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 sens-
ing 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 ma-
jor manufacturing hurdles encountered in
fi
ne-pitch direction-detection
applications, namely maintaining accurate mechanical location between
the two active Hall elements. Here, the two Hall elements are photo-
lithographically aligned to better than 1
μm,
as contrasted with 100
μm
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 auto-
motive or industrial applications. The A3422xKA is a high-sensitivity
device optimized for use with high-density magnets.
The A3422xKA monolithic integrated circuit contains two inde-
pendent Hall-effect bipolar switches whose digital outputs are internally
coupled to CMOS logic circuitry that decodes signal speed and direc-
tion. 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-col-
lector outputs.
Two operating temperature ranges are provided; suffix ‘E–’ is for
the automotive and industrial temperature range of -40°C to +85°C, suf-
fi
x ‘L–’ is for the automotive and military temperature range of
-40°C to +150°C. The 5-pin ‘KA’ SIP package provides a cost-com-
petitive 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, V
CC
. . . . . . . . . . . . . .
18 V
Magnetic Flux Density, B . . . .
Unlimited
Output OFF Voltage, V
OUT
. . . . . . . . .
V
CC
Output Sink Current, I
OUT
. . . . . . .
30 mA
Package Power Dissipation,
P
D
. . . . . . . . . . . . . . . . . . . . .
500 mW
Operating Temperature Range, T
A
Suffix ‘E–’ . . . . . . . . .
-40°C to +85°C
Suffix ‘L–’ . . . . . . . .
-40°C to +150°C
Storage Temperature Range,
T
S
. . . . . . . . . . . . . .
-65°C to +170°C
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
1
Pb-based
Pb-Free
1
Yes
Yes
Packing
2
Bulk, 500 pieces/bag
Bulk, 500 pieces/bag
Mounting
5-pin SIP through hole
5-pin SIP through hole
Ambient, T
A
(°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.
2
Contact 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
t
d
DIRECTION
Dwg. WH-012A
+B
0
B
OP1
B
RP1
-B
+B
0
B
RP2
-B
B
OP2
OUT
E1
OUT
E2
(INTERNAL)
SPEED
(OUT
E1
XOR OUT
E2
)
2
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2001, 2003 Allegro MicroSystems, Inc.
3422
HALL-EFFECT,
DIRECTION-DETECTION
SENSOR
MAGNETIC CHARACTERISTICS over operating voltage range.
Limits
Characteristic
Operate Point
Symbol
B
OP
Test Conditions
T
A
= -40°C
T
A
= +25°C
T
A
= Maximum
Release Point
3
B
RP
T
A
= -40°C
T
A
= +25°C
T
A
= Maximum
Hysteresis
B
hys
T
A
= -40°C
T
A
= +25°C
T
A
= Maximum
Operate Differential
Release Differential
—
—
B
OP1
- B
OP2
B
RP1
- B
RP2
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 V
CC
= 12 V and T
A
= +25°C 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
京公网安备 11010802033920号
EEWORLD
