Dual Channel Hall Effect Direction Detection Sensor
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
Description
The 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 environments. 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 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 has integrated protection against transients on the supply and output pins and short-circuit protection on all outputs. The A3423 is available 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.
L package only Output Current Limit Regulator Power-on Logic OUTA VCC
Part Number A3423ELTR-T A3423LK-T Package 4-pin through hole SIP 8-pin surface mount SOIC2 4-pin through hole SIP Packing1 Bulk bag, 500 pieces/bag Tape and reel, 3000 pieces/reel Bulk bag, 500 pieces/bag Tape and reel, 3000 pieces/reel TA (°C) to 150
A3423LLTR-T 8-pin surface mount SOIC2 1Contact Allegro for additional packing options. 2SOIC package currently in development.
Characteristic Supply Voltage Reverse Battery Voltage Output Off Voltage Output Sink Current Magnetic Flux Density Operating Ambient Temperature Storage Temperature Maximum Junction Temperature Symbol VCC VRB VOUT IOUT(SINK) B TA Tstg TJ(max) Range E Range to 150°C Notes Rating 30 30 VCC 30 Unlimited to 165 Units G ºC
Number K L VCC DIR OUTA SPD OUTB NC GND Input power supply; tie to GND with bypass capacitor Output signal indicating direction of target movement Analog output indicating at E1 Hall element Output signal indicating speed of target movement Analog output indicating at E2 Hall element No connection Ground connection
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts (508) 853-5000 www.allegromicro.com
OPERATING CHARACTERISTICS valid 150°C, TJ (max), through full operating air gap range, unless otherwise noted Characteristics Electrical Characteristics Supply Voltage Output Leakage Current Undervoltage Lockout Undervoltage Hysteresis Output Rise Time Output Fall Time Supply Current Low Output Voltage Output Current Limit Speed Output Delay* Power-on Time Transient Protection Characteristics Supply Zener Voltage Output Zener Voltage Supply Zener Current Output Zener Current Reverse Battery Current Magnetic Characteristics Operate Point (Channel A and Channel B) Release Point (Channel A and Channel B) Hysteresis (Channel A and Channel B) Operate Symmetry Release Symmetry BOP BRP Bhys SYMOP(AB) SYMRP(AB) B(A) > BOP(A), B(B) > BOP(B) B(A) < BOP(A), B(B) < BOP(B) BOP BRP BOP(A) BOP(B) BRP(A) BRP(B) VZ(sup) VZ(out) IZ(sup) IZ(out) IRCC ICC = 17 mA, = 25°C IOUT = 3 mA, = 25°C Vsupply = 25°C VOUT = 25°C VRCC V mA VCC IOFF VCC(UV) VCC(hys) tr tf ICC Vsat IOM td tON All outputs; IOUT = 15 mA; B > BOP(A), B > BOP(B) All outputs Delay between direction changing and speed output transition B > BOP 5 G Lockout (VCC(UV)) Shutdown CLOAD = 20 pF, RLOAD 1 k CLOAD = 20 pF, RLOAD 1 k Operating, TJ 165°C All outputs VOUT VCC(max) mA ms Symbol Test Conditions Min. Typ. Max. Units
* 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 (508) 853-5000 www.allegromicro.com
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