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3422
HALL-EFFECT, DIRECTION-DETECTION SENSORS
The A3422xKA Hall-effect, direction-detection sensor is a new generation of special-function integrated sensors that is capable of sensing the direction of rotation of a ring magnet. This transducer provides separate digital outputs that provide information on magnet rotation speed, direction, and magnet pole count. This device eliminates 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 m, as contrasted with 100 m or worse mechanical location tolerance when manufactured discretely. This highly sensitive, temperature-stable, magnetic transducer is ideal for use in digital-encoder systems in the harsh environments of automotive or industrial applications. The A3422xKA is a high-sensitivity device optimized for use with high-density magnets. The A3422xKA monolithic integrated circuit contains two independent Hall-effect bipolar switches 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 switches so that signal quadrature can be maintained. An on-chip voltage regulator allows the use of this device from a 4.5 V to 18 V supply. The outputs are standard open-collector outputs. Two operating temperature ranges are provided; suffix `E-' is for the automotive and industrial temperature range of -40C to +85C, suffix `L-' is for the automotive and military temperature range of -40C to +150C. The 5-pin `KA' SIP package provides a cost-competitive solution to magnetic sensing in harsh environments.
Data Sheet 27650.1B
E1
E2
X
X
LOGIC
VCC
1
2
3
4
5
DIRECTION
GROUND
E1 OUTPUT
SUPPLY
Dwg PH-015
Pinning is shown viewed from branded side.
SPEED
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VCC . . . . . . . . . . . . . . 18 V Magnetic Flux Density, B . . . . Unlimited Output OFF Voltage, VOUT . . . . . . . . . VCC Output Sink Current, IOUT . . . . . . . 30 mA Package Power Dissipation, PD . . . . . . . . . . . . . . . . . . . . . 500 mW Operating Temperature Range, TA Suffix `E-' . . . . . . . . . -40C to +85C Suffix `L-' . . . . . . . . -40C to +150C Storage Temperature Range, TS . . . . . . . . . . . . . . -65C to +170C
FEATURES
* * * *
Internal Direction-Decoding Circuitry Two Matched Hall Bipolar Switches on a Single Substrate Superior Temperature Stability 4.5 V to 18 V Operation Electrically Defined Power-On State Undervoltage Lockout
3422 HALL-EFFECT, DIRECTION-DETECTION SENSOR
Selection Guide
Part Number A3422EKA-T A3422LKA-T
1Pb-based
Pb-Free1 Yes Yes
Packing2 Bulk, 500 pieces/bag Bulk, 500 pieces/bag
Mounting 5-pin SIP through hole 5-pin SIP through hole
Ambient, TA (C) -40 to 85 -40 to 150
variants are being phased out of the product line. The variants cited in this footnote are in production but have been determined to be NOT FOR NEW DESIGN. This classification indicates that sale of this device is currently restricted to existing customer applications. The variants should not be purchased for new design applications because obsolescence in the near future is probable. Samples are no longer available. Status change: May 1, 2006. These variants include: A3422EKA and A3422LKA. 2Contact Allegro for additional packing options.
FUNCTIONAL BLOCK DIAGRAM
1 SUPPLY 2 DIRECTION
UVLO
REG
LOGIC
POWER-ON LOGIC
3
GROUND
4
E1 OUTPUT
E2
X
E1
X
5
SPEED
Dwg. FH-018
TIMING DIAGRAM
CHANGE IN DIRECTION
td DIRECTION
Dwg. WH-012A
+B 0
BOP1 BRP1
-B +B 0 BRP2 -B BOP2
OUTE1
OUTE2 (INTERNAL)
SPEED (OUTE1 XOR OUT E2)
2
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright (c) 2001, 2003 Allegro MicroSystems, Inc.
3422 HALL-EFFECT, DIRECTION-DETECTION SENSOR
ELECTRICAL CHARACTERISTICS over operating temperature range.
Limits Characteristic Supply Voltage Range Output Leakage Current Output Saturation Voltage Power-On State Undervoltage Lockout Undervoltage 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 tr tf td ICC Test Conditions Operating, TJ < 165C1 VOUT = VCC = 18 V IOUT = 20 mA VCC = 0 5 V, BRP1 < B < BOP1, BRP2 < B < BOP2 IOUT = 20 mA, VCC = 0 5 V Lockout (VCC(UV)) - Shutdown VCC > 4.5 V CL = 20 pF, RL = 820 CL = 20 pF, RL = 820 CL = 20 pF, RL = 820 VCC = 8 V, All outputs OFF Min. 4.5 -- -- OFF -- -- -- -- -- 0.5 5.0 Typ. -- <1.0 0.21 OFF 3.5 0.5 -- 200 200 1.0 9.0 Max. 18 10 0.50 OFF -- -- 50 -- -- 5.0 18 Units V A V -- V V s ns ns s mA
NOTES:1. Maximum supply voltage must be adjusted for power dissipation and ambient temperature. 2. Typical Data is at VCC = 12 V and TA = +25C and is for design information only.
ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS
0.6
0.5
0.4
0.3
RJA = 164C/W
0.2
0.1
0 25 50 75 100 125 TEMPERATURE IN C 150 175
Dwg. GH-069
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3
3422 HALL-EFFECT, DIRECTION-DETECTION SENSOR
MAGNETIC CHARACTERISTICS over operating voltage range.
Limits Characteristic Operate Point Symbol BOP Test Conditions TA = -40C TA = +25C TA = Maximum Release Point3 BRP TA = -40C TA = +25C TA = Maximum Hysteresis Bhys TA = -40C TA = +25C TA = Maximum Operate Differential Release Differential -- -- BOP1 - BOP2 BRP1 - BRP2 Min. -- -- -- -85 -75 -75 10 10 10 -- -- Typ. -- 29 -- -- -17 -- -- 46 -- -- -- Max. 85 75 75 -- -- -- -- -- -- 60 60 Units G G G G G G G G G G G
NOTES:1. Magnetic flux density is measured at most sensitive area of device, nominally located 0.0165" (0.42 mm) below the branded face of the package. 2. Typical Data is at VCC = 12 V and TA = +25C and is for design information only. 3. As used here, negative flux densities are defined as less than zero (algebraic convention).
Typical Magnetic Characteristics
50 40 30 OPERATE POINT
100
80
V =8V CC
SWITCH POINTS IN GAUSS
HYSTERESIS IN GAUSS
20 10 0 -10 RELEASE POINT -20 -30 -40 -50 -50 -25 0 25 50 75 100 125 150 V =8V CC
60
40
20
0 -50 -25 0 25 50 75 100 125 150
AMBIENT TEMPERATURE IN C
AMBIENT TEMPERATURE IN C
Dwg. GH-026-1
Dwg. GH-051-1
4
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
3422 HALL-EFFECT, DIRECTION-DETECTION SENSOR
Typical Electrical Characteristics
300
10
250
I OUT = 20 mA
V =8V CC 9.0
SATURATION VOLTAGE IN mV
200
SUPPLY CURRENT IN mA
ALL OUTPUTS ON
150
8.0
100
ALL OUTPUTS OFF 7.0
50
0 -50 -25 0 25 50 75 100 125 150
6.0 -50 -25 0 25 50 75 100 125 150
AMBIENT TEMPERATURE IN C
Dwg. GH-029-2
AMBIENT TEMPERATURE IN C
Dwg. GH-053-1
13
12
T = 25C A
11
SUPPLY CURRENT IN mA
10 ALL OUTPUTS ON 9.0
8.0 ALL OUTPUTS OFF 7.0
6.0
5.0 2.0 6.0 10 14 18
SUPPLY VOLTAGE IN VOLTS
Dwg. GH-058-3
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5
3422 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 CMOS logic circuitry that decodes the direction of rotation of the ring magnet. Quadrature/Direction Detection. Internal logic circuitry provides outputs representing 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 ring magnet pole width*, the sensor-tosensor spacing, and, to a lesser extent, the magnetic switch points. For optimal design, the sensor should be actuated with a ring magnet pole width* two times the sensor-to-sensor spacing. This will produce a sinusoidal magnetic field whose period (denoted as ) is then four times the sensor-to-sensor spacing. A quadrature relationship can also be maintained for a ring magnet that has a period that satisfies the relationship n/4 = 1.5 mm, where n is any odd integer. Therefore, ring magnets with pole-pair spacing equal to 6 mm (n = 1), 2 mm (n = 3), 1.2 mm (n = 5), etc. are permitted. The response of the device to the magnetic field produced by a rotating ring magnet is shown on page 2. Note the phase shift between the two integrated sensors. Outputs. The device provides three saturated outputs: DIRECTION, E1 OUTPUT, and SPEED. DIRECTION provides the direction output of the sensor and is defined as OFF (high) for the direction E1 to E2 and ON (low) for the direction E2 to E1. SPEED provides an XOR'd output of the two sensors. Because of internal delays, DIRECTION will always be updated before SPEED and is updated at every transition of E1 OUTPUT and E2 OUTPUT (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 provide an OFF (high) at DIRECTION and an OFF (high) for E1 and E2 (internal) for magnetic fields less than BOP. This eliminates ambiguity when the device is powered up and either sensor detects a field between BOP and BRP. If either sensor is subjected to a field greater than BOP, the internal logic will set accordingly.
* "Pole" refers to a single pole (North or South) unless stated as "pole pair" (North and South).
6
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
3422 HALL-EFFECT, DIRECTION-DETECTION SENSOR
Applications 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 sensor-to-sensor 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 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 "HallEffect IC Applications Guide" which can be found in the latest issue of Application Note 27701, at www.allegromicro.com/techpub2/an/an27701
0.059" 1.50 mm
TARGET FACE WIDTH, F >1.50 SIN (mm) >0.059 SIN (inch)
1.50 COS (mm) 0.059 COS (inch)
Rotated Sensor for Fine-Pitch Ring Magnets
3
A
1 2
A
1 2 3 4 5
4 5
Dwg. MH-024
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7
3422 HALL-EFFECT, DIRECTION-DETECTION SENSOR
Criteria for Device Qualification Contact Allegro MicroSystems for qualification information.
Sensor Locations
ACTIVE AREA DEPTH 0.0165" 0.42 mm NOM
0.059" 1.50 mm
0.096" 2.44 mm
0.072" 1.83 mm E1 E2
Allegro
A
BRANDED SURFACE 1 2 3 4 5
Dwg. MH-007-1A
8
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
3422 HALL-EFFECT, DIRECTION-DETECTION SENSOR
Package Designator 'KA' Dimensions in Inches
(controlling dimensions)
0.252 0.247
Dimensions in Millimeters
(for reference only)
6.40 6.27
0.063 0.059
1.60 1.50
0.181 0.176 45 0.083
MAX 1 2 3 4 5
4.60 4.47 45 2.11
MAX 1 2 3 4 5
0.018
0.46
0.600 0.560
0.0173 0.0138
15.24 14.23
0.44 0.35
SEE NOTE
SEE NOTE
0.0189 0.0142
0.050
BSC
Dwg. MH-010H in
0.48 0.36
1.27
BSC
Dwg. MH-010H mm
Horizontal-Mount Lead Form (add `-TL' to part number)
0.095
0.005
2.41
0.13
0.002
MAX
0.051
MAX
0.004 0-8
MAX
0.020
MIN FLAT
Dwg. MH-015 in
0.10
MAX
0-8
0.51
MIN FLAT
Dwg. MH-015 mm
NOTES: 1. 2. 3. 4. 5. 6.
Tolerances on package height and width represent allowable mold offsets. Dimensions given are measured at the widest point (parting line). Exact body and lead configuration at vendor's option within limits shown. Height does not include mold gate flash. Recommended minimum PWB hole diameter to clear transition area is 0.035" (0.89 mm). Where no tolerance is specified, dimension is nominal. Supplied in bulk pack (500 pieces per bag).
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9
3422 HALL-EFFECT, DIRECTION-DETECTION SENSOR
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 products are not authorized for use as critical components in lifesupport appliances, devices, or systems without express written approval. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringements of patents or other rights of third parties that may result from its use.
10
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000

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