Dual Channel Hall Effect Direction Detection Sensor

1 DescriptionThe A3423 is a dual - Channel hall - Effect Sensor ideal for use in speed and Direction sensing applications incorporating encoder ring-magnet targets. The A3423 provides various output signals that indicate speed and Direction of target rotation. The hall elements are both photolithographically aligned to better than 1 m. Maintaining accurate displacement between the two active hall elements eliminates the major manufacturing hurdle encountered in fine-pitch Detection applications. The sensors are highly sensitive, temperature-stable magnetic sensors ideal for use in harsh automotive and industrial hall elements of the A3423 are spaced mm apart, which provides excellent speed and Direction information for small-geometry targets.

2 Extremely low-drift amplifiers guarantee symmetry between the switches to maintain signal quadrature. An on-chip regulator allows the use of this device over a wide operating voltage range of to 24 trimming of the hall element switchpoints provides tight matching capability. The continuous-time nature of the hall elements delivers a fast start-up of the Sensor and low A3423 has integrated protection against transients on the supply and output pins and short-circuit protection on all A3423 is available in a 4-pin SIP and a plastic 8-pin SOIC surface mount package (the SOIC version is currently in development).

3 Both packages are lead (Pb) free, with 100% matte tin leadframe , Rev. 3 Features and Benefits Precisely aligned dual hall elements Tightly matched magnetic switchpoints Speed and Direction outputs Individual hall element outputs (L package) Fast power-on time Output short circuit protection Operation from an unregulated power supply Wide operating temperature range Wide operating voltage range Integrated EMC-ESD protectionFunctional Block DiagramNot to scaleA3423 Packages8-pin SOIC (suffix L) 4-pin SIP (suffix K)

4 dual Channel hall Effect Direction Detection SensorTrimOutput Current LimitOutput Current LimitOutput Current LimitDirectionLogicOutput Current LimitRegulatorPower-onLogicE1 GNDVCCE2L package onlyL package onlyOUTAOUTBSPDDIRDual Channel hall Effect Direction Detection SensorA34232 Allegro MicroSystems, Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) GuidePart NumberPackagePacking1TA( C)A3423EK-T4-pin through hole SIPBulk bag, 500 pieces/bag 40 to 85A3423 ELTR-T8-pin surface mount SOIC2 Tape and reel, 3000 pieces/reelA3423LK-T4-pin through hole SIPBulk bag, 500 pieces/bag 40 to 150A3423 LLTR-T8-pin surface mount SOIC2 Tape and reel.

5 3000 pieces/reel1 Contact Allegro for additional packing package currently in Maximum RatingsCharacteristicSymbolNotesRatingUn itsSupply Voltage VCC 40 C to 150 C30 VReverse Battery VoltageVRB 30 VOutput Off VoltageVOUTVCCVO utput Sink CurrentIOUT(SINK)30mAMagnetic Flux DensityBUnlimitedGOperating Ambient TemperatureTARange E 40 to 85 CRange L 40 to 150 CStorage TemperatureTstg 65 to 165 CMaximum Junction TemperatureTJ(max)165 CTerminal List TableNumberNameDescriptionKL11 VCCI nput power supply; tie to GND with bypass capacitor22 DIRO utput signal indicating Direction of target movement 3 OUTAA nalog output indicating B at E1 hall element34 SPDO utput signal indicating speed of target movement 5 OUTBA nalog output indicating B at E2 hall element 6, 7 NCNo connection48 GNDG round connectionPin-out DiagramsL PackageK Package87651234 GNDNCNCOUTBVCCDIROUTASPD2341 VCCDIRSPDGNDDual Channel hall Effect Direction Detection SensorA34233 Allegro MicroSystems, Northeast Cutoff, Box 15036 Worcester.

6 Massachusetts 01615-0036 (508) CHARACTERISTICS valid at TA = 40 C to 150 C, TJ TJ (max), through full operating air gap range, unless otherwise notedCharacteristicsSymbolTest CharacteristicsSupply VoltageVCCO perating, TJ 165 24 VOutput Leakage CurrentIOFFAll outputs VOUT VCC(max) <110 AUndervoltage LockoutVCC(UV) HysteresisVCC(hys)Lockout (VCC(UV)) Shutdown VOutput Rise TimetrCLOAD = 20 pF, RLOAD = 1 k 200 nsOutput Fall TimetfCLOAD = 20 pF, RLOAD = 1 k 300 nsSupply Output VoltageVsatAll outputs; IOUT = 15 mA.

7 B > BOP(A), B > BOP(B) 210500mVOutput Current LimitIOMAll outputs30 60mASpeed Output Delay*tdDelay between Direction changing and speed output transition sPower-on TimetONB > BOP + 5 G 25 sTransient Protection CharacteristicsSupply Zener VoltageVZ(sup)ICC = 17 mA, TA = 25 C30 VOutput Zener VoltageVZ(out)IOUT = 3 mA, TA = 25 C30 VSupply Zener CurrentIZ(sup)Vsupply = 30 V, TA = 25 C 17mAOutput Zener CurrentIZ(out)VOUT = 30 V, TA = 25 C 3mAReverse Battery CurrentIRCCVRCC = 28 V, TA = 25 C 15mAMagnetic CharacteristicsOperate Point ( Channel A and Channel B)BOPB(A) > BOP(A), B(B) > BOP(B) 351555 GRelease Point ( Channel A and Channel B)BRPB(A) < BOP(A), B(B) < BOP(B) 55 1535 GHysteresis ( Channel A and Channel B)BhysBOP BRP103060 GOperate SymmetrySYMOP(AB)BOP(A) BOP(B) 50 50 GRelease SymmetrySYMRP(AB)BRP(A) BRP(B) 50 50G* Valid only after the first speed (SPD pin) signal transition.

8 First speed signal transition has no Channel hall Effect Direction Detection SensorA34234 Allegro MicroSystems, Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) CHARACTERISTICS may require derating at maximum conditions, see application informationCharacteristicSymbolTest Conditions*Value UnitsPackage Thermal ResistanceR JAPackage K, 1-layer PCB with copper limited to solder pads177 C/WPackage L, 1-layer PCB with copper limited to solder pads140 C/WPackage L, 4-layer PCB80 C/W*Additional thermal information available on Allegro website.

9 6789234510111213141516171819202122232425 20406080100120140160180 Temperature ( C)Maximum Allowable VCC (V)Power Derating Curve(RQJA= 80 C/W)4-layer PCB, Package L(RQJA= 177 C/W)Package K(RQJA= 140 C/W)1-layer PCB, Package LVCC(min)VCC(max)01002003004005006007008 0090010001100120013001400150016001700180 0190020406080100120140160180 Temperature ( C)Power Dissipation, PD (mW)Power Dissipation versus Ambient Temperature(RQJA= 140 C/W)1-layer PCB, Package L(RQJA= 177 C/W)Package K(RQJA= 80 C/W)4-layer PCB, Package LDual Channel hall Effect Direction Detection SensorA34235 Allegro MicroSystems, Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) CharacteristicsSupply Current versus Ambient Temperature 5678910-50-250255075100125150TA( C)Supply Current (mA)3 outputs on, Vcc=8V3 outputs off, Vcc=8V3 outputs on, Vcc=12V3 outputs off, Vcc=12 VSupply Current at TA=25 C567891011121324681012141618202224 VCC(V)Supply Current (mA)

10 3 outputs on3 outputs offSaturation Voltage versus Ambient Temperature050100150200250300350400-5005 0100150TA( C)Vsat(mV)Iout = 20mAIout = 15mAMagnetic Operate Point versus Ambient Temperature-35-25-15-551525354555-500501 00150TA( C)BOP(G)Vcc = = 8 VVcc = 12 VVcc = 18 VVcc = 24 VMagnetic Release Point versus Ambient Temperature -55-45-35-25-15-55152535-50050100150TA( C)BRP(G)Vcc = = 8 VVcc = 12 VVcc = 18 VVcc = 24 VHysteresis versus Ambient Temperature 1015202530354045505560-50050100150TA( C)Hysteresis (G)Vcc = = 8 VVcc = 12 VVcc = 18 VVcc = 24 VDual Channel hall Effect Direction Detection SensorA34236 Allegro MicroSystems, Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) integrated circuit contains an internal voltage regulator that powers the hall sensors and both the analog and digital circuitry.