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a1381-ds, rev. 1 features and benefits ? customer programmable offset, sensitivity, sensitivity temperature coefficient, and polarity ? programmability at end-of-line ? ratiometric sensitivity, quiescent voltage output, and clamps for interfacing with application dac ? temperature-stable quiescent voltage output and sensitivity ? precise recoverability after temperature cycling ? output voltage clamps provide short circuit diagnostic capabilities ? wide ambient temperature range: ?40c to 150c ? immune to mechanical stress ? miniature package options functional block diagram not to scale a1381, a1382, a1383, and a1384 continued on the next page? packages 3 pin surface mount sot23-w (suffix lh) 3 pin ultramini sip (suffix ua) programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package amp to all subcircuits out vcc v+ vout (programming) gnd filter dynamic offset cancellation gain gain temperature coefficient offset trim control hall drive circuit c bypass description new applications for linear output hall effect sensors, such as displacement, angular position, and current measurement, require high accuracy in conjunction with small package size. the allegro ? a138x family of programmable linear hall effect sensors was designed specifically to achieve both goals. these temperature-stable devices are available in a miniature surface mount package (sot23-w) and an ultramini through- hole single-in-line package. the accuracy of these devices is enhanced via programmability on the output pin for end-of-line optimization without the added complexity and cost of a fully programmable device. these ratiometric hall effect sensors provide a voltage output that is proportional to the applied magnetic field. both the quiescent voltage output and magnetic sensitivity are user- adjustable. the quiescent voltage output can be set around 50% of the supply voltage, and the sensitivity adjusted between 2 mv/g and 9 mv/g over the device family. programming selections also exist for output polarity and temperature compensation. the features of this linear family make it ideal for high accuracy requirements of automotive and industrial applications, and performance is guaranteed over an extended temperature range, ?40c to 150c.
programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package a1381, a1382, a1383, and a1384 2 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com each bicmos monolithic circuit integrates a hall element, temperature-compensating circuitry to reduce the intrinsic sensitivity drift of the hall element, a small-signal high-gain amplifier, a clamped low-impedance output stage, and a proprietary dynamic offset cancellation technique. the a138x sensors are provided in a 3 pin ultramini single-in-line package (ua suffix), and a 3 pin surface mount sot-23w package (lh suffix). absolute maximum ratings characteristic symbol notes rating units forward supply voltage v cc 8v reverse supply voltage v rcc ?0.1 v forward output voltage v out 28 v reverse output voltage v rout ?0.1 v output source current i out(source) vout to gnd 2 ma output sink current i out(sink) vcc to vout 10 ma operating ambient temperature t a range e ?40 to 85 oc range l ?40 to 150 oc storage temperature t stg ?65 to 165 oc maximum junction temperature t j (max) 165 oc description (continued) selection guide part number packing* package t a (c) internal bandwidth (khz) sensitivity range (mv/g) A1381ELHLT-T tape and reel, 3000 pieces/reel surface mount ?40 to 85 12 6.00 to 9.00 a1381eua-t bulk bag, 500 pieces/bag through hole a1381euati-t tape and reel, 2000 pieces/reel a1381llhlt-t tape and reel, 3000 pieces/reel surface mount ?40 to 150 a1381lua-t bulk bag, 500 pieces/bag through hole a1381luati-t tape and reel, 2000 pieces/reel a1382elhlt-t tape and reel, 3000 pieces/reel surface mount ?40 to 85 17 4.00 to 6.25 a1382eua-t bulk bag, 500 pieces/bag through hole a1382euati-t tape and reel, 2000 pieces/reel a1382llhlt-t tape and reel, 3000 pieces/reel surface mount ?40 to 150 a1382lua-t bulk bag, 500 pieces/bag through hole a1382luati-t tape and reel, 2000 pieces/reel a1383elhlt-t tape and reel, 3000 pieces/reel surface mount ?40 to 85 21 2.75 to 4.25 a1383eua-t bulk bag, 500 pieces/bag through hole a1383euati-t tape and reel, 2000 pieces/reel a1383llhlt-t tape and reel, 3000 pieces/reel surface mount ?40 to 150 a1383lua-t bulk bag, 500 pieces/bag through hole a1383luati-t tape and reel, 2000 pieces/reel a1384elhlt-t tape and reel, 3000 pieces/reel surface mount ?40 to 85 27 2.00 to 3.00 a1384eua-t bulk bag, 500 pieces/bag through hole a1384euati-t tape and reel, 2000 pieces/reel a1384llhlt-t tape and reel, 3000 pieces/reel surface mount ?40 to 150 a1384lua-t bulk bag, 500 pieces/bag through hole a1384luati-t tape and reel, 2000 pieces/reel *contact allegro for additional packing options. number name description lh ua 1 1 vcc input power supply; use bypass capacitor to connect to ground 3 2 gnd ground 2 3 vout output signal; also used for programming pin-out diagrams lh package ua package 12 3 12 3
programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package a1381, a1382, a1383, and a1384 3 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com continued on the next page... operating characteristics , valid over full operating temperature range, t a ; c bypass = 0.1 f, v cc = 5 v, unless otherwise specified characteristic symbol test conditions min. typ. max. units electrical characteristics supply voltage v cc 4.5 5.0 5.5 v supply current i cc no load on vout ? 6.9 8 ma power-on time 1 t po a1381 t a = 25 c, c bypass = open, c l (of test probe) = 10 pf, sens = 7.5 mv/g ?32 ? s a1382 t a = 25 c, c bypass = open, c l (of test probe) = 10 pf, sens = 5.0 mv/g ?27 ? s a1383 t a = 25 c, c bypass = open, c l (of test probe) = 10 pf, sens = 3.125 mv/g ?23 ? s a1384 t a = 25 c, c bypass = open, c l (of test probe) = 10 pf, sens = 2.5 mv/g ?19 ? s delay to clamp 1 t clp t a = 25c, c l = 10 nf ? 30 ? s supply zener clamp voltage v z t a = 25c, i cc = 11 ma 6 8.3 ? v internal bandwidth bw i a1381 small signal ?3 db ? 12 ? khz a1382 ? 17 ? khz a1383 ? 21 ? khz a1384 ? 27 ? khz chopping frequency 2 f c t a = 25c ? 170 ? khz output characteristics noise (peak to peak) v n(p-p) a1381 t a =25c; c l = 10 nf, sens = 7.5 mv/g; no external filter ?34 ?mv a1382 t a =25c; c l = 10 nf, sens = 5.0 mv/g; no external filter ?27 ?mv a1383 t a =25c; c l = 10 nf, sens = 3.125 mv/g; no external filter ?20 ?mv a1384 t a =25c; c l = 10 nf, sens = 2.5 mv/g; no external filter ?18 ?mv a138x t a =25c; sens = 2.5 mv/g; external 2 khz low pass filter with r = 1.69 k , c = 47 nf ? 4.7 ? mv dc output resistance r out ?< 1 ? output load resistance r l vout to vcc 4.7 ? ? k vout to gnd 4.7 ? ? k output load capacitance c l vout to gnd ? ? 10 nf phase shift 3 ? no load on vout, magnetic input signal frequency = 1 khz, with 1 v (p-p) output signal ? 3 ? deg. output voltage clamp 4 v clp(high) t a = 25c, b = 600 g, sens = 5.0 mv/g, r l = 10 k (vout to gnd) 4.35 4.5 4.65 v v clp(low) t a = 25c, b = ?600 g, sens = 5.0 mv/g, r l = 10 k (vcc to vout) 0.40 0.55 0.70 v output slew rate sr c l = 10 nf ? 175 ? v/ms
programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package a1381, a1382, a1383, and a1384 4 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com pre-programming target 5 pre-programming quiescent voltage output v out(q)init b = 0 g, t a = 25c ? 2.1 ? v pre-programming sensitivity sens init a1381 t a = 25c ? 4.2 ? mv/g a1382 ? 2.9 ? mv/g a1383 ? 2.1 ? mv/g a1384 ? 1.4 ? mv/g pre-programming sensitivity temperature coefficient 6 tc sensinit t a = 150c ? ?0.05 ? %/c quiescent voltage output programming guaranteed quiescent voltage output range 4,7 v out(q) b = 0 g, t a = 25c 2.3 ? 2.6 v quiescent voltage output programming bits ? 6 ? bit average quiescent voltage output step size 8,9 step vout(q) t a = 25c 8 11.5 15 mv quiescent voltage output programming resolution 10 err pgvout(q) t a = 25c ? step vout(q) 0.5 ?mv sensitivity programming guaranteed sensitivity range 4,11 sens a1381 t a = 25c 6.00 ? 9.00 mv/g a1382 4.00 ? 6.25 mv/g a1383 2.75 ? 4.25 mv/g a1384 2.00 ? 3.00 mv/g sensitivity programming bits ? 6 ? bit average sensitivity step size 8,9 step sens a1381 t a = 25c 90 110 130 v/g a1382 55 75 95 v/g a1383 35 55 75 v/g a1384 28 35 42 v/g sensitivity programming resolution 10 err pgsens t a = 25c ? step sens 0.5 ? mv/g sensitivity tc programming guaranteed sensitivity tem- perature coefficient range 6 tc sens t a = 150c 0.00 ? 0.095 %/c sensitivity temperature coef- ficient programming bits ? 3 ? bit average sensitivity tempera- ture coefficient step size 6 step tcsens t a = 150c ? 0.03 ? %/c sensitivity temperature coeffi- cient programming resolution 6 err pgtcsens t a = 150c ? step tcsens x 0.5 ? %/c polarity programming polarity programming bit 12 pol ? 1 ? bit lock bit programming overall programming lock bit lock ? 1 ? bit operating characteristics (continued) , valid over full operating temperature range, t a ; c bypass = 0.1 f, v cc = 5 v, unless otherwise specified characteristic symbol test conditions min. typ. max. units continued on the next page...
programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package a1381, a1382, a1383, and a1384 5 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com error components linearity sensitivity error lin err ? 1.5 ? % symmetry sensitivity error sym err ? 1.5 ? % ratiometry quiescent voltage output error 13 rat errvout(q) ? 1.5 ? % ratiometry sensitivity error 13 rat errsens ? 1.5 ? % ratiometry clamp error 14 rat errclp t a = 25c ? 1.5 ? % drift characteristics quiescent voltage output drift through temperature range ? v out(q) a1381 t a = 150c ? ? 60 mv a1382 ? ? 50 mv a1383 ? ? 40 mv a1384 ? ? 40 mv sensitivity drift through temperature range 15 ? sens tc ?3 ?% sensitivity drift due to package hysteresis 1 ? sens pkg t a = 25c; after temperature cycling ? 2 ? % 1 see characteristic definitions section. 2 f c varies up to approximately 20% over the full operating ambient temperature range, t a , and process. 3 unit of measure (phase degrees) in reference to the magnetic input signal. 4 sens, v out(q) , v clp(low) , and v clp(high) scale with v cc due to ratiometry. 5 raw device characteristic values before any programming. 6 programmed at 150c and calculated relative to 25c. 7 v out(q) (max) is the value available with all programming fuses blown (maximum programming code set). the v out(q) range is the total range from v out(q)init up to and including v out(q) (max). see characteristic definitions section. 8 step size is larger than required, in order to provide for manufacturing spread. see characteristic definitions section. 9 non-ideal behavior in the programming dac can cause the step size at each significant bit rollover code to be greater than twic e the maximum specified value of step vout(q) , step sens , or step tcsens . 10 overall programming value accuracy. see characteristic definitions section. 11 sens(max) is the value available with all programming fuses blown (maximum programming code set). sens range is the total range from sens init up to and including sens(max). see characteristic definitions section. 12 default polarity is for v out voltage to increase with a positive (south polarity) field applied to the branded face of the device. 13 percent change from actual value at v cc = 5 v, for a given temperature, over the guaranteed supply voltage operating range. 14 percent change from actual value at v cc = 5 v, t a = 25c, over the guaranteed supply voltage operating range. 15 sensitivity drift from expected value at t a after programming tc sens . see characteristic definitions section. operating characteristics (continued) , valid over full operating temperature range,t a ; c bypass = 0.1 f, v cc = 5 v, unless otherwise specified characteristic symbol test conditions min. typ. max. units
programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package a1381, a1382, a1383, and a1384 6 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com thermal characteristics may require derating at maximum conditions, see application information characteristic symbol test conditions* value units package thermal resistance r ja package lh, 1-layer pcb with copper limited to solder pads 228 oc/w package lh, 2-layer pcb with 0.463 in. 2 of copper area each side connected by thermal vias 110 oc/w package ua, 1-layer pcb with copper limited to solder pads 165 oc/w *additional thermal information available on allegro website. 6 5 4 3 2 1 0 20 40 60 80 100 120 140 160 180 temperature (oc) maximum allowable v cc (v) power derating curve (r q ja = 228 oc/w) 1-layer pcb, package lh (r q ja = 110 oc/w) 2-layer pcb, package lh (r q ja = 165 oc/w) 1-layer pcb, package ua v cc(min) v cc(max) 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 20 40 60 80 100 120 140 160 180 temperature (c) power dissipation, p d (mw) power dissipation versus ambient temperature (r q ja = 165 oc/w ) 1-layer pcb, package ua (r q ja = 228 oc/w) 1-layer pcb, pa ckag e lh (r q ja = 110 oc/w ) 2-layer pcb, package lh
programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package a1381, a1382, a1383, and a1384 7 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com characteristic definitions power-on time when the supply is ramped to its operating voltage, the device requires a finite time to power its inter- nal components before responding to an input magnetic field. power-on time, t po , is defined as: the time it takes for the out- put voltage to settle within 10% of its steady state value under an applied magnetic field, after the power supply has reached its minimum specified operating voltage, v cc (min), as shown in the following chart. delay to clamp a large magnetic input step may cause the clamp to overshoot its steady state value. the delay to clamp, t clp , is defined as: the time it takes for the output voltage to settle within 1% of its steady state value, after initially passing through its steady state voltage, as shown in the following chart. quiescent voltage output in the quiescent state (no significant magnetic field: b = 0 g), the output, v out(q) , has a constant ratio to the supply voltage, v cc , throughout the entire operating ranges of v cc and ambient temperature, t a . guaranteed quiescent voltage output range the quiescent voltage output, v out(q) , can be programmed around its nominal value of 2.5 v, within the guaranteed quiescent voltage range limits: v out(q) (min) and v out(q) (max). the available guaran- teed programming range for v out(q) falls within the distributions of the initial, v out(q)init , and the maximum programming code for setting v out(q) , as shown in the following diagram. average quiescent voltage output step size the average qui- escent voltage output step size for a single device is determined using the following calculation: v out(q)maxcode ? v out(q)init 2 n ?1 step vout(q) = . (1) where: n is the number of available programming bits in the trim range, 2 n ?1 is the value of the maximum programming code in the range, and v out(q)maxcode is the quiescent voltage output at code 2 n ?1. quiescent voltage output programming resolution the pro- gramming resolution for any device is half of its programming step size. therefore, the typical programming resolution will be: err pgvout(q) (typ) = 0.5 step vout(q) (typ) . (2) v +t v cc v cc (min.) v out 90% v out 0 t 1 = time at which power supply reaches minimum specified operating voltage t 2 = time at which output voltage settles within 10% of its steady state value under an applied magnetic field t 1 t 2 t po v cc (typ.) v t magnetic input v out 0 t 1 = time at which output voltage initially reaches steady state clamp voltage t 2 = time at which output voltage settles to within 1% of steady state clamp voltage note: times apply to both high clamp (shown) and low clamp. v clp(high) t 1 t 2 t clp v out(q) (max) v out(q) (min) v out(q)init (typ) guaranteed output programming range, v out(q) distribution for max code v out(q) distribution for v out(q)init
programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package a1381, a1382, a1383, and a1384 8 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com quiescent voltage output drift through temperature range due to internal component tolerances and thermal considerations, the quiescent voltage output, v out(q) , may drift from its nominal value over the operating ambient temperature, t a . for purposes of specification, the quiescent voltage output drift through temperature range, ? v out(q) (mv), is defined as: ? v out(q) v out(q)(ta) ? v out(q)(25c) = . (3) sensitivity the presence of a south polarity magnetic field, per- pendicular to the branded surface of the package face, increases the output voltage from its quiescent value toward the supply voltage rail (assuming that the polarity bit, pol, is in its initial state of logic 0). the amount of the output voltage increase is proportional to the magnitude of the magnetic field applied. conversely, the application of a north polarity field decreases the output voltage from its quiescent value. this proportionality is specified as the magnetic sensitivity, sens (mv/g), of the device, and it is defined as: v out(bpos) ? v out(bneg) bpos ? bneg sens = , (4) where bpos and bneg are two magnetic fields with opposite polarities. guaranteed sensitivity range the magnetic sensitivity, sens, can be programmed around its nominal value, 2.5 to 7.5 mv/g depending on device type, within the sensitivity range limits: sens(min) and sens(max). refer to the guaranteed quiescent voltage output range section for a conceptual explanation of how value distributions and ranges are related. average sensitivity step size refer to the average quiescent voltage output step size section for a conceptual explanation. sensitivity programming resolution refer to the quiescent voltage output programming resolution section for a conceptual explanation. sensitivity temperature coefficient device sensitivity changes as temperature changes, with respect to its programmed sensitiv- ity temperature coefficient, tc sens . tc sens is programmed at 150c, and calculated relative to the nominal sensitivity program ming temperature of 25c. tc sens (%/c) is defined as: sens t2 ? sens t1 sens t1 t2?t1 1 tc sens = 100% , ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? (5) where t1 is the nominal sens programming temperature of 25c, and t2 is the tcsens programming temperature of 150c. the ideal value of sens over the full ambient temperature range, sensideal(ta), is defined as: sens t1 [100% + tc sens ( t a ? t1 )] sens ideal(ta) = (6) guaranteed sensitivity temperature coefficient range the magnetic sensitivity temperature coefficient can be programmed within its limits: tc sens (max) and tc sens (min). refer to the guaranteed quiescent voltage output range section for a con- ceptual explanation of how value distributions and ranges are related. average sensitivity temperature coefficient step size refer to the average quiescent voltage output step size section for a conceptual explanation. sensitivity temperature coefficient programming resolution refer to the quiescent voltage output programming resolution section for a conceptual explanation. sensitivity drift through temperature range second order sensitivity temperature coefficient effects cause the magnetic sensitivity, sens, to drift from its ideal value over the operating ambient temperature range, t a . for purposes of specification, the sensitivity drift through temperature range, ? sens tc , is defined as: sens ta ? sens ideal(ta) sens ideal(ta) ? sens tc = 100% . (7) sensitivity drift due to package hysteresis package stress and relaxation can cause the device sensitivity at t a = 25c to change during and after temperature cycling.
programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package a1381, a1382, a1383, and a1384 9 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com for purposes of specification, the sensitivity drift due to package hysteresis, ? sens pkg , is defined as: sens (25c)2 ? sens (25c)1 sens (25c)1 ? sens pkg = 100% , (8) where sens (25c)1 is the programmed value of sensitivity at t a = 25c, and sens (25c)2 is the value of sensitivity at t a = 25c, after temperature cycling t a up to 150c, down to ?40c, and back to up 25c. linearity sensitivity error the 138x family is designed to provide a linear output in response to a ramping applied magnetic field. consider two magnetic fields, b1 and b2. ideally, the sen- sitivity of a device is the same for both fields, for a given supply voltage and temperature. linearity error is present when there is a difference between the sensitivities measured at b1 and b2. linearity error is calculated separately for the positive (lin errpos ) and negative (lin errneg ) applied magnetic fields. linearity error (%) is measured and defined as: sens bpos2 sens bpos1 sens bneg2 sens bneg1 1? lin errpos = 100% , ? ? ? ? ? ? ? ? 1? lin errneg = 100% , ? ? ? ? ? ? ? ? (9) where: |v out(b x ) ? v out(q) | b x sens b x = , (10) and b pos x and b neg x are positive and negative magnetic fields, with respect to the quiescent voltage output such that |b pos2 | > |b pos1 | and |b neg2 | > |b neg1 |. then: lin err max( | lin errpos | , | lin errneg | ) = . (11) symmetry sensitivity error the magnetic sensitivity of an a138x device is constant for any two applied magnetic fields of equal magnitude and opposite polarities. symmetry error, sym err (%), is measured and defined as: sens bpos sens bneg 1? sym err = 100% , ? ? ? ? ? ? ? ? (12) where sens b x is as defined in equation 10, and b pos and b neg are positive and negative magnetic fields such that |b pos | = |b neg |. ratiometry error the a138x devices feature ratiometric output. this means that the quiescent voltage output, v out(q) , magnetic sensitivity, sens, and clamp voltage, v clp(high) and v clp(low) , are proportional to the supply voltage, v cc . in other words, when the supply voltage increases or decreases by a certain percent- age, each characteristic also increases or decreases by the same percentage. error is the difference between the measured change in the supply voltage relative to 5 v, and the measured change in each characteristic. the ratiometric error in quiescent voltage output, rat errvout(q) (%), for a given supply voltage, v cc , is defined as: v out(q)(vcc) / v out(q)(5v) v cc / 5v 1? rat errvout(q) = 100% . ? ? ? ? ? ? ? ? (13) the ratiometric error in magnetic sensitivity, rat errsens (%), for a given supply voltage, v cc , is defined as: sens (vcc) / sens (5v) v cc / 5v 1? rat errsens = 100% . ? ? ? ? ? ? ? ? (14) the ratiometric error in the clamp voltages, rat errclp (%), for a given supply voltage, v cc , is defined as: v clp(vcc) / v clp(5v) v cc / 5v 1? rat errclp = 100% . ? ? ? ? ? ? ? ? (15) where v clp is either v clp(high) or v clp(low) .
programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package a1381, a1382, a1383, and a1384 10 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com amp regulator clock/logic hall element sample and hold low-pass filter concept of chopper stabilization technique when using hall-effect technology, a limiting factor for switchpoint accuracy is the small signal voltage developed across the hall element. this voltage is disproportionally small relative to the offset that can be produced at the output of the hall sensor. this makes it difficult to process the signal while maintaining an accurate, reliable output over the specified operating temperature and voltage ranges. chopper stabilization is a unique approach used to minimize hall offset on the chip. the patented allegro technique, namely dynamic quadrature offset cancellation, removes key sources of the output drift induced by thermal and mechanical stresses. this offset reduction technique is based on a signal modulation-demodulation process. the undesired offset signal is separated from the magnetic field-induced signal in the frequency domain, through modulation. the subsequent demodu- lation acts as a modulation process for the offset, causing the magnetic field-induced signal to recover its original spectrum at base band, while the dc offset becomes a high-frequency signal. the magnetic-sourced signal then can pass through a low-pass filter, while the modulated dc offset is suppressed. the chopper stabilization technique uses a 170 khz high frequency clock. for the demodulation process, a sample and hold technique is used, where the sampling is performed at twice the chopper frequency (340 khz). this high-frequency operation allows a greater sampling rate, which results in higher accuracy and faster signal- processing capability. this approach desensitizes the chip to the effects of thermal and mechanical stresses, and produces devices that have extremely stable quiescent hall output voltages and precise recoverability after temperature cycling. this technique is made possible through the use of a bicmos process, which allows the use of low-offset, low-noise amplifiers in combination with high-density logic integration and sample-and-hold circuits. chopper stabilization technique typical application drawing v+ vcc vout gnd c bypass l c
programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package a1381, a1382, a1383, and a1384 11 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com programming pulse requirements, protocol at t a = 25c characteristic symbol notes min. typ. max. units programming voltage v p(low) measured at the vout pin. - - 5.5 v v p(mid) 14 15 16 v v p(high) 26 27 28 v programming current i p minimum supply current required to ensure proper fuse blowing. in addition, a min- imum capacitance, c blow = 0.1 f, must be connected between the vout and gnd pins during programming to provide the current necessary for fuse blowing. 300 - - ma pulse width t off(high) duration at v p(low) level following a v p(high) level. 30 - - s t off(mid) duration at v p(low) level following a v p(mid) level. 5 - - s t active(high) duration of v p(high) level for v ph pulses during key/code selection. 30 - - s t active(mid) duration of v p(mid) level for v ph pulses during key/code selection. 15 - - s t blow duration at v p(high) level for fuse blowing. 30 - - s pulse rise time t pr rise time required for transitions from v p(low) to either v p(mid) or v p(high) . 1 - 100 s pulse fall time t pf fall time required for transitions from v p(high) to either v p(mid) to v p(low) . 1 - 100 s overview programming is accomplished by sending a series of input volt- age pulses serially through the vout pin of the device. a unique combination of different voltage level pulses controls the internal programming logic of the device to select a desired program- mable parameter and change its value. there are two program- ming pulses, referred to as a high voltage pulse, v ph , consisting of a v p(low) ?v p(high) ?v p(low) sequence and a mid voltage pulse, v pm , consisting of a v p(low) ?v p(mid) ?v p(low) sequence. the 138x features try mode, blow mode, and lock mode: in try mode, the value of a single programmable parameter may be set and measured. the parameter value is stored temporar- ily, and resets after cycling the supply voltage. note that other parameters cannot be accessed simultaneously in this mode. in blow mode, the value of a single programmable parameter may be permanently set by blowing solid-state fuses internal to the device. additional parameters may be blown sequentially. in lock mode, a device-level fuse is blown, blocking the fur- ther programming of all parameters. the programming sequence is designed to help prevent the device from being programmed accidentally; for example, as a result of noise on the supply line. although any programmable variable power supply can be used to generate the pulse waveforms, allegro highly recommends using the allegro sensor evaluation kit, available on the allegro web site on-line store. the manual for that kit is available for download free of charge, and provides additional information on programming these devices. ? ? ? definition of terms register. the section of the programming logic that controls the choice of programmable modes and parameters. bit field. the internal fuses unique to each register, represented as a binary number. incrementing the bit field of a particular register causes its programmable parameter to change, based on the internal programming logic. key . a series of v pm voltage pulses used to select a register, with a value expressed as the decimal equivalent of the binary value. the lsb of a register is denoted as key 1, or bit 0. code . the number used to identify the combination of fuses activated in a bit field, expressed as the decimal equivalent of the binary value. the lsb of a bit field is denoted as code 1, or bit 0. addressing. incrementing the bit field code of a selected register by serially applying a pulse train through the vout pin of the device. each parameter can be measured during the addressing process, but the internal fuses must be blown before the program- ming code (and parameter value) becomes permanent. fuse blowing. applying a v ph voltage pulse of sufficient dura- tion at the v p(high) level to permanently set an addressed bit by blowing a fuse internal to the device. once a bit (fuse) has been blown, it cannot be reset. blow pulse. a v ph voltage pulse of sufficient duration at the v p(high) level to blow the addressed fuse. cycling the supply. powering-down, and then powering-up the supply voltage. cycling the supply is used to clear the program- ming settings in try mode. programming guidelines
programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package a1381, a1382, a1383, and a1384 12 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com figure 1. parameter selection pulse train. this shows the sequence for selecting the register corresponding to key 1, indicated by a single v pm pulse. parameter selection each programmable parameter can be accessed through a specific register. to select a register, a sequence of voltage pulses con- sisting of a v ph pulse, a series of v pm pulses, and a v ph pulse (with no v cc supply interruptions) must be applied serially to the vout pin. the number of v pm pulses is called the key , and uniquely identifies each register. the pulse train used for selec- tion of the first register, key 1, is shown in figure 1. the a138x has three registers that select among the five pro- grammable parameters: register 1: quiescent voltage output, v out(q) register 2: sensitivity, sens register 3: sensitivity temperature coefficient, tc sens polarity, pol overall device locking, lock bit field addressing after a programmable parameter has been selected, a v ph pulse transitions the programming logic into the bit field address- ing state. applying a series of v pm pulses to the vout pin of the device, as shown in figure 2, increments the bit field of the selected parameter. when addressing the bit field, the number of v pm pulses is rep- resented by a decimal number called a code . addressing activates the corresponding fuse locations in the given bit field by incre- menting the binary value of an internal dac. the value of the bit field (and code) increments by one with the falling edge of each v pm pulse, up to the maximum possible code (see the program- ming logic table). as the value of the bit field code increases, the value of the programmable parameter changes. measurements can be taken after each pulse to determine if the desired result for the programmable parameter has been reached. cycling the supply voltage resets all the locations in the bit field that have unblown fuses to their initial states. fuse blowing after the required code is found for a given parameter, its value can be set permanently by blowing individual fuses in the appro- priate register bit field. blowing is accomplished by applying a v ph pulse, called a blow pulse , of sufficient duration at the v p(high) level to permanently set an addressed bit by blowing a fuse internal to the device. due to power requirements, the fuse for each bit in the bit field must be blown individually. to accom- plish this, the code representing the desired parameter value must be translated to a binary number. for example, as shown ? ? ? v+ 0 v p(high) v p(mid) v p(low) code 1 code 2 code 2 n ? 2 code 2 n ? 1 v+ 0 t low t active v p(high) v p(mid) v p(low) figure 2. bit field addressing pulse train. addressing the bit field by incrementing the code causes the programmable parameter value to change. the number of bits available for a given programming code, n , varies among parameters; for example, the bit field for v out(q) has 6 bits available, which allows 63 separate codes to be used. programming procedures
programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package a1381, a1382, a1383, and a1384 13 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com in figure 3, decimal code 5 is equivalent to the binary number 101. therefore bit 2 (code 4) must be addressed and blown, the device power supply cycled, and then bit 0 (code 1) addressed and blown. an appropriate sequence for blowing code 5 is shown in figure 4. the order of blowing bits, however, is not important. blowing bit 0 first, and then bit 2 is acceptable. note: after blowing, the programming is not reversible, even after cycling the supply power. although a register bit field fuse cannot be reset after it is blown, additional bits within the same register can be blown at any time until the device is locked. for example, if bit 1 (binary 10) has been blown, it is still possible to blow bit 0. the end result would be binary 11 (decimal code 3). locking the device after the desired code for each parameter is programmed, the device can be locked to prevent further programming of any parameters. additional guidelines the additional guidelines in this section should be followed to ensure the proper behavior of these devices: a 0.1 f blowing capacitor, c blow , must be mounted between the vout pin and the gnd pin during programming, to ensure enough current is available to blow fuses. the c blow blowing capacitor must be replaced in the final application with a suitable c l . (the maximum load capacitance is 10 nf for proper operation.) the power supply used for programming must be capable of delivering at least 26 v and 300 ma. be careful to observe the t low delay time before powering down the device after blowing each bit. the following programming order is recommended: pol tc sens sens v out(q) lock (only after all other parameters have been pro- grammed and validated, because this prevents any further programming of the device) ? ? ? ? ? 1. 2. 3. 4. 5. figure 4. example of programming pulses applied to the vout pin that result in permanent parameter settings. in this example, the register cor- responding to key 1 is selected and code 5 is addressed and blown. v+ 0 register selection (key 1) v cc = 0 v register selection (key 1) addressing v p(high) v p(mid) v p(low) programming of code 5 in key 1 (code 4) addressing (code 1) (code 4 in key 1) blow t blow (code 1 in key 1) blow v cc = 0 v v cc = 0 v figure 3. example of code 5 broken into its binary components, which are code 4 and code 1. (decimal equivalent) code 5 bit field selection address code format code in binary fuse blowing target bits fuse blowing address code format (binary) 1 0 1 bit 2 bit 0 code 4 code 1 (decimal equivalents)
programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package a1381, a1382, a1383, and a1384 14 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com try mode try mode allows a single programmable parameter to be tested without permanently setting its value. multiple parameters cannot be tested simultaneously in this mode. after powering the vcc supply, select the desired parameter register and address its bit field. when addressing the bit field, each v pm pulse increments the value of the parameter register, up to the maximum possible code (see programming logic table). the addressed parameter value remains stored in the device even after the programming drive voltage is removed from the vout pin, allowing the value to be measured. note that for accurate time measurements, the blow capacitor, c blow , should be removed during output voltage measurement. it is not possible to decrement the value of the register without resetting the parameter bit field. to reset the bit field, and thus the value of the programmable parameter, cycle the supply (v cc ) voltage. blow mode after the required value of the programmable parameter is found using try mode, its corresponding code should be blown to make its value permanent. to do this, select the required parameter register, and address and blow each required bit separately (as described in the fuse blowing section). the supply must be cycled between blowing each bit of a given code. after a bit is blown, cycling the supply will not reset its value. lock mode to lock the device, address the lock bit and apply a blow pulse with c blow in place. after locking the device, no future pro- gramming of any parameter is possible. programming modes
programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package a1381, a1382, a1383, and a1384 15 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com initial state after system power-up, the programming logic is reset to a known state. this is referred to as the initial state. all the bit field locations that have intact fuses are set to logic 0. while in the initial state, any v pm pulses on the vout pin are ignored. to enter the parameter selection state, apply one v ph pulse on the vout pin. parameter selection state this state allows the selection of the parameter register containing the bit fields to be programmed. to select a parameter register, increment through the keys by apply- ing v pm pulses on the vout pin. register keys select among the following programming parameters: 1 pulse - sens 2 pulses - v out(q) 3 pulses - tc sens , pol, and lock to enter the bit field addressing state, apply one v ph pulse on the vout pin. ? ? ? bit field addressing state this state allows the selection of the individual bit fields to be programmed in the selected parameter register (see programming logic table). to leave this state, either cycle device power or blow the fuses for the selected code. note that merely addressing the bit field does not permanently set the value of the selected programming parameter; fuses must be blown to do so. fuse blowing state to blow an addressed bit field, apply a v ph pulse on the vout pin. power to the device should then be cycled before additional programming is attempted. note: each bit representing a decimal code must be blown individually (see the fuse blowing section). programming state machine power-up initial parameter selection bit field addressing fuse blowing v pm v pm =v p(low) ?v p(mid) ?v p(low) v ph =v p(low) ?v p(high) ?v p(low) v pm v pm v pm v pm v pm v pm v pm v pm v ph v ph v ph v ph tc sens , pol, lock v out(q) sens user power-down required 2 1 2 n ? 1 n = total bits in register
programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package a1381, a1382, a1383, and a1384 16 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com programming logic table programmable parameter (register key) bit field address description binary format [msb lsb] decimal equivalent code sens (1) 000000 0 initial value (sens init ) 111111 63 maximum value of sensitivity (sens) in range v out(q) (2) 000000 0 initial value (v out(q)init ) 111111 63 maximum value of quiescent voltage output (v out(q) ) in range; b = 0 g tc sens , pol, lock (3) 000000 0 initial value of sensitivity temperature coefficient range (tc sensinit ) 000111 7 maximum value of sensitivity temperature coef- ficient (tc sens ) in range 001000 8 pol bit, switches polarity (causes v out to increase with a negative [north polarity] field applied to the branded face of the device) 010000 16 lock bit, enables permanent locking of all pro- gramming bit fields in the device
programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package a1381, a1382, a1383, and a1384 17 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com package lh, 3 pin; (sot-23w) 2.40 nom .094 1.00 nom .039 0.70 nom .028 0.15 0.00 .006 .000 1.17 0.75 .046 .030 0.50 0.30 .020 .012 2.10 1.85 .083 .073 3.00 2.70 .118 .106 1.49 nom .059 0.96 nom .038 0.20 0.08 .008 .003 8o 0o 0.60 0.25 .024 .010 3.04 2.80 .120 .110 c seating plane a b 3x 0.20 [.008] m c a b 0.15 [.006] m c a b c 0.10 [.004] 3x 0.95 .037 1.90 .075 0.25 .010 0.95 nom .037 2 1 3 2 1 3 gauge plane seating plane b a b all dimensions reference only, not for tooling use dimensions in millimeters u.s. customary dimensions (in.) in brackets, for reference only (reference jedec to-236 ab, except case width and terminal tip-to-tip) dimensions exclusive of mold flash, gate burrs, and dambar protrusions exact case and lead configuration at supplier discretion within limits shown hall element (not to scale) active area depth 0.28 [.011] c c fits sc?59a solder pad layout; adjust to process requirements a a a
programmable linear hall effect sensors with analog output available in a miniature thin profile surface mount package a1381, a1382, a1383, and a1384 18 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com package ua, 3 pin sip b d d 1.44 .0565 nom .164 .159 4.17 4.04 .122 .117 3.10 2.97 .062 .058 1.57 1.47 .017 .015 0.44 0.38 .019 .014 0.48 0.36 .640 .600 16.26 15.24 .085 max 2.16 .050 nom 1.27 .031 ref 0.79 .0805 nom 2.04 d dimensions in inches metric dimensions (mm) in brackets, for reference only 23 1 a a b c c dambar removal protrusion (6x) active area depth .0195 [0.50] nom d hall element (not to scale); dimensions preliminary ejector mark on opposite side for the latest version of this document, visit our website: www.allegromicro.com copyright ?2007, allegro microsystems, inc. 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 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.

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