A3423 A3423-DS A3423EK-T A3423ELTR-T A3423LK-T A3423LLTR-T MS-012 SOIC127P600-8M - Datasheet Archive

 

Dual Channel Hall Effect Direction Detection Sensor Features and Benefits Description The A3423 is a dual-channel Hall-effect

 

A3423 A3423 Dual Channel Hall Effect Direction Detection Sensor Features and Benefits Description The A3423 A3423 is a dual-channel Hall-effect sensor ideal for use in speed and direction sensing applications incorporating encoder ring-magnet targets. The A3423 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 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 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 sensor and low noise. The A3423 A3423 has integrated protection against transients on the supply and output pins and short-circuit protection on all outputs. Not to scale The A3423 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 Output Current Limit Output Current Limit DIR SPD Output Current Limit Regulator OUTA Output Current Limit VCC OUTB Power-on Logic Direction Logic E1 Trim E2 GND A3423-DS A3423-DS, Rev. 1 L package only A3423 A3423 Dual Channel Hall Effect Direction Detection Sensor Selection Guide Part Number Packing1 Package A3423EK-T A3423EK-T 4-pin through hole SIP Bulk bag, 500 pieces/bag A3423ELTR-T A3423ELTR-T 8-pin surface mount SOIC2 Tape and reel, 3000 pieces/reel A3423LK-T A3423LK-T 4-pin through hole SIP Bulk bag, 500 pieces/bag A3423LLTR-T 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 Name Description L VCC 1 8 GND 1 1 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, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 2 A3423 A3423 Dual Channel Hall Effect Direction Detection Sensor 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 ­ 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 s B > BOP + 5 G ­ 2 5 ms ­ V ICC Speed Output Delay* Power-on Time td tON 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, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 3 A3423 A3423 Dual Channel Hall Effect Direction Detection Sensor THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information Characteristic Symbol Test Conditions* Value Units Package K, 1-layer PCB with copper limited to solder pads ºC/W Package L, 1-layer PCB with copper limited to solder pads 140 ºC/W Package L, 4-layer PCB RJA Package Thermal Resistance 177 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 (R JA = 177 ºC/W) 1-layer PCB, Package L (R JA = 140 ºC/W) 4-layer PCB, Package L (R JA = 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 JA er = PC 80 B ºC , Pa /W ck ) ag 1-l (R ayer JA = P C 14 B, P 0 º ac C/ kag W) eL Pac (R kage K JA = 177 20 40 60 ºC/ e L W) 80 100 120 Temperature (°C) 140 160 180 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 4 A3423 A3423 Dual Channel Hall Effect Direction Detection Sensor 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) Saturation Voltage versus Ambient Temperature 14 16 18 20 22 24 Magnetic Operate Point versus Ambient Temperature 55 350 45 300 35 25 250 200 Iout = 20mA Iout = 15mA 150 BOP (G) Vsat (mV) 12 VCC (V) 400 100 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, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 5 A3423 A3423 Dual Channel Hall Effect Direction Detection Sensor Functional Description The integrated circuit contains an internal voltage regulator that powers the Hall sensors 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 sensor, and, to a lesser extent, the magnetic switchpoints. direction (DIR pin), E1 sensor output (OUTA pin), E2 sensor output (OUTB pin), and target speed (SPD pin). For optimal design, the sensor should be actuated by a ring magnet that presents to the front of the sensor 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 ) 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: n/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 sensor 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, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 6 A3423 A3423 Dual Channel Hall Effect Direction Detection Sensor Application Information Operation with Fine-Pitch Ring Magnets. For targets with a circular pitch of less than 4 mm, a performance improvement can be observed by rotating the front face of the sensor subassembly (see below). This sensor 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 F bypass capacitor be connected (in close proximity to the Hall sensor) 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 sensors 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 D Target Profile of Rotation S N S E1 E1 Target Circular Pitch, P E2 E2 Target Face Width, F F < D sin Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 7 A3423 A3423 Dual Channel Hall Effect Direction Detection Sensor Package K, 4-Pin SIP .205 [5.21] 45° B .0704 1.79 A B .0642 1.63 .061 [1.55] .0520 [1.32] B .135 [3.43] E1 E2 .033 [0.84] .085 [2.16] MAX 1 .580 [14.73] 45° 2 3 4 .016 [0.41] .017 [0.43] All dimensions nominal, not for tooling use Dimensions in inches, metric dimensions (mm) in brackets, for reference only .050 [1.27] A Active Area Depth, .0165 [0.42] metric dimensions controlling B Hall elements (E1 and E2); not to scale Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 8 A3423 A3423 Dual Channel Hall Effect Direction Detection Sensor Package L, 8-Pin SOIC 4.90 1.63 .0643 D 1.63 .0642 4º D 8 C 1.90 0.21 1.95 .0769 D 3.90 4.70 A E1 1 0.65 E2 0.84 D 2 D 1.09 .0429 1.27 0.25 8X B 6.00 PCB Layout Reference View SEATING PLANE 0.10 C C SEATING PLANE GAUGE PLANE 1.75 MAX 0.41 1.27 0.18 All dimensions nominal, not for tooling use (reference JEDEC MS-012 MS-012 AA) Dimensions in millimeters A Terminal #1 mark area B Reference pad layout (reference IPC SOIC127P600-8M SOIC127P600-8M) All pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary to meet application process requirements and PCB layout tolerances C Active Area Depth 0.40 mm D Hall elements, E1 and E2 (not to scale); U.S. Customary dimensions (inches) controlling; shown in brackets 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 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, Inc. 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, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 9