Chopper-Stabilized Hall-Effect Bipolar Switch Package 3-pin Surfa

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Chopper-Stabilized Hall-Effect Bipolar Switch Package 3-pin Surfa

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A3230
Chopper-Stabilized Hall-Effect Bipolar Switch
Package 3-pin Surface Mount
A3230 Hall-effect sensor temperature stable, stress-resistant bipolar switch. This sensor most sensitive Hall-effect device Allegro® bipolar switch family intended ring-magnet sensing. Superior high-temperature performance made possible through Allegro patented dynamic offset cancellation that utilizes chopper-stabilization. This method reduces offset voltage normally caused device overmolding, temperature dependencies, thermal stress. A3230 includes following single silicon chip: voltage regulator, Hall-voltage generator, small-signal amplifier, chopper stabilization, Schmitt trigger, short circuit protected open-drain output. Advanced BiCMOS wafer fabrication processing takes advantage low-voltage requirements, component matching, very input-offset errors, small component geometries. A3230 Hall-effect bipolar switch turns south polarity magnetic field sufficient strength switches north polarity magnetic field sufficient strength. Because output state defined magnetic field diminished removed, ensure that device switches, Allegro recommends using magnets both polarities sufficient strength application. A3230 rated operation between ambient temperatures -40°C 85°C temperature range, -40°C 150°C temperature range. A3230 package styles provide magnetically optimized solutions
Package 3-pin
VOUT
VOUT
most applications. Package SOT23W, miniature low-profile surface-mount package, while package three-lead ultramini through-hole mounting. Each package available lead (Pb) free version, with 100% matte plated leadframes.
Features Benefits
Chopper stabilization Superior temperature stability Extremely switchpoint drift Insensitive physical stress Reverse battery protection Output short circuit protection Solid state reliability Small size Robust capability High ratings (HBM)
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, Reverse-Supply Voltage, VRCC Output Voltage, VOUT 26.5 Output Current, IOUTSINK Internally Limited Reverse-Output Current, IROUT .-10 Magnetic Flux Density, .Unlimited Operating Temperature Ambient, Range Ambient, Range Maximum Junction, TJ(MAX) Storage Temperature,
A3230-DS
Allegro MicroSystems, Inc. Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
A3230
Chopper-Stabilized Hall Effect Bipolar Switch
Product Selection Guide
Part Number Pbfree Packing* Mounting 3-pin SOT23W surface mount 3-pin through hole 3-pin SOT23W surface mount 3-pin through hole Ambient, (°C) BRP(MIN) BOP(MAX)
A3230ELHLT 7-in. reel, 3000 pieces/reel A3230ELHLT-T A3230EUA Bulk, pieces/bag A3230EUA-T A3230LLHLT 7-in. reel, 3000 pieces/reel A3230LLHLT-T A3230LUA Bulk, pieces/bag A3230LUA-T *Contact Allegro additional packing options.
Functional Block Diagram
Regulator
Subcircuits Sample Hold Dynamic Offset Cancellation Low-Pass Filter
VOUT
Control
Current Limit
Terminal List
Name VOUT Description Connects power supply chip Output from circuit Ground Number Package Package
A3230-DS
Allegro MicroSystems, Inc. Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
A3230
Chopper-Stabilized Hall Effect Bipolar Switch
OPERATING CHARACTERISTICS valid over full operating voltage ambient temperature ranges, unless otherwise noted Characteristic Electrical Characteristics Supply Voltage1 Output Leakage Current Output 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
Symbol IOUTOFF VOUT(SAT) ICCON ICCOFF IRCC BHYS
Test Conditions Operating, 165°C VOUT IOUT RLOAD RLOAD VRCC 25°C South pole adjacent branded face device North pole adjacent branded face device
Min.
Typ. -7.5
Max.
Units
Maximum voltage must adjusted power dissipation junction temperature, Power Derating section. oscilloscope probe capacitance. Maximum current limit equal maximum CC(MAX) Magnetic flux density, indicated negative value north-polarity magnetic fields, positive value south-polarity magnetic fields. This so-called algebraic convention supports arithmetic comparison north south polarity values, where relative strength field indicated absolute value sign indicates polarity field (for example, -100 field field have equivalent strength, opposite polarity).
DEVICE QUALIFICATION PROGRAM Contact Allegro information. (Electromagnetic Compatibility) REQUIREMENTS Contact Allegro information.
A3230-DS
Allegro MicroSystems, Inc. Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
A3230
Chopper-Stabilized Hall Effect Bipolar Switch
Electrical Characteristic Data
Supply Current (On) versus Ambient Temperature
Supply Current (On) versus Supply Voltage
ICCON (mA)
(°C)
ICCON (mA)
(°C)
Supply Current (Off) versus Ambient Temperature
Supply Current (Off) versus Supply Voltage
ICCOFF (mA)
ICCOFF (mA)
(°C)
(°C)
Output Voltage (On) versus Ambient Temperature
Output Voltage (On) versus Supply Voltage
VOUT(SAT) (mV)
VOUT(SAT) (mV)
(°C)
(°C)
A3230-DS
Allegro MicroSystems, Inc. Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
A3230
Chopper-Stabilized Hall Effect Bipolar Switch
Magnetic Characteristic Data
Operate Point versus Ambient Temperature
Operate Point versus Supply Voltage
(°C)
(°C)
Release Point versus Ambient Temperature
Release Point versus Supply Voltage
(°C)
(°C)
Hysteresis versus Ambient Temperature
Hysteresis versus Supply Voltage
BHYS
BHYS
(°C)
(°C)
A3230-DS
Allegro MicroSystems, Inc. Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
A3230
Chopper-Stabilized Hall Effect Bipolar Switch
THERMAL CHARACTERISTICS require derating maximum conditions, application information
Characteristic Symbol Test Conditions Package minimum-K (single-sided with copper limited solder pads) Package low-K (double-sided with 0.926 copper area) Package minimum-K (single-sided with copper limited solder pads) Value Units
Package Thermal Resistance
Power Derating Curve TJ(max) 165°C; ICC(max)
CC(max)
Maximum Allowable
Low-K PCB, Package °C/W) Minimum-K PCB, Package °C/W) Minimum-K PCB, Package °C/W) CC(min)
Temperature (°C)
Power Dissipation versus Ambient Temperature
1900 1800 1700 1600 1500 1400 1300 1200 1100 1000
Power Dissipation, (mW)
Low-K PCB, Package °C/W) Min-K PCB, Package °C/W)
Min-K PCB, Package °C/W)
Temperature (°C)
Allegro MicroSystems, Inc. Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
A3230-DS
A3230
Chopper-Stabilized Hall Effect Bipolar Switch
Functional Description
Operation output these devices switches (turns when magnetic field perpendicular Hall sensor exceeds operate point threshold, BOP. After turn-on, output voltage VOUT(SAT). output transistor capable sinking current short circuit current limit, IOM, which minimum When magnetic field reduced below release point, BRP, device output goes high (turns off). difference magnetic operate release points hysteresis, BHYS, device. This built-in hysteresis allows clean switching output even presence external mechanical vibration electrical noise. There three switching modes bipolar devices, referred latch, unipolar switch, negative switch. Mode determined switchpoint characteristics individual device. Note that, shown figure these switchpoints either north south polarity ranges. values magnetic parameters A3230 specified Magnetic Characteristics table, page Bipolar devices typically behave latches (although these devices guaranteed so). this mode, magnetic fields opposite polarity equivalent strengths needed switch output. When magnetic fields removed device remains same state until magnetic field opposite polarity sufficient strength causes switch. hysteresis latch mode behavior shown panel figure contrast latching, when device exhibits unipolar switching, only responds south magnetic field. field must sufficient strength, device operate. When field reduced beyond level, device switches back high state, shown panel figure Devices
CBYP
RLOAD Sensor Output
A3230
VOUT
Switch High Switch High Switch Switch
Switch High
Switch
VOUT
VOUT
VOUT(SAT) BOP(MAX)
VOUT(SAT) BRP(MIN)
VOUT
VOUT(SAT)
BHYS
BHYS
BHYS
Figure Bipolar Device Output Switching Modes. These behaviors exhibited when using circuit such that shown panel Panel displays hysteresis when device exhibits latch mode (note that BHYS band incorporates panel shows unipolar switch behavior (the BHYS band more positive than panel shows negative switch behavior (the BHYS band more negative than Bipolar devices, such A3230, operate three modes.
A3230-DS
Allegro MicroSystems, Inc. Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
A3230
Chopper-Stabilized Hall Effect Bipolar Switch
exhibiting negative switch behavior operate similar opposite manner. north polarity field sufficient strength, (more north than BRP) required operation, although result that VOUT switches high, shown panel When field reduced beyond level, device switches back state. A3230 designed attain small hysteresis, thereby provide more sensitive switching. Although this means that true latching behavior cannot guaranteed cases, proper switching ensured both south north magnetic fields, ring magnet. Bipolar devices adopt indeterminate output state when powered-on absence magnetic field field that lies within hysteresis band device. correct state attained after first excursion beyond BRP. more information Bipolar switches, refer Application Note 27705, Understanding Bipolar Hall Effect Sensors.
Applications strongly recommended that external bypass capacitor connected close proximity Hall sensor) between supply ground device reduce both external noise noise generated chopper stabilization technique. shown Panel figure 0.1µF capacitor typical. Extensive applications information magnets Hall-effect sensors available Hall-Effect Applications Guide, AN27701, Hall-Effect Devices: Gluing, Potting, Encapsulating, Lead Welding Lead Forming, AN27703.1 Soldering Methods Allegro's Products ThroughHole, AN26009 provided Allegro Electronic Data Book, AMS-702 Allegro site: www.allegromicro.com
A3230-DS
Allegro MicroSystems, Inc. Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
A3230
Chopper-Stabilized Hall Effect Bipolar Switch
Chopper Stabilization Technique When using Hall-effect technology, limiting factor switchpoint accuracy small signal voltage developed across Hall element. This voltage disproportionally small relative offset that produced output Hall sensor. This makes difficult process signal while maintaining accurate, reliable output over specified operating temperature voltage ranges. Chopper stabilization unique approach used minimize Hall offset chip. patented Allegro technique, namely Dynamic Quadrature Offset Cancellation, removes sources output drift induced thermal mechanical stresses. This offset reduction technique based signal modulationdemodulation process. undesired offset signal separated from magnetic-field-induced signal frequency domain, through modulation. subsequent demodulation acts modulation process offset, causing magnetic-fieldinduced signal recover original spectrum baseband, while offset becomes high-frequency signal. magnetic-field-induced signal then pass through low-pass filter, while modulated offset suppressed. This configuration illustrated figure
chopper stabilization technique uses high-frequency clock. demodulation process, sample hold technique used, where sampling performed twice chopper frequency (400 kHz). This high-frequency operation allows greater sampling rate, which results higher accuracy faster signal-processing capability. This approach desensitizes chip effects thermal mechanical stresses, produces devices that have extremely stable quiescent Hall output voltages precise recoverability after temperature cycling. This technique made possible through BiCMOS process, which allows low-offset, low-noise amplifiers combination with high-density logic integration sample-and-hold circuits. repeatability magnetic-field-induced switching affected slightly chopper technique. However, Allegro highfrequency chopping approach minimizes affect jitter makes imperceptible most applications. Applications that more likely sensitive such degradation those requiring precise sensing alternating magnetic fields; example, speed sensing ring-magnet targets. such applications, Allegro recommends digital sensor families with lower sensitivity jitter. more information those devices, contact your Allegro sales representative.
Regulator
Clock/Logic Hall Element
Sample Hold
Figure Chopper Stabilization Circuit (Dynamic Quadrature Offset Cancellation)
Low-Pass Filter
A3230-DS
Allegro MicroSystems, Inc. Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
A3230
Chopper-Stabilized Hall Effect Bipolar Switch
Power Derating device must operated below maximum junction temperature device, TJ(max). Under certain combinations peak conditions, reliable operation require derating supplied power improving heat dissipation properties application. This section presents procedure correlating factors affecting operating (Thermal data also available Allegro MicroSystems site.) Package Thermal Resistance, RJA, figure merit summarizing ability application device dissipate heat from junction (die), through paths ambient air. primary component Effective Thermal Conductivity, printed circuit board, including adjacent devices traces. Radiation from through device case, RJC, relatively small component RJA. Ambient temperature, motion significant external factors, damped overmolding. effect varying power levels (Power Dissipation, PD), estimated. following formulas represent fundamental relationships used estimate
Example: Reliability 150°C, package using low-K PCB. Observe worst-case ratings device, specifically: °C/W, TJ(max) 165°C, VCC(max) ICC(max) Calculate maximum allowable power level, PD(max). First, invert equation Tmax TJ(max) This provides allowable increase resulting from internal power dissipation. Then, invert equation PD(max) Tmax 15°C °C/W Finally, invert equation with respect voltage: VCC(est) PD(max) ICC(max) result indicates that, application device dissipate adequate amounts heat voltages VCC(est). Compare VCC(est) VCC(max). VCC(est) VCC(max), then reliable operation between VCC(est) VCC(max) requires enhanced RJA. VCC(est) VCC(max), then operation between VCC(est) VCC(max) reliable under these conditions.
example, given common conditions such 25°C, °C/W, then: °C/W 25°C 28°C worst-case estimate, PD(max), represents maximum allowable power level (VCC(max), ICC(max)), without exceeding TJ(max), selected
A3230-DS
Allegro MicroSystems, Inc. Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
A3230
Chopper-Stabilized Hall Effect Bipolar Switch
Package 3-Pin (SOT-23W)
Package 3-Pin
A3230-DS
Allegro MicroSystems, Inc. Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
A3230
Chopper-Stabilized Hall Effect Bipolar Switch
products described herein manufactured under more 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; other patents pending. Allegro MicroSystems, Inc. reserves right make, from time time, such departures from detail specifications required permit improvements performance, reliability, manufacturability products. Before placing order, user cautioned verify that information being relied upon current. Allegro products authorized critical components life-support devices systems without express written approval. information included herein believed accurate reliable. However, Allegro MicroSystems, Inc. assumes responsibility use; infringement patents other rights third parties which result from use. Copyright 2005 Allegro MicroSystems, Inc.
A3230-DS
Allegro MicroSystems, Inc. Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com

Chopper-Stabilized Hall-Effect Bipolar Switch Package 3-pin Surfa

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