View ATS625LSGTN-T3_2859213.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

gnd vout vcc ppeak output transistor current limit 0.1 f c bypass v+ voltage regulator aux hall amp automatic gain control v proc pdac ndac reference generator npeak pthresh nthresh threshold logic threshold comparator (recommended) description the ats625 true zero-speed gear tooth sensor is an optimized hall ic and magnet configuration packaged in a molded module that provides a manufacturer-friendly solution for digital gear tooth sensing applications. the sensor assembly consists of an over-molded package that holds together a samarium cobalt magnet, a pole piece concentrator, and a true zero-speed hall ic that has been optimized to the magnetic circuit. this small package can be easily assembled and used in conjunction with gears of various shapes and sizes. the sensor incorporates a dual-element hall ic that switches in response to differential magnetic signals created by a ferrous target. digital processing of the analog signal provides zero- speed performance independent of air gap as well as dynamic adaptation of device performance to the typical operating conditions found in automotive applications (reduced vibration sensitivity). high-resolution peak detecting dacs are used to set the adaptive switching thresholds of the device. switchpoint hysteresis reduces the negative effects of any anomalies in the magnetic signal associated with the targets used in many automotive applications. this sensor system is optimized ats625lsg-ds, rev. 2 features and benefits ? highly repeatable over operating temperature range ? tight timing accuracy over operating temperature range ? true zero-speed operation ? air-gap?independent switchpoints ? vibration immunity ? large operating air gaps ? defined power-on state ? wide operating voltage range ? digital output representing target profile ? single-chip sensing ic for high reliability true zero-speed low-jitter high accuracy gear tooth sensor continued on the next page? functional block diagram not to scale package: 4 pin sip (suffix sg) ats625lsg continued on the next page?
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 2 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com selection guide part number pb-free 1 packing 2 ats625lsgtn-t 3 yes tape and reel 13-in. 800 pcs./reel 1 pb-based variants are being phased out of the product line. certain variants cited in this footnote are in production but have been determined to be not for new design. this classification indicates that sale of this device is currently restricted to existing customer applications. the device should not be purchased for new design applications because obsolescence in the near future is probable. samples are no longer available. status change: may 1, 2006. these variants include: ats625lsgtn 2 contact allegro for additional packing options. 3 some restrictions may apply to certain types of sales. contact allegro for details. ? small mechanical size ? optimized hall ic magnetic system ? fast start-up ? agc and reference adjust circuit ? undervoltage lockout features and benefits (continued) description (continued) for crank applications that utilize targets that possess signature regions. theats625 is provided in a 4-pin sip. the pb (lead) free option, available by special request, has a 100% matte tin plated leadframe. absolute maximum ratings characteristic symbol notes rating units supply voltage v cc see power derating section 26.5 v reverse-supply voltage v rcc ?18 v reverse-supply current i rcc 50 ma reverse-output voltage v rout ?0.5 v output sink current i out 10 ma operating ambient temperature t a range l ?40 to 150 oc maximum junction temperature t j (max) 165 oc storage temperature t stg ?65 to 170 oc terminal list name description number vcc connects power supply to chip 1 vout output from circuit 2 aux for allegro use only 3 gnd ground 4 24 3 1
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 3 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com electrical characteristics supply voltage v cc operating; t j < t jmax 4.0 ? 24 v undervoltage lockout v ccuv ? ? < v cc(min) v reverse supply current i rcc v cc = ?18 v ? ? ?10 ma supply zener clamp voltage 1 v z i cc = 17 ma 28 ? ? v supply zener current 2 i z v s = 28 v ? ? 17 ma supply current i cc output off ? 8.5 14 ma output on ? 8.5 14 ma power-on characteristics power-on state s po ? high ? v power-on time t po gear speed < 100 rpm; v cc > v cc min ? ? 200 s output stage low output voltage v out(sat) i sink = 20 ma, output = on ? 200 450 mv output current limit i out(lim) v out = 12 v, t j < t jmax 25 45 70 ma output leakage current i out(off) output = off, v out = 24 v ? ? 10 a output rise time t r r l = 500 , c l = 10 pf ? 1.0 2 s output fall time t f r l = 500 , c l = 10 pf ? 0.6 2 s switchpoint characteristics speed s reference target 60+2 0 ? 12000 rpm bandwidth bw corresponds to switching frequency ? 3 db ? 20 ? khz operate point b op % of peak-to-peak signal, ag < ag max ; b in transitioning from low to high ?60 ? % release point b rp % of peak-to-peak signal, ag < ag max ; b in transitioning from high to low ?40 ? % calibration initial calibration 3 cal po start-up ? 1 6 edges calibration update cal running mode operation continuous ? operating characteristics valid at t a = ?40c to 150c, t j t j(max) , over full range of ag, unless otherwise noted; typical operating parameters: v cc = 12 v and t a = 25c characteristic symbol test conditions min. typ. max. units continued on the next page...
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 4 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com operating characteristics with 60+2 reference target operational air gap ag measured from sensor branded face to target tooth 0.5 ? 2.5 mm relative timing accuracy, sequen- tial mechanical rising edges err rr relative to measurement taken at ag = 1.5 mm ? ? 0.4 deg. relative timing accuracy, sequen- tial mechanical falling edges err ff relative to measurement taken at ag = 1.5 mm ? ? 0.4 deg. relative timing accuracy, signa- ture mechanical rising edge 4 err sigr relative to measurement taken at ag = 1.5 mm ? ? 0.4 deg. relative timing accuracy, signa- ture mechanical falling edge 5 err sigf relative to measurement taken at ag = 1.5 mm ? ? 1.5 deg. relative repeatability, sequential rising and falling edges 6 t e 360 repeatability, 1000 edges; peak-peak sinusoidal signal with b peak b in(min) and 6 period ? ? 0.08 deg. operating signal 7 b in ag (min) < ag < ag (max) 60 ? ? g 1 test condition is i cc(max) + 3 ma. 2 upper limit is i cc(max) + 3 ma. 3 power-on speed 200 rpm. refer to the sensor description section for information on start-up behavior. 4 detection accuracy of the update algorithm for the first rising mechanical edge following a signature region can be adversely affected by the magnetic bias of the signature region. please consult with allegro field applications engineering for aid with assessment of specific ta rget geometries. 5 detection accuracy of the update algorithm for the falling edge of the signature region is highly dependent upon specific targ et geometry. please consult with allegro field applications engineering for aid with assessment of specific target geometries. 6 the repeatability specification is based on statistical evaluation of a sample population. 7 peak-to-peak magnetic flux strength required at hall elements for complying with operational characteristics. operating characteristics, continued valid at t a = ?40c to 150c, t j t j(max) , over full range of ag, unless otherwise noted; typical operating parameters: v cc = 12 v and t a = 25c characteristic symbol test conditions min. typ. max. units
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 5 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com reference target 60+2 characteristics symbol test conditions typ. units symbol key outside diameter d o outside diameter of target 120 mm t,t sig t v ? d o h t f branded face of sensor air gap face width f breadth of tooth, with respect to sensor 6mm circular tooth length t length of tooth, with respect to sensor; measured at d o 3mm signature region cir- cular tooth length t sig length of signature tooth, with respect to sensor; mea- sured at d o 15 mm circular valley length t v length of valley, with respect to sensor; measured at d o 3mm tooth whole depth h t 3mm material low carbon steel ? ? reference target signature region 60+2 of sensor branded face pin 4 pin 1 reference target (gear) information for the generation of adequate magnetic field levels, the fol- lowing recommendations should be followed in the design and specification of targets: ? 2 mm < tooth width, t < 4 mm ? valley width, t v > 2 mm ? valley depth, h t > 2 mm ? tooth thickness, f 3 mm ? target material must be low carbon steel although these parameters apply to targets of traditional geometry (radially oriented teeth with radial sensing, shown in figure 1), they also can be applied in applications using stamped targets (an aperture or rim gap punched out of the target mate- rial) and axial sensing. for stamped geometries with axial sens- ing, the valley depth, h t , is intrinsically infinite, so the criteria for tooth width, t, valley width, t v , tooth material thickness, f, and material specification need only be considered for reference. for example, f can now be < 3 mm. figure 1. configuration with radial-tooth reference target
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 6 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com characteristic data: electrical 0 5 10 15 20 25 30 -50 -25 0 25 50 75 100 125 150 175 0 5 10 15 20 25 30 -50 -25 0 25 50 75 100 125 150 175 -50 -25 0 25 50 75 100 125 150 175 -50 -25 0 25 50 75 100 125 150 175 current (ma) current (ma) current (ua) current (ma) current (ma) voltage (mv) i cc(on) versus v cc i cc(off) versus v cc i cc(on) versus t a i cc(off) versus t a i out(off) versus t a v out(sat) versus t a voltage (v) temperature (c) voltage (v) temperature (c) temperature (c) temperature (c) 5 6 7 8 9 10 11 12 13 14 5 6 7 8 9 10 11 12 13 14 -10 -8 -6 -4 -2 0 2 4 6 8 10 5 6 7 8 9 10 11 12 13 14 5 6 7 8 9 10 11 12 13 14 0 50 100 150 200 250 300 350 400 vcc = 26.5v vcc = 20v vcc = 12v vcc = 4v vcc = 24v vcc = 20v vcc = 12v vcc = 4v i out (ma) 25 20 15 10 5 v cc (v) 26.5 20.0 12.0 4.0 v cc (v) 24.0 20.0 12.0 4.0 v out (v) 26.5 20.0 12.0 4.0 t a (c) -40 0 25 85 150 t a (c) -40 0 25 85 150
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 7 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com characteristic data: relative timing accuracy relative timing accuracy versus speed -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 0 500 1000 1500 2000 2500 edge position () relative timing accuracy versus ambient signature tooth rising edge 0.5 mm air gap -50 0 50 100 150 200 temperature, t a (c) edge position () -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 edge position () signature tooth falling edge 0.5 mm air gap -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 temperature, t a (c) edge position () -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 edge position () rising edge following signature tooth 0.5 mm air gap -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 temperature, t a (c) edge position () -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 -50 0 50 100 150 200 -50 0 50 100 150 200 0 500 1000 1500 2000 2500 0 500 1000 1500 2000 2500 target speed, s (rpm) target speed, s (rpm) target speed, s (rpm) relative timing accuracy versus speed relative timing accuracy versus speed relative timing accuracy versus ambient relative timing accuracy versus ambient signature tooth rising edge 0.5 mm air gap signature tooth falling edge 0.5 mm air gap rising edge following signature tooth 0.5 mm air gap t a (c) ?40 0 25 85 150 t a (c) ?40 0 25 85 150 t a (c) ?40 0 25 85 150 s (rpm) 50 100 500 1000 1500 2000 s (rpm) 50 100 500 1000 1500 2000 s (rpm) 50 100 500 1000 1500 2000
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 8 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com relative timing accuracy versus speed -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 0 500 1000 1500 2000 2500 edge position () relative timing accuracy versus ambient signature tooth rising edge 2.5 mm air gap -50 0 50 100 150 200 temperature, t a (c) edge position () -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 edge position () signature tooth falling edge 2.5 mm air gap -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 temperature, t a (c) edge position () -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 edge position () rising edge following signature tooth 2.5 mm air gap -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 temperature, t a (c) edge position () -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 -50 0 50 100 150 200 -50 0 50 100 150 200 0 500 1000 1500 2000 2500 0 500 1000 1500 2000 2500 target speed, s (rpm) target speed, s (rpm) target speed, s (rpm) relative timing accuracy versus speed relative timing accuracy versus speed relative timing accuracy versus ambient relative timing accuracy versus ambient signature tooth rising edge 2.5 mm air gap signature tooth falling edge 2.5 mm air gap rising edge following signature tooth 2.5 mm air gap t a (c) ?40 0 25 85 150 t a (c) ?40 0 25 85 150 t a (c) ?40 0 25 85 150 s (rpm) 50 100 500 1000 1500 2000 s (rpm) 50 100 500 1000 1500 2000 s (rpm) 50 100 500 1000 1500 2000
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 9 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com signature tooth rising edge t a = ?40, 0, 25, 85, 150 (c) -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 air gap (mm) edge position () -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 air gap (mm) edge position () rising edge following signature tooth -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 0 0.5 1.0 1.5 2.0 2.5 3.0 air gap (mm) edge position () 360 repeatability versus air gap sequential tooth falling edge 0 0.05 0.10 0.15 0.20 0.25 0 1.0 2.0 3.0 4.0 repeatabilty () relative timing accuracy versus air gap relative timing accuracy versus air gap s = 50, 100, 500, 1000, 1500, 2000 (rpm) signature tooth falling edge relative timing accuracy versus air gap t a = ?40, 0, 25, 85, 150 (c) s = 50, 100, 500, 1000, 1500, 2000 (rpm) t a = ?40, 0, 25, 85, 150 (c) s = 50, 100, 500, 1000, 1500, 2000 (rpm) s = 1000 rpm air gap (mm) ?40 25 150 t a (c) characteristic data: repeatability
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 10 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com sensor description figure 2. device cross section. relative motion of the target is detected by the dual hall elements mounted on the hall ic. this view is from the side opposite the pins. figure 3. this left-to-right (pin 1 to pin 4) direction of target rotation results in a high output signal when a tooth of the target gear is centered over the face of the sensor. a right-to-left (pin 4 to pin 1) rotation inverts the output signal polarity. target (gear) back-biasing magnet south pole north pole plastic ( pin 1 side ) ( pin n >1 side ) hall ic pole piece element pitch (concentrator) dual-element hall effect device hall element 1 hall element 2 of sensor rotating target branded face 1 4 assembly description the ats625lsg true zero-speed gear tooth sensor is a com- bined hall ic-magnet configuration that is fully optimized to provide digital detection of gear tooth edges. this sensor is integrally molded into a plastic body that has been optimized for size, ease of assembly, and manufacturability. high operating temperature materials are used in all aspects of construction. sensing technology the gear tooth sensor contains a single-chip differential hall effect sensor ic, a 4-pin leadframe, a samarium cobalt magnet, and a flat ferrous pole piece. the hall ic consists of two hall elements spaced 2.2 mm apart, and each independently measures the magnetic gradient created by the passing of a ferrous object. this is illustrated in figures 2 and 3. the differential output of the two elements is converted to a digital signal that is processed to provide the digital output. switching description after proper power is applied to the component, the sensor is then capable of providing digital information that is representa- tive of the profile of a rotating gear, as illustrated in figure 4. no additional optimization is needed and minimal processing circuitry is required. this ease of use reduces design time and incremental assembly costs for most applications. figure 4. the magnetic profile reflects the geometry of the target, allowing the device to present an accurate digital output r esponse. target mechanical profile target magnetic profile sensor out put electrical profile target motion from pin 1 to pin 4 sensor out put electrical profile target motion from pin 4 to pin 1 signature tooth b+ b in v+ v out v+ v out sensor output switch state on off on off on off on off on off on off on off on off
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 11 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com undervoltage lockout when the supply voltage falls below the undervoltage lockout level, v ccuv , the device switches to the off state. the device remains in that state until the voltage level is restored to to the v cc operating range. changes in the target magnetic profile have no effect until voltage is restored. this prevents false sig- nals caused by undervoltage conditions from propagating to the output of the sensor. power supply protection the device contains an on-chip regulator and can operate over a wide range of supply voltage levels. for applications using an unregulated power supply, transient protection must be added externally. for applications using a regulated supply line, emi and rfi protection may still be required. the circuit shown in figure 5 is the basic configuration required for proper device operation. contact allegro field applications engineering for information on the circuitry required for compliance to various emc specifications. internal electronics the ats625lsg contains a self-calibrating hall effect ic that possesses two hall elements, a temperature compensated amplifier and offset cancellation circuitry. the ic also contains a voltage regulator that provides supply noise rejection over the operating voltage range. the hall transducers and the electron- ics are integrated on the same silicon substrate by a proprietary bicmos process. changes in temperature do not greatly affect this device due to the stable amplifier design and the offset rejec- tion circuitry. 4 vcc v s sensor output gnd vout aux c bypass 0.1 f r pu ats625 1 2 3 figure 5. power supply protection typical circuit
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 12 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com sensor operation description power-on state at power-on, the device is guaranteed to initialize in the off state, with v out high. first edge detection the device uses the first two mechanical edges to synchronize with the target features (tooth or valley) and direction of rotation of the target. the device is synchonized by the third edge. the actual behavior is affected by: target rotation direction relative to the, target feature (tooth, rising edge, falling edge, or valley) that is centered on the device at power-on, and fact that the sensor powers-on in the off state,with v out high, regardless of the eventual direction of target rotation. the interaction of these fac- tors results in a number of possible power-on scenarios. these are diagrammed in figure 6. in all start-up scenarios, the correct number of output edges is provided, but the accuracy of the first two edges may be compromised. target mechanical profile sensor output, v out (start-up over valley) target magnetic profile (start-up over tooth) (start-up over rising edge) (start-up over falling edge) target mechanical profile sensor output, v out (start-up over valley) target magnetic profile (start-up over tooth) (start-up over rising edge) (start-up over falling edge) sensor start-up location sensor start-up location sensor pin 4 side sensor pin 1 side target motion relative to sensor sensor pin 1 side sensor pin 4 side target motion relative to sensor (a) target relative movement as shown in figure 3. output signal is high over the tooth. (b) target relative movement opposite that shown in figure 3. output signal is low over the tooth. figure 6. start-up position and relative motion effects on first device output switching. panel a shows the effects when the target is moving from pin 1 toward pin 4 of the device; v out goes high at the approach of a tooth. when the target is moving in the opposite direction, as in panel b, the polarity of the device output inverts; v out goes low at the approach of a tooth.
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 13 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com agc (automatic gain control) the agc feature is implemented by a unique patented self- calibrating circuitry. after each power-on, the device measures the peak-to-peak magnetic signal. the gain of the sensor is then adjusted, keeping the internal signal amplitude constant over the air gap range of the device, ag. this feature ensures that opera- tional characteristics are isolated from the effects of changes in ag. the effect of agc is shown in figure 7. differential electrical signal versus target rotation at various air gaps, without agc differential electrical signal versus target rotation at various air gaps, with agc 0.25 mm ag: 0.50 mm 1.00 mm 1.50 mm 2.00 mm 0.25 mm ag: 0.50 mm 1.00 mm 1.50 mm 2.00 mm target rotation () differential signal, v proc (mv) -1000 -800 -600 -400 -200 0 200 400 600 800 1000 0 3 6 9 12 15 18 21 24 target rotation () differential signal, v proc (mv) -1000 -800 -600 -400 -200 0 200 400 600 800 1000 0 3 6 9 1215182124 offset adjustment in addition to normalizing performance over varying ag, the gain control circuitry also reduces the effect of chip, magnet, and installation offsets. this is accomplished using two dacs (d to a converters) that capture the peaks and valleys of the processed signal, v proc , and use it as a reference for the thresh- old comparator subcircuit, which controls device switching. if induced offsets bias the absolute signal up or down, agc and the dynamic dac behavior work to normalize and reduce the impact of the offset on sensor performance. figure 7. effect of agc. the left panel shows the process signal, v proc , without agc. the right panel shows the effect with agc. the result is a normalized v proc , which allows optimal performance by the rest of the circuits that reference this signal.
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 14 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com switchpoints switchpoints in the ats625 are a percentage of the amplitude of the signal, v proc , after normalization with agc. in operation, the actual switching levels are determined dynamically. two dacs track the peaks of v proc (see the update subsection). the switching thresholds are established at 40% and 60% of the values held in the two dacs. the proximity of the thresholds near the 50% level ensures the most accurate and consistent switching, because it is where the slope of v proc is steepest and least affected by air gap variation. the low hysteresis, 20%, provides high performance over vari- ous air gaps and immunity to false switching on noise, vibration, backlash, or other transient events. figure 8 graphically demonstrates the establishment of the switching threshold levels.because the thresholds are established dynamically as a percentage of the peak-to-peak signal, the effect of a baseline shift is minimized. as a result, the effects of offsets induced by tilted or off-center installation are minimized. update the ats625 incorporates an algorithm that continuously moni- tors the system and updates the switching thresholds accordingly. the switchpoint for each edge is determined by the signal result- ing from the previous two edges. because variations are tracked in real time, the sensor has high immunity to target run-out and retains excellent accuracy and functionality in the presence of both run-out and transient mechanical events. figure 9 shows how the sensor uses historical data to provide the switching threshold for a given edge. switching threshold levels at constant v proc level 0 100 b op v+ v proc (%) device state b rp off on off on 60 40 figure 8. switchpoint relationship to thresholds.the device switches when v proc passes a threshold level, b op or b rp , while changing in the corresponding direction: increasing for a b op switchpoint, and decreasing for a b rp switchpoint. figure 9. switchpoint determination. the two previous v proc peaks are used to determine the next threshold level: panel a, operate point, and panel b, release point. dynamic b op threshold determination dynamic b rp threshold determination 0 100 b op v+ v proc (%) device state on off 60 0 100 v+ v proc (%) device state b rp off on 40 (a) (b)
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 15 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com sensor and target evaluation -400 -350 -300 -250 -200 -150 -100 -50 0 50 100 150 200 250 300 0 30 60 90 120 150 180 target rotation () differential flux density, b in (g) 0.75 1.00 1.50 2.00 2.50 3.00 ag (mm) magnetic map, reference target 60+2 with ats625 0 100 200 300 400 500 600 700 800 0.5 1.0 1.5 2.0 2.5 3.0 3.5 ag (mm) peak-peak differential flux density, b in (g) air gap versus magnetic field, reference target 60+2 with ats625 magnetic profile in order to establish the proper operating specification for a particular sensor and target system, a systematic evaluation of the magnetic circuit should be performed. the first step is the generation of a magnetic map of the target. by using a calibrated device, a magnetic profile of the system is made. figure 10 is a magnetic map of the 60+2 reference target. a single curve can be derived from this map data, and be used to describe the peak-to-peak magnetic field strength versus the size of the air gap, ag. this allows determination of the minimum amount of magnetic flux density that guarantees operation of the sensor, b in , so the system designer can determine the maximum allowable ag for the sensor and target system. referring to fig- ure 11, a b in of 60 g corresponds to a maximum ag of approxi- mately 2.5 mm. figure 10. magnetic data for the reference target 60+2 with ats625. in the top panel, the signature region appears in the cente r of the plot.
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 16 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com accuracy while the update algorithm will allow the sensor to adapt to typical air gap variations, major changes in air gap can adversely affect switching performance. when characterizing sensor performance over a significant air gap range, be sure to re-power the device at each test at different air gaps. this ensures that self-calibration occurs for each installation condition. see the operating characteristics table and the charts in the character- istic data: relative timing accuracy section for performance information. repeatability repeatability measurement methodology has been formulated to minimize the effect of test system jitter on device measurements. by triggering the measurement instrument, such as an oscillo- scope, close to the desired output edge, the speed variations that occur within a single revolution of the target are effectively nul- lified. because the trigger event occurs a very short time before the measured event, little opportunity is given for measurement system jitter to impact the time-based measurements. after the data is taken on the oscilloscope, statistical analysis of the distribution is made to quantify variability and capabil- ity. although complete repeatability results can be found in the characteristic data: repeatability section, figure 11 shows the correlation between magnetic signal strength and repeatability. because an direct relationship exists between magnetic signal strength and repeatability, optimum repeatability performance can be attained through minimizing the operating air gap and optimizing the target design. figure 11. repeatability measurement methodology target mechanical profile sensor output electrical profile (target movement from pin 1 to pin 4) low resolution encoder high resolution encoder oscilloscope triggers at n events after low-resolution pulse statistical distribution of 1000 sweeps next high-resolution encoder pulse (at target edge) x oscilloscope trace of 1000 sweeps for the same output edge
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 17 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com power derating thermal characteristics may require derating at maximum conditions, see application information characteristic symbol test conditions* value units package thermal resistance r ja minimum-k pcb (single layer, single-sided, with copper limited to solder pads) 126 oc/w low-k pcb (single-layer, single-sided with copper limited to solder pads and 3.57 in. 2 (23.03 cm 2 ) of copper area each side) 84 oc/w 0 5 10 15 20 25 30 20 40 60 80 100 120 140 160 180 maximum allowable v cc (v) t j(max) = 165oc power derating curve (r q ja = 126 oc/w) minimum-k pcb (r q ja = 84 oc/w) low-k pcb 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, t a (c) power dissipation, p d (m w) power dissipation versus ambient for sample pcbs (r ja = 126 oc/ w) mi n imum-k pcb ( r j a =84 oc/w) low-k pcb *additional information is available on the allegro web site.
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 18 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com the device must be operated below the maximum junction temperature of the device, t j(max) . under certain combinations of peak conditions, reliable operation may require derating sup- plied power or improving the heat dissipation properties of the application. this section presents a procedure for correlating factors affecting operating t j . (thermal data is also available on the allegro microsystems web site.) the package thermal resistance, r ja , is a figure of merit sum- marizing the ability of the application and the device to dissipate heat from the junction (die), through all paths to the ambient air. its primary component is the effective thermal conductivity, k, of the printed circuit board, including adjacent devices and traces. radiation from the die through the device case, r jc , is relatively small component of r ja . ambient air temperature, t a , and air motion are significant external factors, damped by overmolding. the effect of varying power levels (power dissipation, p d ), can be estimated. the following formulas represent the fundamental relationships used to estimate t j , at p d . p d = v in i in (1) t = p d r ja (2) t j = t a + t (3) for example, given common conditions such as: t a = 25c, v in = 12 v, i in = 4 ma, and r ja = 140 c/w, then: p d = v in i in = 12 v 4 ma = 48 mw t = p d r ja = 48 mw 140 c/w = 7c t j = t a + t = 25c + 7c = 32c a worst-case estimate, p d(max) , represents the maximum allow- able power level, without exceeding t j(max) , at a selected r ja and t a . example : reliability for v cc at t a = 150c, package sg, using minimum-k pcb. observe the worst-case ratings for the device, specifically: r ja = 126c/w, t j(max) = 165c, v cc(max) = 26.5 v, and i cc(max) = 8 ma. note that i cc(max) at t a = 150c is lower than the i cc(max) at t a = 25c given in the operating characteristics table. calculate the maximum allowable power level, p d(max) . first, invert equation 3: t max = t j(max) ? t a = 165 c ? 150 c = 15 c this provides the allowable increase to t j resulting from internal power dissipation. then, invert equation 2: p d(max) = t max r ja = 15c 126 c/w = 119 mw finally, invert equation 1 with respect to voltage: v cc(est) = p d(max) i cc(max) = 119 mw 8 ma = 14.9 v the result indicates that, at t a , the application and device can dissipate adequate amounts of heat at voltages v cc(est) . compare v cc(est) to v cc(max) . if v cc(est) v cc(max) , then reli- able operation between v cc(est) and v cc(max) requires enhanced r ja . if v cc(est) v cc(max) , then operation between v cc(est) and v cc(max) is reliable under these conditions.
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 19 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com sensor evaluation: emc characterization only test name* reference specification esd ? human body model aec-q100-002 esd ? machine model aec-q100-003 conducted transients iso 7637-1 direct rf injection iso 11452-7 bulk current injection iso 11452-4 tem cell iso 11452-3 *please contact allegro microsystems for emc performance
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 20 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com package sg, 4-pin sip preliminary dimensions, for reference only untoleranced dimensions are nominal. dimensions in millimeters u.s. customary dimensions (in.) in brackets, for reference only dimensions exclusive of mold flash, burrs, and dambar protrusions exact case and lead configuration at supplier discretion within limits shown 1.08 .043 8.0 .315 5.5 .217 0.38 .015 4.7 .185 15.3 .602 5.8 .228 2.9 .114 1.7 .067 0.4 .016 0.6 .024 1.27 .050 20.95 .825 24 3 1 a a c d b a b c dambar removal protrusion (16x) e hall elements (2x) e metallic protrusion, electrically connected to pin 4 and substrate (both sides) thermoplastic molded lead bar for alignment during shipment active area depth, 0.43 [.017] d e 1.10 .0433 1.10 .0433
true zero-speed low-jitter high accuracy gear tooth sensor ats625lsg 21 allegro microsystems, inc. 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 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 permit improvements in the per for mance, reliability, or manufactur- ability of its products. before placing an order, the user is cautioned to verify that the information being relied upon is current. allegro products are not authorized for use as critical components in life-support devices or sys tems without express written approval. 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. copyright ? 2005, 2006 allegro microsystems, inc.

▲Up To Search▲

Price & Availability of ATS625LSGTN-T3

	To Download ATS625LSGTN-T3 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .