A3421: Hall-Effect Direction Detection Sensor IC

PRELIMINARY INFORMATION
(subject to change without notice)
September 6, 2000
E1
E2
X
X
DIRECTION-DETECTION SENSOR ICS
T
C
2
3
4
5
GROUND
E1 OUTPUT
SPEED
a
is DU ;
A
A
O
K
K
R
x
x
P
1
2
2 D 42 t.
4
3
3
e
E
e
A
A
U
h
e
s
e
N th ta
I
h
T NT by da
r
d
O
e
e at
c
C
IS pla e l
DIRECTION
SUPPLY
1
HALL-EFFECT,
The A3421xKA and A3422xKA Hall-effect, direction-detection
sensor ICs are a new generation of special-function devices 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 100 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
A3421xKA is a high-hysteresis device designed for low-resolution
pulse counting while the A3422xKA is a high-sensitivity device
optimized for use with high-density magnets.
LOGIC
VCC
Data Sheet
27650.1
3421 AND
3422
Dwg. PH-015
Pinning is shown viewed from branded side.
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
D Re
Operating Temperature Range, TA
Suffix ‘EKA’ . . . . . . . -40˚C to +85˚C
Suffix ‘LKA’ . . . . . . -40˚C to +150˚C
Storage Temperature Range,
TS . . . . . . . . . . . . . . . -65˚C 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 a 4.5 V to 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 of -40°C to +85°C,
suffix ‘L–’ is for the automotive and military temperature range of
-40°C to +150°C. The 5-pin ‘KA’ SIP package provides a costcompetitive solution to linear magnetic sensing in harsh environments.
FEATURES
■
■
■
■
se
Internal Direction-Decoding Circuitry
Two Matched Hall Latches On A Single Substrate
Superior Temperature Stability
4.5 V to 18 V Operation
Electrically Defined Power-On State
Under-Voltage Lockout
Always order by complete part number, e.g., A3421EKA .
3421 AND 3422
HALL-EFFECT,
DIRECTION-DETECTION
SENSOR ICS
FUNCTIONAL BLOCK DIAGRAM
REG
UVLO
E1
X
X
SUPPLY
POWER-ON
LOGIC
LOGIC
1
2
DIRECTION
3
GROUND
4
E1 OUTPUT
5
SPEED
E2
Dwg. FH-018
+B
BOP1
0
BRP1
-B
+B
0
-B
BOP2
BRP2
CHANGE IN DIRECTION
TIMING DIAGRAM
OUT E1
OUT E2
(INTERNAL)
SPEED
(OUT E1 XOR OUT E2)
td
DIRECTION
Dwg. WH-012A
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 1999 Allegro MicroSystems, Inc.
3421 AND 3422
HALL-EFFECT,
DIRECTION-DETECTION
SENSOR ICS
ELECTRICAL CHARACTERISTICS over operating temperature range.
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Supply Voltage Range
VCC
Operating, TJ < 165°C1
4.5
—
18
V
Output Leakage Current
IOFF
VOUT = VCC = 18 V
—
<1.0
10
µA
IOUT = 20 mA
—
0.21
0.50
V
OFF
OFF
OFF
—
Output Saturation Voltage
Power-On State
VOUT(SAT)
VCC = 0 → 5 V,
BRP1 < B < BOP1, BRP2 < B < BOP2
POS
Under-Voltage Lockout
VCC(UV)
IOUT = 20 mA, VCC = 0 → 5 V
—
3.5
—
V
Under-Voltage Hysteresis
VCC(hys)
Lockout (VCC(UV)) - Shutdown
—
0.5
—
V
Power-On Time
tpo
VCC > 4.5 V
—
—
50
µs
Output Rise Time
tr
CL = 20 pF, RL = 820 Ω
—
200
—
ns
Output Fall Time
tf
CL = 20 pF, RL = 820 Ω
—
200
—
ns
Direction Change Delay
td
CL = 20 pF, RL = 820 Ω
0.5
1.0
5.0
µs
VCC = 8 V, All outputs OFF
5.0
9.0
18
mA
Supply Current
ICC
ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS
NOTES:1. Maximum supply voltage must be adjusted for power dissipation and ambient temperature.
2. Typical Data is at VCC = 12 V and TA = +25°C and is for design information only.
0.6
0.5
0.4
0.3
RθJA = 164°C/W
0.2
0.1
0
25
50
75
100
125
TEMPERATURE IN ° C
150
175
Dwg. GH-069
3421 AND 3422
HALL-EFFECT,
DIRECTION-DETECTION
SENSOR ICS
MAGNETIC CHARACTERISTICS over operating voltage range.
A3421xKA
Characteristic
Symbol
Operate Point
BOP
Release Point3
Hysteresis
BRP
Bhys
A3422xKA
Test Conditions
Min.
Typ.
Max.
Min.
Typ.
Max.
Units
TA = -40°C
140
185
300
—
29
85
G
TA = +25°C
130
160
280
—
29
75
G
TA = Maximum
120
—
260
—
—
75
G
TA = -40°C
-300
-190
-140
-85
-19
—
G
TA = +25°C
-280
-175
-130
-75
-18
—
G
TA = Maximum
-260
—
-120
-75
-16
—
G
TA = -40°C
280
375
—
10
48
—
G
TA = +25°C
260
335
—
10
46
—
G
TA = Maximum
240
—
—
10
—
—
G
Operate Differential
BOP1 - BOP2
—
—
±80
—
—
±60
G
Release Differential
BRP1 - BRP2
—
—
±80
—
—
±60
G
NOTES:1. Magnetic flux density is measured at most sensitive area of device,
nominally located 0.014” (0.37 mm) below the branded face of the package.
2. Typical Data is at VCC = 12 V and TA = +25°C and is for design information only.
3. As used here, negative flux densities are defined as less than zero (algebraic convention).
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
3421 AND 3422
HALL-EFFECT,
DIRECTION-DETECTION
SENSOR ICS
TYPICAL A3421xKA CHARACTERISTICS
500
250
200
150
400
V
=8V
CC
100
HYSTERESIS IN GAUSS
SWITCH POINTS IN GAUSS
OPERATE POINT
50
0
V
=8V
CC
-50
-100
RELEASE POINT
-150
300
200
100
-200
-250
-50
-25
0
25
50
75
100
AMBIENT TEMPERATURE IN ° C
125
0
150
-50
-25
0
25
50
75
100
125
AMBIENT TEMPERATURE IN ° C
Dwg. GH-026-2
150
Dwg. GH-051-2
TYPICAL A3422xKA CHARACTERISTICS
100
50
40
80
OPERATE POINT
20
HYSTERESIS IN GAUSS
SWITCH POINTS IN GAUSS
30
10
0
V
=8V
CC
-10
RELEASE POINT
-20
-30
V
=8V
CC
60
40
20
-40
-50
-50
-25
0
25
50
75
100
AMBIENT TEMPERATURE IN ° C
125
150
Dwg. GH-026-1
0
-50
-25
0
25
50
75
AMBIENT TEMPERATURE IN ° C
100
125
150
Dwg. GH-051-1
3421 AND 3422
HALL-EFFECT,
DIRECTION-DETECTION
SENSOR ICS
TYPICAL ELECTRICAL CHARACTERISTICS
300
10
SUPPLY CURRENT IN mA
9.0
200
150
100
ALL OUTPUTS ON
8.0
ALL OUTPUTS OFF
7.0
50
0
-50
-25
0
25
50
100
75
AMBIENT TEMPERATURE IN ° C
6.0
150
125
-50
-25
0
25
Dwg. GH-029-2
12
T = 25°C
A
11
10
ALL OUTPUTS ON
9.0
8.0
ALL OUTPUTS OFF
7.0
6.0
5.0
2.0
6.0
50
75
AMBIENT TEMPERATURE IN ° C
13
SUPPLY CURRENT IN mA
SATURATION VOLTAGE IN mV
V
=8V
CC
I OUT = 20 mA
250
10
14
18
SUPPLY VOLTAGE IN VOLTS
Dwg. GH-058-3
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
100
125
150
Dwg. GH-053-1
3421 AND 3422
HALL-EFFECT,
DIRECTION-DETECTION
SENSOR ICS
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 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 element-to-element spacing, and,
to a lesser extent, the magnetic switch points. For optimal
design, the device 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 Τ) is then four times the element-to-element
spacing. A quadrature relationship can also be maintained
for a ring magnet that has a period that satisfies the relationship nΤ/4 = 1.5 mm, where n is any odd integer.
Therefore, ring magnets with pole-pair spacings 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 elements.
*“Pole” refers to a single pole (North or South) unless
stated as “pole pair” (North and South).
Outputs. The device provides three saturated outputs:
DIRECTION, E1 OUTPUT, and SPEED. DIRECTION
provides the direction output of the device 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 elements. 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 circutry 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 element detects a field between B
OP
and BRP. If either element is subjected to a field greater than
BOP, the internal logic will set accordingly.
3421 AND 3422
HALL-EFFECT,
DIRECTION-DETECTION
SENSOR ICS
APPLICATIONS INFORMATION
Operation with Fine-Pitch Ring Magnets. For
targets with a circular pitch of less than 4mm, a performance improvement can be observed by rotating the front
face of the device (see below). This device rotation
decreases the effective 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 Hall elements) 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 devices is
also available in the “Hsall-Effect IC Applications Guide”
which can be found in the latest issue of the Allegro
MicroSystems Electronic Data Book, AMS-702 or Application Note 27701, or at
1.50 COS α (mm)
0.059 COS α (inch)
www.allegromicro.com
0.059"
1.50 mm
α
Rotated device for
fine-pitch ring
magnets
A
TARGET FACE WIDTH, F
>1.50 SIN α (mm)
>0.059 SIN α (inch)
1
2
3
A
2
3
4
5
4
1
5
Dwg. MH-024
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
3421 AND 3422
HALL-EFFECT,
DIRECTION-DETECTION
SENSOR ICS
CRITERIA FOR DEVICE QUALIFICATION
All Allegro devices are subjected to stringent qualification requirements prior to being released to production. To
become qualified, except for the destructive ESD tests, no failures are permitted.
Qualification Test
Test Method and
Test Conditions
Test Length
Samples
Per Lot
Temperature Humidity
Bias Life
JESD22-A101,
TA = 85°C, RH = 85%
1000 hrs
77
Bias Life
JESD22-A108,
TA = 150°C, TJ = 165°C
1000 hrs
77
(Surge Operating Life)
JESD22-A108,
TA = 175°C, TJ = 190°C
1000 hrs
77
Autoclave, Unbiased
JESD22-A102,
TA = 121°C, 15 psig
96 hrs
77
High-Temperature
(Bake) Storage Life
JESD22-A103,
TA = 170°C
1000 hrs
77
Temperature Cycle
JESD22-A104
1000 cycles
77
-55°C to +150°C
ESD,
Human Body Model
CDF-AEC-Q100-002
Pre/Post
Reading
3 per
test
Test to failure
All leads > 8 kV
Comments
Device biased for
minimum power
ELEMENT LOCATIONS
(±0.005” [0.13 mm] die placement)
ACTIVE AREA DEPTH
0.014"
0.37 mm
NOM
0.059"
1.50 mm
0.096"
2.44 mm
0.072"
1.83 mm
E1
E2
A
BRANDED
SURFACE
1
2
3
4
5
Dwg. MH-007-1
3421 AND 3422
HALL-EFFECT,
DIRECTION-DETECTION
SENSOR ICS
PACKAGE DESIGNATOR 'KA'
Dimensions in Inches
Dimensions in Millimeters
(controlling dimensions)
(for reference only)
6.40
6.27
0.252
0.247
1.60
1.50
0.063
0.059
4.60
4.47
0.181
0.176
45°
45°
0.083
MAX
1
2
3
4
0.018
5
2.11
MAX
0.600
0.560
1
2
3
4
0.46
5
15.24
14.23
0.015
0.38
SEE NOTE
SEE NOTE
0.050
0.016
1.27
0.41
BSC
BSC
Dwg. MH-010G mm
Dwg. MH-010G in
SURFACE-MOUNT LEAD FORM (Suffix '-TL')
2.41
0.095
±0.13
±0.005
0.051
0.002
MAX
MAX
0.004 0°–8°
MAX
0.10
0.020
MIN
FLAT
MAX
Dwg. MH-015 in
0°–8°
0.51
MIN
FLAT
Dwg. MH-015 mm
NOTES: 1. Tolerances on package height and width represent allowable mold offsets. Dimensions given are measured at the widest point (parting line).
2. Exact body and lead configuration at vendor’s option within limits shown.
3. Height does not include mold gate flash.
4. Recommended minimum PWB hole diameter to clear transition area is 0.035” (0.89 mm).
5. Where no tolerance is specified, dimension is nominal.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
3421 AND 3422
HALL-EFFECT,
DIRECTION-DETECTION
SENSOR ICS
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 design of its products.
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 which may result
from its use.
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