A3280

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Technical content

NOTE: For detailed information on purchasing options, contact your local Allegro field applications engineer or sales representative. Allegro MicroSystems, Inc. reserves the right to make, from time to time, revisions to the anticipated product life cycle plan for a product to accommodate changes in production capabilities, alternative product availabilities, or market demand. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no respon- sibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use. Recommended Substitutions: Chopper-Stabilized, Precision Hall-Effect Latches A3280, A3281, and A3283 For existing customer transition, and for new customers or new appli- cations, refer to the A1223. Note: The A3280 and A3281 are obsolete. For existing customer transi- tion, and for new customers or new applications, refer to the A1222. Date of status change: August 16, 2010 Deadline for receipt of LAST TIME BUY orders: October 29, 2010 The A3283 part is in production but has been determined to be LAST TIME BUY . This classification indicates that the product is obsolete and notice has been given. Sale of this device is currently restricted to existing customer applications. The device should not be purchased for new design applications because of obsolescence in the near future. Samples are no longer available. Last Time Buy

Description

The A3280, A3281, and A3283 Hall-effect latches are ex treme ly temperature-stable and stress-resistant sensor ICs especially suited for operation over extended temperature ranges to +150°C. Superior high-temperature per for mance is made possible through dynamic offset cancellation, which reduces the residual offset voltage normally caused by device overmolding, temperature dependencies, and thermal stress. The three devices are iden ti cal except for mag net ic switch points. Each device includes on a single silicon chip a voltage regulator, Hall-voltage generator, small-signal amplifier, chopper sta bi li za tion, Schmitt trigger, and a short-circuit protected open-collector output to sink up to 25 mA. A south pole of sufficient strength will turn the output on. A north pole is necessary to turn the output off. An on-board regulator permits operation with supply voltages of 4.2 to 24 volts. Three package styles provide a magnetically op ti mized pack age for most ap pli ca tions. Package type LH is a modified SOT23W surface-mount package, LT is a miniature SOT89/TO-243AA transistor package for surface-mount applications; while UA is a three-lead ultra-mini-SIP for through-hole mounting. Each package type is lead (Pb) free (suffix, –T), with 100% matte tin leadframe plating. 27609.20-DS, Rev. M Features and Benefits ▪ Symmetrical switch points ▪ Resistant to physical stress ▪ Superior temperature stability ▪ Output short-circuit protection ▪ Operation from unregulated supply ▪ Reverse battery protection ▪ Sol id-state reliability ▪ Small size Chopper-Stabilized, Precision Hall-Ef fect Latches Packages: Functional Block Diagram Not to scale A3280, A3281, and A3283 Package LH Package LT Package UA

Chopper-Stabilized, Precision Hall-Effect Latches A3280, A3281 and A3283 2Allegro MicroSystems, Inc.

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A. Selection Guide Part Number Packing* Mounting Ambient, TA (°C) BRP(MIN) (TA = 25°C) (G) BOP(MAX) (TA = 25°C) (G) A3283ELTTR-T 7-in. reel, 1000 pieces/reel SOT89 Surface Mount –40 to 85 –180 180 A3283EUA-T Bulk, 500 pieces/bag 3-pin SIP through hole A3283LLHLT-T 7-in. reel, 3000 pieces/reel SOT23W Surface Mount –40 to 150A3283LLTTR-T 7-in. reel, 1000 pieces/reel SOT89 Surface Mount A3283LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole *Contact Allegro for additional packing options. Absolute Maximum Ratings Characteristic Symbol Notes Rating Units Supply Voltage V CC 26.5 V Reverse Battery Voltage V RCC –30 V Magnetic Flux Density B Unlimited G Output Off Voltage V OUT 26 V Continuous Output Current I OUT Internal current limiting is intended to protect the device from output short circuits. 25 mA Reverse Output Currrent I ROUT –50 mA Operating Ambient Temperature T A Range E –40 to 85 ºC Range L –40 to 150 ºC Maximum Junction Temperature T J(max) 165 ºC Storage Temperature T stg –65 to 170 ºC

Chopper-Stabilized, Precision Hall-Effect Latches A3280, A3281 and A3283 3Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. Suffi x ‘–LH’ Pinning (SOT23W) Suffix '–LT' & '–UA' Pinning (SOT89/TO-243AA & ultra-mini SIP) Dwg. PH-003-2 1SUPPLY VCC GROUND OUTPUT X PTCT

Chopper-Stabilized, Precision Hall-Effect Latches A3280, A3281 and A3283 4Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. ELECTRICAL CHARACTERISTICS over operating temperature range. Limits Characteristic Symbol Test Conditions Min. Typ. Max. Units Supply Voltage Range V CC Operating, T J < 170°C1 4.2 – 24 V Output Leakage Current I OFF V OUT = 24 V, B < BRP – – 10 μA Output Saturation Voltage V OUT(SAT) I OUT = 20 mA, B > BOP – 185 500 mV Output Current Limit I OM B > B OP 30 – 60 mA Power-On Time t po V CC > 4.2 V – – 50 μs Chopping Frequency f C – 340 – kHz Output Rise Time t r R L = 820 , CL = 20 pF – 0.2 2.0 μs Output Fall Time t f R L = 820 , CL = 20 pF – 0.1 2.0 μs Supply Current I CC B < B RP, VCC = 12 V – 3.0 8.0 mA B > B OP, VCC = 12 V – 4.0 8.0 mA Reverse Battery Current I CC V RCC = -30 V – – -5.0 mA Zener Voltage V Z + VD I CC = 15 mA, TA = 25°C 28 32 37 V Zener Impedance z z + zD I CC = 15 mA, TA = 25°C – 50 –  NOTES: 1. Maximum voltage must be adjusted for power dissipation and junction temperature. 2. B OP = operate point (output turns on); BRP = release point (output turns off). 3. Typical Data is at T A = +25°C and VCC = 12 V and is for design information only. Part Numbers1 A3280 A3281 A3283 Operate Point, B OP at T A = +25°C and TA = max. 5.0 22 40 15 50 90 100 150 180 G at T A = -40°C 5.0 – 40 15 – 90 100 – 200 G Release Point, BRP at T A = +25°C and TA = max. -40 -23 -5.0 -90 -50 -15 -180 -150 -100 G Hysteresis, Bhys at T A = +25°C and TA = max. 10 45 80 30 100 180 – 300 360 G (BOP - BRP) at T A = -40°C – – 80 – – 180 – – 360 G NOTES: 1. Complete part number includes a suf fi x to identify operating temperature range (E or L) and package type (LH, LT, or UA). 2. As used here, negative fl ux densities are defi ned as less than zero (algebraic convention) and -50 G is less than +10 G. 3. Typical Data is at TA = +25°C and VCC = 12 V and is for design information only. 4. 1 gauss (G) is exactly equal to 0.1 millitesla (mT). MAGNETIC CHARACTERISTICS over operating voltage range.

Chopper-Stabilized, Precision Hall-Effect Latches A3280, A3281 and A3283 5Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. TYPICAL OPERATING CHARACTERISTICS as a function of temperature

Chopper-Stabilized, Precision Hall-Effect Latches A3280, A3281 and A3283 6Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. TYPICAL OPERATING CHARACTERISTICS as a function of temperature (cont'd) SUPPLY CURRENTOUTPUT SATURATION VOLTAGE 4.0 4.5 5.0 SUPPLY VOLTAGE IN VOLTS 3.0 Dwg. GH-021-1 3.5 RELEASE POINT -40 -80 OPERATE POINT TA = 150°C TA = -40°C 4.0 4.5 5.0 SUPPLY VOLTAGE IN VOLTS 3.0 Dwg. GH-021-3 3.5 RELEASE POINT -20 -40 OPERATE POINT TA = 150°C TA = -40°C 0 25 50 75 100 300 AMBIENT TEMPERATURE IN °C 200 100 -50 Dwg. GH-029-4 150-25 125 IOUT = 20 mA V CC = 12 V 6.0 5.0 4.0 3.0 2.0 0 2 55 07 51 0 0 AMBIENT TEMPERATURE IN °C -50 Dwg. GH-028-5 125-25 150 OUTPUT ON, B > B OP OUTPUT OFF, B < B RP V CC = 12 V A3280* SWITCH POINTS A3281* SWITCH POINTS TYPICAL OPERATING CHARACTERISTICS as a function of supply voltage RP OP

Chopper-Stabilized, Precision Hall-Effect Latches A3280, A3281 and A3283 7Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. TYPICAL OPERATING CHARACTERISTICS as a function of supply voltage (cont’d) 4.0 4.5 5.0 SUPPLY VOLTAGE IN VOLTS 3.0 Dwg. GH-055-1 3.5 24 TA = 150°C TA = +25°C TA = -40°C IOUT = 20 mA 250 150 200 225 175 4.0 6.0 9.0 SUPPLY VOLTAGE IN VOLTS 3.0 Dwg. GH-058-4 5.0 12 TA = 150°C TA = +25°C TA = -40°C 7.0 5.0 3.0 1.0 6.0 4.0 2.0 8.0 OUTPUT ON 10 118.07.0 SUPPLY CURRENT OUTPUT SATURATION VOLTAGE

Chopper-Stabilized, Precision Hall-Effect Latches A3280, A3281 and A3283 8Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. FUNCTIONAL DESCRIPTION Chopper-Stabilized Technique. The Hall element can be considered as a resistor array similar to a Wheatstone bridge. A large portion of the offset is a result of the mismatching of these resistors. These devices use a proprietary dynamic offset cancel- lation technique, with an internal high-frequency clock to reduce the residual offset voltage of the Hall element that is normally caused by device overmolding, temperature de pen den cies, and thermal stress. The chopper-stabilizing technique cancels the mismatching of the resistor circuit by changing the direction of the current fl owing through the Hall plate using CMOS switches and Hall voltage measurement taps, while maintaing the Hall- voltage signal that is induced by the external magnetic fl ux. The signal is then captured by a sample-and-hold circuit and further processed using low-offset bipolar circuitry. This technique produces devices that have an extremely stable quiescent Hall output voltage, are immune to thermal stress, and have precise recoverability after temperature cycling. This technique will also slightly degrade the device output repeatability. A relatively high sampling frequency is used in order that faster signals can be processed. More detailed descriptions of the circuit operation can be found in: Technical Paper STP 97-10, Monolithic Magnetic Hall Sensing Using Dynamic Quadrature Offset Cancellation and Technical Paper STP 99-1, Chopper-Stabilized Amplifi ers With A Track-and-Hold Signal Demodulator. Operation. The output of these devices switch es low (turns on) when a magnetic fi eld perpendicular to the Hall element exceeds the operate point threshold (B OP). After turn-on, the output is capable of sinking 25 mA and the output voltage is V OUT(SAT). Note that the de vice latch es; that is, a south pole of suffi cient strength towards the branded surface of the device will turn the device on; removal of the south pole will leave the device on. When the magnetic fi eld is reduced below the release point (B RP), the device output goes high (turns off). The dif fer- ence in the magnetic operate and release points is the hysteresis hys) of the device. This built-in hysteresis allows clean switch- ing of the output even in the presence of external mechanical vibration and electrical noise. Powering up in the absence of a magnetic fi eld (less than B OP and higher than BRP) will allow an indeterminate output state. The correct state is warranted after the fi rst excursion beyond BOP or BRP. It is strongly recommended that an external bypass ca pac i tor

Chopper-Stabilized, Precision Hall-Effect Latches A3280, A3281 and A3283 9Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. be con nect ed (in close proximity to the Hall element) between the supply and ground of the device to reduce both external noise and noise generated by the chopper-sta bi li za tion tech nique. The sim plest form of magnet that will op er ate these devices is a ring magnet. Oth er meth ods of operation, such as linear mag- nets, are possible. Extensive applications information for Hall-effect devices is available in:

• Hall-Effect IC Applications Guide, Application Note 27701;
• Guidelines for Designing Subassemblies Using Hall-Effect De- vices, Application Note 27703.1 More detailed descriptions of the chopper-stabilized circuit opera- tion can be found in:
• Monolithic Magnetic Hall Sensing Using Dynamic Quadrature Offset Cancelation, Technical Paper STP 97-10; and
• Chopper-Stabilized Amplifi ers With A Track-and-Hold Signal Demodulator, Technical Paper STP 99-1. All are provided at www.allegromicro.com APPLICATIONS INFORMATION SUPPLY OUTPUT Dwg. EH-013 0.1 MF SUPPLY VCC X PTCT

Chopper-Stabilized, Precision Hall-Effect Latches A3280, A3281 and A3283 10Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. Package LH, 3-Pin (SOT-23W)

0.55 REF

0.25 BSC

0.95 BSC

0.95 1.00 0.70 2.40 A Active Area Depth, 0.28 mm REF B C C B Reference land pattern layout All pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary to meet application process requirements and PCB layout tolerances Branding scale and appearance at supplier discretion A PCB Layout Reference View Standard Branding Reference View Branded Face N = Last two digits of device part number T = Temperature code NNT 2.90 +0.10 –0.20 8X 10° REF 0.180+0.020 –0.053 0.05 +0.10 –0.05

0.25 MIN

1.91 +0.19 –0.06 2.98 +0.12 –0.08 1.00 ±0.13 0.40 ±0.10 4°±4° For Reference Only; not for tooling use (reference dwg. 802840) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown D Hall element, not to scale D D D1.49 0.96

Chopper-Stabilized, Precision Hall-Effect Latches A3280, A3281 and A3283 11Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. Parting Line 2.24 1.14 321 A A Active Area Depth, 0.78 mm REF B C D C 2X 1.50 BSC 4.50±0.10 1.50±0.10 0.50±0.06 0.42±0.06 1.73 +0.10 –0.11 2.20 +0.09 –0.072.45 +0.15 –0.164.10 +0.15 –0.16 1.00 +0.20 –0.11 0.40 +0.04 –0.05 Branding scale and appearance at supplier discretion Hall element, not to scale Reference land pattern layout (reference IPC7351 SOT89N); All pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary to meet application process requirements and PCB layout tolerances Standard Branding Reference View NNT = Supplier emblem N = Last two digits of device part number T = Temperature code For Reference Only; not for tooling use (reference JEDEC. TO-243AA) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown 1.50 1.00 0.80 2.60 2.00 2.50 0.70 4.60 B PCB Layout Reference View Basic pads for low-stress, not self-aligning Additional pad for low-stress, self-aligning Additional area for IPC reference layout

Chopper-Stabilized, Precision Hall-Effect Latches A3280, A3281 and A3283 12Allegro MicroSystems, Inc. Worcester, Massachusetts 01615-0036 U.S.A. Copyright ©2002-2010, Allegro MicroSystems, Inc. Allegro MicroSystems, Inc. reserves the right to make, from time to time, such de par tures from the detail spec i fi ca tions as may be required to per- mit improvements in the per for mance, 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’s products are not to be used in life support devices or systems, if a failure of an Allegro product can reasonably be expected to cause the failure of that life support device or system, or to affect the safety or effectiveness of that device or system. The in for ma tion in clud ed herein is believed to be ac cu rate and reliable. How ev er, Allegro MicroSystems, Inc. assumes no re spon si bil i ty for its use; nor for any in fringe ment of patents or other rights of third parties which may result from its use. For the latest version of this document, visit our website: www.allegromicro.com Package UA, 3-Pin SIP 231

1.27 NOM

2.16 MAX 0.51 REF 45° C 45°

0.79 REF

B E E E 2.06 1.45 Gate burr area A B C Dambar removal protrusion (6X) A D E D Branding scale and appearance at supplier discretion Hall element, not to scale Active Area Depth, 0.50 mm REF For Reference Only; not for tooling use (reference DWG-9049) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown Standard Branding Reference View = Supplier emblem N = Last two digits of device part number T = Temperature code NNT Mold Ejector Pin Indent Branded Face 4.09 +0.08 –0.05 0.41 +0.03 –0.06 3.02 +0.08 –0.05 0.43 +0.05 –0.07 15.75 ±0.51 1.52 ±0.05