FEATURES AN BENEFITS 2 magneic sensing via planar and verical Hall elemens Quadraure oupus 9 phase separaion beween channels ual-channel oupu allows independen use of Z-axis planar Hall in conjuncion wih verical Hall: Y-axis (defaul opion) X-axis (wih -X opion) High sensiiviy, B OP ypically 17 G Auomoive grade AEC-Q1 qualified for use in auomoive applicaions (L emperaure range opion) Oupu shor-circui proecion Resisan o physical sress Reverse-baery proecion Superior emperaure sabiliy Supply volage Zener clamp Small size TYPICAL APPLICATIONS Auomoive Indusrial, Commercial, Blower fans and Consumer Elecric pumps Garage doors Elecronic power Indusrial moors seering Moorized window Sea moors blinds Trunk/lifgae moors Moorized gaes Window/sunroof Pumps moors Whie goods ESCRIPTION The A1262 is a wo channel, laching Hall-effec sensor IC ha feaures boh verical and planar Hall elemens. The verical and planar Hall elemens feaure sensing axes ha are orhogonal o one anoher and provide 9 of phase separaion for ring magnes ha is inherenly independen of magne pole spacing and air gap. The 2 archiecure of he A1262 simplifies he design of moors and magneic encoders by providing quadraure oupu signals in a very small fooprin. The A1262 oupus allow he speed and direcion of a roaing ring magne o be deermined. The A1262 is available in wo sensing opions ha allow flexibiliy in end-sysem magneic design. Boh opions feaure a planar Hall plae ha is sensiive o magneic fields perpendicular o he face of he package (Z). Two opions of verical Hall plae orienaion (X or Y) in boh packages offer flexibiliy in sysem design and magne o sensor placemen. Coninued on he nex page PACKAGES: No o scale 4-Pin SIP (Suffix K) -Pin SOT23W (Suffix LH) V Regulaor To All Subcircuis OUTPUTA X/Y Hall Z Hall ynamic Offse Cancellaion & Muliplexer Amp Low-Pass Filer Sample, Hold &Averaging emuliplexer Curren Limi OUTPUTB Curren Limi Funcional Block iagram GN A1262-S, Rev. 4 MCO-18 July 31, 217
XΔ XΔ A1262 escripion (coninued) On a single silicon chip, he A1262 includes: volage regulaor, reverse baery proecion, wo Hall plaes (one planar and one verical), a muliplexer, a small-signal amplifier, chopper sabilizaion, a Schmi rigger, and wo shor-circui proeced open-drain oupus ha can sink up o 2 ma coninuously. The A1262 is available in wo emperaure ranges: 4 C o 8 C (E emperaure range opion) or 4 C o 1 C (L emperaure range opion). The A1262 is available in a -pin SOT23W surface-moun package (LH) and a 4 pin SIP package (K). Each is offered in wo opions for a variey of magne o sensor orienaions. The packages are RoHS complian and lead (Pb) free, wih 1% mae-in leadframe plaing. SELECTION GUIE Par Number Packing Package Temperaure Range, T A ( C) escripion A1262ELHLT-T 7-in. reel, 3 pieces/reel -pin SOT-23W surface moun A1262ELHLX-T 13-in. reel, 1 pieces/reel -pin SOT-23W surface moun 4 o 8 A1262LK-Y-T Bulk bag, pieces/bag 4-pin SIP hrough-hole 2 Oupus of Y and Z A1262LLHLT-T 7-in. reel, 3 pieces/reel -pin SOT-23W surface moun 4 o 1 A1262LLHLX-T 13-in. reel, 1 pieces/reel -pin SOT-23W surface moun A1262ELHLT-X-T 7-in. reel, 3 pieces/reel -pin SOT-23W surface moun A1262ELHLX-X-T 13-in. reel, 1 pieces/reel -pin SOT-23W surface moun 4 o 8 A1262LK-X-T Bulk bag, pieces/bag 4-pin SIP hrough-hole 2 Oupus of X and Z A1262LLHLT-X-T 7-in. reel, 3 pieces/reel -pin SOT-23W surface moun 4 o 1 A1262LLHLX-X-T 13-in. reel, 1 pieces/reel -pin SOT-23W surface moun RoHS COMPLIANT Terminal Lis Table Number K LH Symbol escripion 1 1 V Connecs power supply o chip 2 2 OUTPUTA Oupu of Z magneic field direcion [1] 1 2 3 4 VCC OUTPUTA OUTPUTB GN Package K, 4-Pin SIP Pinou 3 3 OUTPUTB efaul opion: Oupu of Y magneic field direcion Wih -X opion: Oupu of X magneic field direcion 4 4 GN Ground GN Ground [1] Z-axis recommended for use as he speed channel in a speed and direcion applicaion, due o beer repeaabiliy. ΔZ ΔZ V 1 GN ΔY ΔY 4 GN 1 1 OUTPUTA 2 3 OUTPUTB Package LH, -Pin SOT23W Pinou Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 2
Absolue Maximum Raings Characerisic Symbol Noes Raing Uni Forward Supply Volage V 26. V Reverse Supply Volage V R 16 V Magneic Flux ensiy B Unlimied G Oupu Off Volage V OUT 26. V Oupu Sink Curren I OUT(SINK) Inernally Limied ma Maximum Juncion Temperaure T J(MAX) 16 C For hours 17 C Sorage Temperaure T sg 6 o 17 C THERMAL CHARACTERISTICS: May require deraing a maximum condiions; see applicaion informaion Characerisic Symbol Noes Raing Uni Package Thermal Resisance R θja Package K, single-sided PCB wih copper limied o solder pads 177 C/W Package LH- 4-layer board based on he JEEC sandard 124 C/W * Addiional hermal informaion available on he Allegro websie. Power issipaion, P (mw) 19 18 17 16 1 14 13 12 11 1 9 8 7 6 4 3 2 1 2 4 6 8 1 12 14 16 18 4-Layer PCB, Package LH- (R θja =124ºC/W) Single-Sided PCB, Package K (R θja =177ºC/W) Temperaure ( C) Maximum Power issipaion versus Ambien Temperaure Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 3
ELECTRICAL CHARACTERISTICS: Valid over full operaing volage and T A = 4 C o 8 C (Range E) or T A = 4 C o 1 C (Range L), unless oherwise specified. Characerisics Symbol Tes Condiions Min. Typ. [1] Max. Uni Forward Supply Volage V Operaing, T J < 16 C 4 2 Oupu Leakage Curren I OUTOFF B < B RP 1 µa Oupu On Volage V OUT(SAT) I OUT = 2 ma, B > B OP 18 mv Supply Curren I 2 3 4. ma Reverse-Baery Curren I R V R = 16 V ma Supply Zener Clamp Volage V Z I CC = ma; T A = 2 C 28 34 V Oupu Curren I OUT 2 ma Oupu Shor-Circui Curren Limi I OUT(SINK)LIM T J < T J(max), V OUT = 12 V 3 6 ma Oupu Sink Curren, Peak I OUT(SINK)PK < 3 seconds 11 ma Chopping Frequency f C 8 khz Oupu Rise Time [2][3] r R L = 82 Ω, C S = 2 pf.2 µs Oupu Fall Time [2][3] f R L = 82 Ω, C S = 2 pf.1 µs Power-On Time [2] ON Boh channels, V > V (MIN) 32 48 µs Power-On Sae POS V > V (MIN), < ON Low [1] Typical daa are a T A = 2 C and V =. [2] Power-on ime, rise ime, and fall ime are guaraneed hrough device characerizaion. [3] C S = oscilloscope probe capaciance. Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 4
X X A1262 MAGNETIC CHARACTERISTICS: Valid over full operaing volage and T A = 4 C o 8 C (Range E) or T A = 4 C o 1 C (Range L), unless oherwise specified. Characerisics Symbol Tes Condiions Min. Typ. Max. Uni [4] Operae Poin [] B OP 1 17 4 G Release Poin [] B RP 4 17 1 G Hyseresis B HYS B OP B RP 1 34 68 G Symmery: Channel A, Channel B, B OP(A) + B RP(A), B OP(B) + B RP(B) B SYM(A), B SYM(B) 3 3 G Operae Symmery: B OP(A) B OP(B) B SYM(AB,OP) 2 2 G Release Symmery: B RP(A) B RP(B) B SYM(AB,RP) 2 2 G [4] 1 G (gauss) =.1 mt (milliesla) [] Applicable o all direcions (X/Y and Z). N S N S N S S N S N 1 Y Y S N Z Z The A1262 oupu is urned on when presened wih a souh polariy magneic field beyond B OP in he orienaions illusraed above. The X-axis field response is only applicable o he -X opion; he Y-axis field response is only applicable o he defaul opion. Noe ha magneic polariy beween he LH and K X-axis opions are opposie. Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com
CHARACTERISTIC ATA Supply Curren, I (ma) Average Supply Curren vs. Ambien Temperaure 8 7 6 4 2 3 2 1-6 -4-2 2 4 6 8 1 12 14 16 Supply Curren, I (ma) 8 7 6 4 3 2 1 Average Supply Curren vs. Supply Volage -4 C 2 C 1 C 2 6 1 14 18 22 26 Supply Volage, V (V) Oupu On Volage, V OUT(SAT) (mv) 4 4 3 3 2 2 1 1 Avg. Oupu On Volage vs. Ambien Temperaure -6-4 -2 2 4 6 8 1 12 14 16 VOUT(SAT)-A VOUT(SAT)-B Oupu Leakage Curren, I OUTOFF (µa) 1 8 6 4 2 Avg. Oupu Leakage Curren vs. Ambien Temperaure -6-4 -2 2 4 6 8 1 12 14 16 IOUT(OFF)-A IOUT(OFF)-B Operae Poin, B OP (G) 4 3 3 2 2 1 1 Avg. OUTPUTA Operae Poin vs. Ambien Temperaure -6-4 -2 2 4 6 8 1 12 14 16 2 Operae Poin, B OP (G) 4 3 3 2 2 1 1 Avg. OUTPUTA Operae Poin vs. Supply Volage -4 C 2 C 1 C 2 6 1 14 18 22 26 Supply Volage, V (V) Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 6
CHARACTERISTIC ATA (coninued) Operae Poin, B OP (G) 4 3 3 2 2 1 1 Avg. OUTPUTB Operae Poin vs. Ambien Temperaure -6-4 -2 2 4 6 8 1 12 14 16 2 Operae Poin, B OP (G) 4 3 3 2 2 1 1 Avg. OUTPUTB Operae Poin vs. Supply Volage -4 C 2 C 1 C 2 6 1 14 18 22 26 Supply Volage, V (V) Release Poin, B RP (G) - -1-1 -2-2 -3-3 Avg. OUTPUTA Release Poin vs. Ambien Temperaure -4-6 -4-2 2 4 6 8 1 12 14 16 2 Release Poin, B RP (G) Avg. OUTPUTA Release Poin vs. Supply Volage - -1-1 -2-2 -4 C -3 2 C -3 1 C -4 2 6 1 14 18 22 26 Supply Volage, V (V) Release Poin, B RP (G) - -1-1 -2-2 -3-3 Avg. OUTPUTB Release Poin vs. Ambien Temperaure -4-6 -4-2 2 4 6 8 1 12 14 16 2 Release Poin, B RP (G) Avg. OUTPUTB Release Poin vs. Supply Volage - -1-1 -2-2 -4 C -3 2 C -3 1 C -4 2 6 1 14 18 22 26 Supply Volage, V (V) Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 7
CHARACTERISTIC ATA (coninued) Hyseresis, B HYS (G) 7 6 4 3 2 Avg. OUTPUTA Hyseresis vs. Ambien Temperaure 2 Hyseresis, B HYS (G) 7 6 4 3 2 Avg. OUTPUTA Hyseresis vs. Supply Volage -4 C 2 C 1 C 1-6 -4-2 2 4 6 8 1 12 14 16 1 2 6 1 14 18 22 26 Supply Volage, V (V) Hyseresis, B HYS (G) 7 6 4 3 2 Avg. OUTPUTB Hyseresis vs. Ambien Temperaure 2 Hyseresis, B HYS (G) 7 6 4 3 2 Avg. OUTPUTB Hyseresis vs. Supply Volage -4 C 2 C 1 C 1-6 -4-2 2 4 6 8 1 12 14 16 1 2 6 1 14 18 22 26 Supply Volage, V (V) Avg. B OP(A) +B RP(A) Symmery vs. Ambien Temperaure Avg. B OP(B) +B RP(B) Symmery vs. Ambien Temperaure 1 1 Symmery, B SYM(A) (G) 1 - -1 2 Symmery, B SYM(B) (G) 1 - -1 2-1 -6-4 -2 2 4 6 8 1 12 14 16-1 -6-4 -2 2 4 6 8 1 12 14 16 Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 8
CHARACTERISTIC ATA (coninued) Symmery, B SYM(AB,OP) (G) 1 1 - -1 Avg. B OP(A) B OP(B) Symmery vs. Ambien Temperaure -1-6 -4-2 2 4 6 8 1 12 14 16 2 Symmery, B SYM(AB,RP) (G) 1 1 - -1 Avg. B RP(A) B RP(B) Symmery vs. Ambien Temperaure -1-6 -4-2 2 4 6 8 1 12 14 16 2 Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 9
FUNCTIONAL ESCRIPTION Operaion The oupus of he A1262 swich low (urn on) when he corresponding Hall elemen is presened wih a perpendicular souh magneic field of sufficien srengh. OUTPUTA swiches low if he Z-axis direcion exceeds he operae poin (B OP ), and OUT- PUTB swiches low if he Y-axis direcion (A1262 wih defaul opion) or X-axis direcion (A1262 wih -X opion) exceeds B OP. Afer urn-on, he oupu volage is V OUT(SAT). The device oupus swich high (urn off) when he srengh of a perpendicular norh magneic field exceeds he release poin (B RP ). The difference in he magneic operae and release poins is he hyseresis (B HYS ) of he device. See Figure 1. Removal of he magneic field will leave he device oupu lached on if he las crossed swichpoin is B OP, or lached off if he las crossed swichpoin is B RP. This buil-in hyseresis allows clean swiching of he oupu even in he presence of exernal mechanical vibraion and elecrical noise. The device will power-on in he low oupu sae, even when powering-on in he hyseresis region, beween B OP and B RP. Unlike dual-planar Hall-effec sensors, which have wo planar Hall-effec sensing elemens spaced apar across he widh of he package, boh he verical and planar sensing elemens on he A1262 are locaed in essenially he same locaion on he IC. V OUTPUT V+ Swich o High Swich o Low B- B+ B RP B HYS V OUT(OFF) V OUT(ON) Figure 1: Swiching Behavior of Laches On he horizonal axis, he B+ direcion indicaes increasing souh polariy magneic field srengh, and he B direcion indicaes decreasing souh polariy field srengh (including he case of increasing norh polariy Wih dual-planar Hall sensors, he ring magne mus be properly designed and opimized for he physical Hall spacing (disance) in order o have he oupus of he wo laches o be in quadraure, or 9 degrees ou of phase. Wih he A1262, which uses one planar and one verical Hall-effec sensing elemen, no arge opimizaion is required. When he face of he IC is facing he ring magne, he planar Hall senses he magne poles and he verical Hall senses he ransiion beween poles, herefore he BOP dual planar A1262 ual-planar Sensor A1262 Figure 2: Ring magne opimized for a dual-planar Hall-effec sensor resuling in oupu quadraure also resuls in quadraure for he A1262. Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 1
wo channels will inherenly be in quadraure, irrespecive of he ring-magne pole spacing. Figure 2 above shows a ring magne opimized for he E1-o-E2 spacing of a dual-planar sensor, resuling in quadraure, or 9 degrees phase separaion beween channels. This same arge also resuls in quadraure for he 2 sensing A1262. However when a differen ring magne is used which is no opimized for he E1-o-E2 spacing, he dual-planar sensor exhibis diminished phase separaion, making signal processing he oupus ino speed and direcion less robus. Using a differen ring-magne geomery has no effec on he A1262, and he wo channels remain in quadraure (see Figure 3 below). The relaionship of he various signals and he ypical sysem iming is shown in Figure 4. dual planar A1262 ual-planar Sensor A1262 Figure 3: Ring magne no opimized for a dual-planar Hall-effec sensor resuling in significanly reduced oupu phase separaion, however sill resuls in quadraure for he A1262. Figure 4: Typical Sysem Timing The Planar (P) and Verical (V) signals represen he magneic inpu signal, which is convered o he device oupus, OUTPUTA and OUTPUTB, respecively. While he A1262 does no process he signals ino Speed and irecion, hese could be deermined by he user based on he individual oupu signals. Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 11
2 Oupu Response o a Speed and irecion Par 1 Bx Clockwise Roaion Bz Counerclockwise Roaion Bz Bx Time (s) 4 Bx 3 A1262 Verical Time (s) Planar Time (s) Figure : Typical Sysem Timing The wo acive Hall signals represen he magneic inpu signal, which is convered o he device oupus, OUTPUTA and OUTPUTB. Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 12
Sampling Cycle Channel A Channel B Channel A Channel B Channel A Channel B Channel A Channel B Channel A Channel B B OP(A) B RP(A) B OP(B) B RP(B) Signal OUTPUTA Signal OUTPUTB Sampling Cycle Sampling Cycle Channel B Channel A Channel B Channel A Channel B Channel A Channel B Channel A B OP(A) B OP(A) B RP(A) B RP(A) Signal Signal OUTPUTA OUTPUTA Figure 6: Oupu signal updaing wih respec o he channel sampling The wo acive channels are muliplexed wih a ypical 16 µs sampling period per channel. If he magneic signal crosses he respecive B OP or B RP of a paricular channel, ha channel s oupu will no be updaed unil he end of is sampling period. If he signal crosses he hresholds while he alernae channel is sampling, he updae will occur a he end of he nex sampling period (as long as he signal does no cross back over he hresholds). This is illusraed in Figure 6. The sampling error inroduced by he muliplexing increases wih magneic inpu frequency, which can affec he oupu duy cycle and phase separaion beween oupus. Conac your Allegro represenaive for more informaion regarding suiabiliy o high frequency applicaions. Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 13
A1262 Sensor and Relaionship o Targe The A1262 is available in wo sensing opions: wih Z-axis planar Hall and he Y-axis verical Hall acive (defaul opion), or wih he Z-axis planar Hall and he X-axis verical Hall acive (-X opion). This offers incredible flexibiliy for posiioning he IC wihin various applicaions. The Z-Y opion suppors he radiional configuraion wih he face of he package facing he ring magne (Figure 7a or 7c), wih he axis of roaion going cross he leads, or opposide he leaded side(s) of he package facing he ring magne (Figure 7b or 7d). Figure 7a: LH (-Y opion) Figure 7b: LH (-Y opion) Figure 7c: K (-Y opion) Figure 7d: K (-Y opion) Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 14
The Z-X opion suppors having he IC posiioned wih he face of he package facing he ring magne, and he axis of roaion (Figure 8a or 8c) lenghwise along he package body, or wih eiher of he non-leaded sides of he package facing he ring magne (Figure 8b or 8d). This laer configuraion has he advanage of being able o be mouned exremely close o he ring magne, since here are no leads or solder pads o accommodae for in ha dimension. Figure 8a: LH (-X opion) Figure 8b: LH (-X opion) Figure 8c: K (-X opion) Figure 8d: K (-X opion) Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 1
Power-On Sequence and Timing The saes of OUTPUTA and OUTPUT B are only valid when he supply volage is wihin he specified operaing range (V (MIN) V V (MAX) ) and he power-on ime has elapsed ( > ON ). Refer o Figure 9: Power-On Sequence and Timing for an illusraion of he power-on sequence. V Applicaions I is srongly recommended ha an exernal capacior be conneced (in close proximiy o he Hall sensor) beween he supply and ground of he device o reduce boh exernal noise and noise generaed by he chopper sabilizaion echnique. As shown in Figure 1, a.1 µf capacior is ypical. Planar (Z) V OUT(OFF) V OUT(ON) V Oupu Undefined for V < V (MIN) POS Oupu Responds According o Magneic Field Inpu B > BOP or B < BRP > ON(MAX) ime V S C BYP.1 µf V A1262 OUTPUTA OUTPUTB R LOA R LOA Sensor Oupus Verical (X/Y) V OUT(OFF) V OUT(ON) Oupu Undefined for V < V (MIN) POS Oupu Responds According o Magneic Field Inpu B > BOP or B < BRP > ON(MAX) ime GN GN Figure 1: Typical Applicaion Circui V V (MIN) V ON ime Figure 9: Power-On Sequence and Timing Once he supply volage is wihin he operaional range, he oupus will be in he low sae (power-on sae), irrespecive of he magneic field. The oupus will remain low unil he sensor is fully powered on ( > ON ), a which poin, boh oupus will respond o he corresponding magneic field presened o he sensor (he verical Hall channel ypically responds before he planar Hall channel). Exensive applicaions informaion on magnes and Hall-effec sensors is available in: Hall-Effec IC Applicaions Guide, AN2771, Hall-Effec evices: Guidelines for esigning Subassemblies Using Hall-Effec evices, AN2773.1 Soldering Mehods for Allegro s Producs SM and Through-Hole, AN269 Air-Gap-Independen Speed and irecion Sensing Using he Allegro A1262, AN296124 Improved Speed and irecion Sensing Using Verical Hall Technology, AN29613 All are provided on he Allegro websie: www.allegromicro.com Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 16
Chopper Sabilizaion Technique When using Hall-effec echnology, a limiing facor for swichpoin accuracy is he small signal volage developed across he Hall elemen. This volage is disproporionally small relaive o he offse ha can be produced a he oupu of he Hall sensor. This makes i difficul o process he signal while mainaining an accurae, reliable oupu over he specified operaing emperaure and volage ranges. Chopper sabilizaion is a proven approach used o minimize Hall offse on he chip. The Allegro echnique, namely ynamic Quadraure Offse Cancellaion, removes key sources of oupu drif induced by hermal and mechanical sresses. This echnique is based on a signal modulaion-demodulaion process. The undesired offse signal is separaed from he magneic fieldinduced signal in he frequency domain, hrough modulaion. The subsequen demodulaion acs as a modulaion process for he offse, causing he magneic field induced signal o recover is original specrum a baseband, while he C offse becomes a high-frequency signal. The magneic sourced signal hen can pass hrough a low-pass filer, while he modulaed C offse is suppressed. This configuraion is illusraed in Figure 11. The chopper sabilizaion echnique uses a 4 khz highfrequency clock. For demodulaion process, a sample, hold, and averaging echnique is used, where he sampling is performed a wice he chopper frequency (8 khz). This high-frequency operaion allows a greaer sampling rae, which resuls in higher accuracy and faser signal-processing capabiliy. This approach desensiizes he chip o he effecs of hermal and mechanical sresses, and produces devices ha have exremely sable quiescen Hall oupu volages and precise recoverabiliy afer emperaure cycling. This echnique is made possible hrough he use of a BiCMOS process, which allows he use of low-offse, low-noise amplifiers in combinaion wih high-densiy logic and sample-and-hold circuis. V Muliplexer Amp. Low-Pass Filer Sample, Hold & Averaging Figure 11: Model of Chopper Sabilizaion Technique Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 17
POWER ERATING The device mus be operaed below he maximum juncion emperaure of he device, T J(max). Under cerain combinaions of peak condiions, reliable operaion may require deraing supplied power or improving he hea dissipaion properies of he applicaion. This secion presens a procedure for correlaing facors affecing operaing T J. (Thermal daa is also available on he Allegro MicroSysems websie.) The Package Thermal Resisance (R θja ) is a figure of meri summarizing he abiliy of he applicaion and he device o dissipae hea from he juncion (die), hrough all pahs o he ambien air. Is primary componen is he Effecive Thermal Conduciviy (K) of he prined circui board, including adjacen devices and races. Radiaion from he die hrough he device case (R θjc ) is relaively small componen of R θja. Ambien air emperaure (T A ) and air moion are significan exernal facors, damped by overmolding. The effec of varying power levels (Power issipaion, P ), can be esimaed. The following formulas represen he fundamenal relaionships used o esimae T J a P. P = V IN I IN (1) T = P R θja (2) T J = T A + T (3) For example, given common condiions such as: T A = 2 C, V = 12 V, I = 3 ma, and R θja = 124 C/W for he LH package, hen: P = V I = 12 V 3. ma = 36. mw T = P R θja = 36. mw 124 C/W = 4. C A wors-case esimae (P (max) ) represens he maximum allowable power level (V (max), I (max) ), wihou exceeding T J(max), a a seleced R θja and T A. Example: Reliabiliy for V a T A = 1 C, package LH, using low-k PCB. Observe he wors-case raings for he device, specifically: R θja = 124 C/W, T J(max) = 16 C, V (max) = 2, and I (max) = 7. ma. Calculae he maximum allowable power level (P (max) ). Firs, inver equaion 3: T max = T J(max) T A = 16 C 1 C = 1 C This provides he allowable increase o T J resuling from inernal power dissipaion. Then, inver equaion 2: P (max) = T max R θja = 1 C 124 C/W = 121 mw Finally, inver equaion 1 wih respec o volage: V (es) = P (max) I (max) V (es) = 121 mw 7. ma V (es) = 16.1 V The resul indicaes ha, a T A, he applicaion and device can dissipae adequae amouns of hea a volages V (es). Compare V (es) o V (max). If V (es) V (max), hen reliable operaion beween V (es) and V (max) requires enhanced R θja. If V (es) V (max), hen operaion beween V (es) and V (max) is reliable under hese condiions. T J = T A + T = 2 C + 4. C = 29. C Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 18
PACKAGE OUTLINE RAWINGS 3.43 +.8. 2.16 MAX E1 E 4 E E3 1.32 E3 E 1 2.6.21 +.8..11 2 3 4 B E2 E E1 E.17 E2 E A E E Branded Face E1 E3 1. ±. E2 E 4.84 REF Mold Ejecor Pin Inden NNNN YYWW 1 Sandard Branding Reference View N = evice par number Y = Las wo digis of year of manufacure W = Week of manufacure For Reference Only; no for ooling use (reference WG-91) imensions in millimeers imensions exclusive of mold flash, gae burrs, and dambar prorusions Exac case and lead configuraion a supplier discreion wihin limis shown 14.73 ±.1.41 +.7..38 +.6.3 A B C ambar removal prorusion (8 ) Gae and ie bar burr area Branding scale and appearance a supplier discreion Acive Area eph,.42 mm E Hall Elemens (E1, E2, and E3), no o scale; E2 and E3 are acive in he A1262LK-T; E1 and E3 are acive in he A1262LK-X-T 1.27 NOM Figure 12: Package K, 4-Pin SIP Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 19
For Reference Only No for Tooling Use (Reference WG-969) imensions in millimeers NOT TO SCALE imensions exclusive of mold flash, gae burrs, and dambar prorusions Exac case and lead configuraion a supplier discreion wihin limis shown A Y.11 REF 2.98 +.12.8 AX 1 A Z 4 ±4.18 +.2.3 1 +.1 2.9.2 1.91 +.19.6 2 3 2 8X 12 REF 1.17 REF 3 2. REF Branded Face 3.2 BSC.2 MIN SEATING PLANE GAUGE PLANE 1. ±.13 2.9 BSC. +.1..4 ±.1 1.2 MIN NNN 2.4 A X Acive Area eph, X Axis, 1.49 ±.2 C Sandard Branding Reference View 1. A Y Acive Area eph, Y Axis, 1.4 ±.1 A Z Acive Area eph, Z Axis,.28 ±.4 B.7.9 PCB Reference Layou View B C Reference land paern layou; all pads a minimum of.2 mm from all adjacen pads; adjus as necessary o mee applicaion process requiremens and PCB layou olerances Branding Scale and appearance a supplier discreion Hall Elemens (1, 2, and 3), no o scale; 2 and 3 are acive in he A1262LLH-T; 1 and 3 are acive in he A1262LLH-X-T Figure 13: Package LH, -Pin SOT23-W Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 2
Revision Hisory Number ae escripion Sepember 21, 21 Iniial release 1 February 1, 216 Added E emperaure range opion and magneic swichpoin symmery specificaions 2 February 1, 217 Updaed Feaures and Benefis (page 1), escripion (pages 1-2), Absolue Maximum Raings able (page 3), Elecrical Characerisics able (page 4), Figure (page 12), Figure 6 (page 13), Figure 7 and 8 labels (pages 14-1), Chopper Sabilizaion secion (page 17); added Typical Applicaions; added K package opion; expanded Funcional escripion secion. 3 May 19, 217 Correced Pinou iagrams (page 2). 4 July 31, 217 Updaed Selecion Guide able (page 2). Copyrigh 217, reserves he righ o make, from ime o ime, such deparures from he deail specificaions as may be required o permi improvemens in he performance, reliabiliy, or manufacurabiliy of is producs. Before placing an order, he user is cauioned o verify ha he informaion being relied upon is curren. Allegro s producs are no o be used in any devices or sysems, including bu no limied o life suppor devices or sysems, in which a failure of Allegro s produc can reasonably be expeced o cause bodily harm. The informaion included herein is believed o be accurae and reliable. However, assumes no responsibiliy for is use; nor for any infringemen of paens or oher righs of hird paries which may resul from is use. For he laes version of his documen, visi our websie: www.allegromicro.com Worceser, Massachuses 161-36 U.S.A. 1.8.83.; www.allegromicro.com 21