The A3421xKA and A3422xKA Hall-effect, direction-detection sensors are a new generation of special-function integrated sensors that are capable of sensing the direction of rotation of a ring magnet. These transducers provide separate digital outputs that provide information on magnet rotation speed, direction, and magnet pole count. These devices eliminate the major manufacturing hurdles encountered in fine-pitch direction-detection applications, namely maintaining accurate mechanical location between the two active Hall elements. Here, the two Hall elements are photolithographically aligned to better than 1 µm, as contrasted with µm or worse mechanical location tolerance when manufactured discretely. These highly sensitive, temperature-stable, magnetic transducers are ideal for use in digital-encoder systems in the harsh environments of automotive or industrial applications. The is a high-hysteresis device designed for low-resolution pulse counting while the is a high-sensitivity device optimized for use with high-density magnets.
Pinning is shown viewed from branded side.
Supply Voltage, VCC. 18 V Magnetic Flux Density, B. Unlimited Output OFF Voltage, VOUT.
Package Power Dissipation, PD. 500 mW Operating Temperature Range, TA Suffix `EKA'. to +85°C Suffix `LKA'. to +150°C Storage Temperature Range, TS. to +170°C
The A3421xKA and A3422xKA monolithic integrated circuits contain two independent Hall-effect latches whose digital outputs are internally coupled to CMOS logic circuitry that decodes signal speed and direction. Extremely low-drift BiCMOS circuitry is used for the amplifiers to ensure symmetry between the two latches so that signal quadrature can be maintained. An on-chip voltage regulator allows the use of these devices from 18 V supply. Both devices have standard open-collector outputs; the logic operation of both devices is the same.
Two operating temperature ranges are provided; suffix `E' is for the automotive and industrial temperature range to +85°C, suffix `L' is for the automotive and military temperature range to +150°C. The 5-pin `KA' SIP package provides a costcompetitive solution to linear magnetic sensing in harsh environments.
Internal Direction-Decoding Circuitry Two Matched Hall Latches On A Single Substrate Superior Temperature Stability 18 V Operation Electrically Defined Power-On State Under-Voltage Lockout
Always order by complete part number, e.g., A3421EKA.
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts (508) 853-5000 Copyright © 1999 Allegro MicroSystems, Inc.
ELECTRICAL CHARACTERISTICS over operating temperature range.
Limits Characteristic Supply Voltage Range Output Leakage Current Output Saturation Voltage Power-On State Under-Voltage Lockout Under-Voltage Hysteresis Power-On Time Output Rise Time Output Fall Time Direction Change Delay Supply Current Symbol VCC IOFF VOUT(SAT) POS VCC(UV) VCC(hys) tpo tf td ICC Test Conditions Operating, < 165°C1 VOUT = VCC 18 V IOUT 20 mA VCC < BOP2 IOUT = 20 mA, VCC Lockout (VCC(UV)) - Shutdown VCC = 20 pF, = 20 pF, = 20 pF, = 820 VCC 8 V, All outputs OFF Min. 4.5 OFF 0.5 5.0 Typ. <1.0 0.21 OFF Max. 10 0.50 OFF 5.0 18 Units µs mA
NOTES:1. Maximum supply voltage must be adjusted for power dissipation and ambient temperature. 2. Typical Data is at VCC 12 V and = +25°C and is for design information only.