 2.0 1.0 0 –50 0 50 TA (°C) 100 150 24 3.6 TA (°C) –40 25 150 3.0 2.0 1.0 0 0 5 10 VCC (V) 15 20 25 Output Voltage (On) versus Ambient Temperature 500 450 400 350 500 450 400 350 Output Voltage (On) versus Supply Voltage VOUT(SAT) (mV) VOUT(SAT) (mV) 300 250 200 150 100 50 0 –50 0 50 TA (°C) 100 150 VCC (V) 24 3.6 300 250 200 150 100 50 0 0 5 10 VCC (V) 15 20 25 TA (°C) –40 25 150 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 4 A3245 Chopper-Stabilized Omnipolar Hall Effect Switches Magnetic Characteristic Data Operate Point (South) versus Ambient Temperature 55 50 45 40 BOPS (G) VCC (V) 24 3.6 Operate Point (North) versus Ambient Temperature -15 -20 -25 -30 BOPN (G) VCC (V) 24 3.6 35 30 25 20 15 –50 0 50 TA (°C) 100 150 -35 -40 -45 -50 -55 –50 0 50 TA (°C) 100 150 Release Point (South) versus Ambient Temperature 50 45 40 35 24 3.6 VCC (V) Release Point (North) versus Ambient Temperature -5 -10 -15 -20 BRPN (G) VCC (V) 24 3.6 BRPS (G) 30 25 20 15 10 5 –50 0 50 TA (°C) 100 150 -25 -30 -35 -40 -45 -50 –50 0 50 TA (°C) 100 150 Hysteresis versus Ambient Temperature 30 25 20 15 10 5 –50 0 50 TA (°C) 100 150 VCC (V) 24 3.6 Continued on the next page... Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com BHYS (G) 5 A3245 Chopper-Stabilized Omnipolar Hall Effect Switches Magnetic Characteristic Data (Continued) Operate Point (South) versus Supply Voltage 55 50 45 40 BOPS (G) TA (°C) Operate Point (North) versus Supply Voltage -15 -20 -25 -30 BOPN (G) TA (°C) –40 25 150 35 30 25 20 15 0 5 10 VCC (V) 15 20 25 –40 25 150 -35 -40 -45 -50 -55 0 5 10 VCC (V) 15 20 25 Release Point (South) versus Supply Voltage 50 45 40 35 BRPS (G) TA (°C) Release Point (North) versus Supply Voltage -5 -10 -15 -20 BRPN (G) TA (°C) –40 25 150 30 25 20 15 10 5 0 5 10 VCC (V) 15 20 25 –40 25 150 -25 -30 -35 -40 -45 -50 0 5 10 VCC (V) 15 20 25 Hysteresis versus Supply Voltage 30 25 20 15 10 5 0 5 10 VCC (V) 15 20 25 TA (°C) –40 25 150 BHYS (G) Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 6 A3245 Chopper-Stabilized Omnipolar Hall Effect Switches THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information Characteristic Symbol Test Conditions Package LH-3, 1-layer PCB with copper limited to solder pads Package LH-3, 2-layer PCB with 0.926 in2 on each side, connected by thermal vias Package UA, 1-layer PCB with copper limited to solder pads Value 110 228 165 Units ºC/