A3423 Dual Channel Hall Effect Direction Detection Sensor IC This device is in production, however, it has been deemed Pre-End of Life. The product is approaching end of life. Within a minimum of 6 months, the device will enter its final, Last Time Buy, order phase. Date of status change: June 3, 2013 Recommended Substitutions: For existing customer transition, and for new customers or new applications, refer to the A1233. NOTE: For detailed information on purchasing options, contact your local Allegro field applications engineer or sales representative. Allegro MicroSystems, LLC reserves the right to make, from time to time, revisions to the anticipated product life cycle plan for a product to accommodate changes in production capabilities, alternative product availabilities, or market demand. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, LLC assumes no responsibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use. A3423 Dual Channel Hall Effect Direction Detection Sensor IC Features and Benefits Description ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ The A3423 is a dual-channel Hall-effect sensor IC 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 μm. Maintaining accurate displacement between the two active Hall elements eliminates the major manufacturing hurdle encountered in fine-pitch detection applications. The A3423 is a highly sensitive, temperature-stable magnetic device ideal for use in harsh automotive and industrial environments. 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 protection Packages 8-pin SOIC (suffix L) 4-pin SIP (suffix K) The Hall elements of the A3423 are spaced 1.63 mm apart, which provides excellent speed and direction information for small-geometry targets. 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 3.8 to 24 V. End-of-line 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 device and low noise. The A3423 has integrated protection against transients on the supply and output pins and short-circuit protection on all outputs. Not to scale The A3423 is available in a 4-pin SIP and a plastic 8-pin SOIC surface mount package (the SOIC version is currently in development). Both packages are lead (Pb) free, with 100% matte tin leadframe plating. Functional Block Diagram L package only VCC Regulator Output Current Limit OUTA Output Current Limit DIR Output Current Limit SPD Output Current Limit OUTB Power-on Logic Direction Logic E1 Trim E2 GND A3423-DS, Rev. 5 L package only A3423 Dual Channel Hall Effect Direction Detection Sensor IC Selection Guide Part Number Packing1 Package A3423EK-T 4-pin through hole SIP Bulk bag, 500 pieces/bag A3423ELTR-T 8-pin surface mount SOIC2 Tape and reel, 3000 pieces/reel A3423LK-T 4-pin through hole SIP Bulk bag, 500 pieces/bag A3423LLTR-T 8-pin surface mount SOIC2 1Contact Allegro for additional packing options. 2SOIC package currently in development. Tape and reel, 3000 pieces/reel TA (°C) –40 to 85 –40 to 150 Absolute Maximum Ratings Characteristic Symbol Notes Units Supply Voltage VCC 30 V Reverse Battery Voltage VRB –30 V VOUT VCC V IOUT(SINK) 30 mA Output Off Voltage Output Sink Current Magnetic Flux Density –40°C to 150°C Rating B Unlimited G Range E –40 to 85 ºC Range L Operating Ambient Temperature TA –40 to 150 ºC Storage Temperature Tstg –65 to 165 ºC TJ(max) 165 ºC Maximum Junction Temperature Pin-out Diagrams Terminal List Table Number K L VCC 1 8 GND 1 1 Name Description VCC Input power supply; tie to GND with bypass capacitor Output signal indicating direction of target movement DIR 2 7 NC 2 2 DIR OUTA 3 6 NC – 3 OUTA Analog output indicating B at E1 Hall element SPD 4 5 OUTB 3 4 SPD Output signal indicating speed of target movement – 5 OUTB – 6, 7 NC 4 8 GND L Package 4 GND DIR 3 SPD 2 VCC 1 Analog output indicating B at E2 Hall element No connection Ground connection K Package Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 2 A3423 Dual Channel Hall Effect Direction Detection Sensor IC OPERATING CHARACTERISTICS valid at TA = –40°C to 150°C, TJ ≤ TJ (max), through full operating air gap range, unless otherwise noted Characteristics Symbol Test Conditions Min. Typ. Max. Units 3.8 – 24 V – <1 10 μA – – 3.7 V Electrical Characteristics Supply Voltage Output Leakage Current VCC Operating, TJ ≤ 165°C IOFF All outputs VOUT ≤ VCC(max) Undervoltage Lockout VCC(UV) Undervoltage Hysteresis VCC(hys) Lockout (VCC(UV)) – Shutdown – 0.4 – V tr CLOAD = 20 pF, RLOAD = 1 kΩ – 200 – ns tf CLOAD = 20 pF, RLOAD = 1 kΩ Output Rise Time Output Fall Time Supply Current ICC Low Output Voltage Vsat Output Current Limit IOM Speed Output Delay* Power-on Time td tON – 300 – ns 3.4 8.2 14 mA All outputs; IOUT = 15 mA; B > BOP(A), B > BOP(B) – 210 500 mV All outputs 30 – 60 mA Delay between direction changing and speed output transition 0.5 2.5 5 μs B > BOP + 5 G – 2 5 μs – V Transient Protection Characteristics Supply Zener Voltage VZ(sup) ICC = 17 mA, TA = 25°C 30 – Output Zener Voltage VZ(out) IOUT = 3 mA, TA = 25°C 30 – – V Supply Zener Current IZ(sup) Vsupply = 30 V, TA = 25°C – – 17 mA Output Zener Current IZ(out) VOUT = 30 V, TA = 25°C – – 3 mA Reverse Battery Current IRCC VRCC = –28 V, TA = 25°C – – 15 mA Operate Point (Channel A and Channel B) BOP B(A) > BOP(A), B(B) > BOP(B) –35 15 55 G Release Point (Channel A and Channel B) BRP B(A) < BOP(A), B(B) < BOP(B) –55 –15 35 G Bhys Magnetic Characteristics Hysteresis (Channel A and Channel B) BOP – BRP 10 30 60 G Operate Symmetry SYMOP(AB) BOP(A) – BOP(B) –50 – 50 G Release Symmetry SYMRP(AB) BRP(A) – BRP(B) –50 – 50 G * Valid only after the first speed (SPD pin) signal transition. First speed signal transition has no delay. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 3 A3423 Dual Channel Hall Effect Direction Detection Sensor IC THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information Characteristic Symbol RθJA Package Thermal Resistance Test Conditions* Value Units Package K, 1-layer PCB with copper limited to solder pads 177 ºC/W Package L, 1-layer PCB with copper limited to solder pads 140 ºC/W Package L, 4-layer PCB 80 ºC/W *Additional thermal information available on Allegro website. Maximum Allowable VCC (V) Power Derating Curve 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 VCC(max) Package K (RQJA = 177 ºC/W) 1-layer PCB, Package L (RQJA = 140 ºC/W) 4-layer PCB, Package L (RQJA = 80 ºC/W) VCC(min) 20 40 60 80 100 120 140 160 180 Temperature (ºC) Power Dissipation, PD (mW) Power Dissipation versus Ambient Temperature 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 800 700 600 500 400 300 200 100 0 4 (R -lay QJ A er = PC 80 B ºC , Pa /W ck ) ag 1-l (R ayer PC QJ A = 14 B, P 0 º ac C/ kag W) eL Pac (R kage K QJA = 177 20 40 60 ºC/ e L W) 80 100 120 Temperature (°C) 140 160 180 Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 4 A3423 Dual Channel Hall Effect Direction Detection Sensor IC Performance Characteristics Supply Current at TA = 25°C Supply Current versus Ambient Temperature 13 10 3 outputs on, Vcc=8V 3 outputs off, Vcc=8V 3 outputs on, Vcc=12V 8 3 outputs off, Vcc=12V 7 Supply Current (mA) Supply Current (mA) 12 9 6 11 3 outputs on 3 outputs off 10 9 8 7 6 5 5 -50 -25 0 25 50 75 100 125 150 2 4 6 8 TA (°C) 14 16 18 20 22 24 Magnetic Operate Point versus Ambient Temperature 400 55 350 45 300 35 25 250 200 Iout = 20mA Iout = 15mA 150 BOP (G) Vsat (mV) 12 VCC (V) Saturation Voltage versus Ambient Temperature 100 Vcc = 3.8V Vcc = 8V Vcc = 12V Vcc = 18V Vcc = 24V 15 5 -5 -15 50 -25 0 -35 -50 0 50 100 150 -50 0 TA (°C) 50 100 150 TA (°C) Magnetic Release Point versus Ambient Temperature Hysteresis versus Ambient Temperature 35 60 25 55 50 15 Vcc = 3.8V Vcc = 8V Vcc = 12V Vcc = 18V Vcc = 24V -5 -15 -25 -35 45 Hysteresis (G) 5 BRP (G) 10 Vcc = 3.8V Vcc = 8V Vcc = 12V Vcc = 18V Vcc = 24V 40 35 30 25 20 -45 15 -55 10 -50 0 50 TA (°C) 100 150 -50 0 50 100 150 TA (°C) Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 5 A3423 Dual Channel Hall Effect Direction Detection Sensor IC Functional Description The integrated circuit contains an internal voltage regulator that powers the Hall elements and both the analog and digital circuitry. This regulator allows operation over a wide supply voltage range and provides some immunity to supply noise. The device also contains logic circuitry that decodes the direction of rotation of the ring magnet. The response of the device to the magnetic field produced by a rotating ring magnet is shown in the Performance Characteristics section. Note the phase shift between the two integrated Hall elements. Quadrature/Direction Detection Internal logic circuitry provides outputs representing the speed and direction of the magnetic field across the face of the package. For the direction signal to be appropriately updated, a quadrature relationship must be maintained between the target magnetic pole width, the pitch between the two Hall elements (E1 and E2) in the device, and, to a lesser extent, the magnetic switchpoints. direction (DIR pin), E1 element output (OUTA pin), E2 element output (OUTB pin), and target speed (SPD pin). For optimal design, the device should be actuated by a ring magnet that presents to the front of the device a field with a pole width two times the Hall element-to-element spacing. This will produce a sinusoidal magnetic field whose period (denoted as Τ) is then four times the element-to-element spacing. A quadrature relationship can also be maintained for a ring magnet with fields having a period that satisfies the relationship: nΤ/4 = 1.63 mm , where n is any odd integer. Therefore, ring magnets with polepair spacing equal to 6.52 mm (n = 1), 2.17 mm (n = 3), 1.3 mm (n = 5), and so forth, are permitted. Outputs The device provides up to four saturated outputs: target DIR provides the direction output of the device and is defined as off (high) for targets moving in the direction from E1 to E2 and on (low) for the direction E2 to E1. SPD provides an XORed output of the two Hall elements (see figure 1). Because of internal delays, DIR is always updated before SPD and is updated at every transition of OUTA and OUTB (internal) allowing the use of up-down counters without the loss of pulses. Power-on State At power on, the logic circuitry is reset to pro- vide an off (high) state for all the outputs. If any of the channels is subjected to a field greater than BOP, the internal logic will set accordingly, and the outputs will switch to the expected state. Power-on Time This characteristic, tON, is the elapsed time from when the supply voltage reaches the device supply minimum until the device output becomes valid (see figure 2). Target changes direction of rotation +B 0 –B +B 0 –B OUTA OUTB SPD (OUTA XOR OUTB) DIR td Figure 1 Figure 2 Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 6 A3423 Dual Channel Hall Effect Direction Detection Sensor IC Application Information Operation with Fine-Pitch Ring Magnets. For targets with a cir- cular pitch of less than 4 mm, a performance improvement can be observed by rotating the front face of the device (see below). This rotation decreases the effective Hall element-to-element spacing, provided that the Hall elements are not rotated beyond the width of the target. Applications. It is strongly recommended that an external 0.01 μF bypass capacitor be connected (in close proximity to the device) between the supply and ground of the device to Normal Coplanar Alignment reduce both external noise and noise generated by the internal logic. The simplest form of magnet that will operate these devices is a ring magnet. Other methods of operation, such as linear magnets, are possible. Extensive applications information on magnets and Hall-effect sensor ICs is also available in the “Hall-Effect IC Applications Guide” which can be found in the latest issue of Application Note 27701, at www.allegromicro.com/techpub2/an/ an27701.pdf. Rotated Alignment D cos A D Target Profile of Rotation S N S E1 E1 E2 E2 A Target Circular Pitch, P Target Face Width, F F < D sin A Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 7 A3423 Dual Channel Hall Effect Direction Detection Sensor IC Package K, 4-Pin SIP +0.08 5.21 –0.05 45° B E 1.63 E 1.55 ±0.05 1.79 D NNNN 1.32 E +0.08 3.43 –0.05 E1 E2 2.16 MAX Mold Ejector Pin Indent Branded Face 2 3 D Standard Branding Reference View 0.84 REF N = Device part number Y = Last two digits of year of manufacture W = Week of manufacture For Reference Only; not for tooling use (reference DWG-9010) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown 4 14.73 ±0.51 +0.06 0.38 –0.03 +0.07 0.41 –0.05 1 45° A 1 YYWW A Dambar removal protrusion (8X) B Gate and tie bar burr area C Branding scale and appearance at supplier discretion D Active Area Depth, .0.42 mm E Hall elements (E1 and E2); not to scale 1.27 NOM Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 8 A3423 Dual Channel Hall Effect Direction Detection Sensor IC Package L, 8-Pin SOIC 4.90 ±0.10 1.63 E 1.63 E 8 D 8° 0° 0.65 1.27 8 1.75 0.25 0.17 1.95 E E1 3.90 ±0.10 A 1 6.00 ±0.20 5.60 1.04 REF E2 2 0.25 BSC SEATING PLANE 0.10 C 1.27 BSC C 2 PCB Layout Reference View SEATING PLANE GAUGE PLANE Branded Face 8X 0.51 0.31 1 1.27 0.40 E 1.09 C NNNNNNN YYWW LLLLL 1.75 MAX 0.25 0.10 For Reference Only; not for tooling use (reference MS-012AA) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown A Terminal #1 mark area B Branding scale and appearance at supplier discretion C Reference land pattern layout (reference IPC7351 SOIC127P600X175-8M); all pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary to meet application process requirements and PCB layout tolerances D Active Area Depth 0.40 NOM E Hall elements (E1 and E2); not to scale 1 B Standard Branding Reference View N = Device part number = Supplier emblem Y = Last two digits of year of manufacture W = Week of manufacture L = Lot number Copyright ©2007-2013, Allegro MicroSystems, LLC Allegro MicroSystems, LLC reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the performance, 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 information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, LLC assumes no responsibility for its use; nor for any infringement of patents or other rights of third parties which may result from its use. For the latest version of this document, visit our website: www.allegromicro.com Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 9