HALL EFFECT GEAR-TOOTH SENSORS
X X
V
CC
1
SUPPLY
Pinning is shown viewed from branded side.
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VCC. . . . . . . . . . . . . . 28 V
Reverse Battery Voltage,
V
. . . . . . . . . . . . . . . . . . . . . . -30 V
RCC
Magnetic Flux Density, B . . . . . Unlimited
Output OFF Voltage, V
Reverse Output Voltage, V
Output Current, I
Package Power Dissipation, P
Operating Temperature Range, T
Suffix “EU” . . . . . . . . . -40°C to +85°C
Suffix “LU” . . . . . . . . -40
Storage Temperature Range,
TS. . . . . . . . . . . . . . . -65°C to +170°C
OUT
. . . . . . . . . . . . 25 mA
OUT
32
GROUND
Dwg. PH-012
OUTPUT
. . . . . . . . . 28 V
. . . . . -0.5 V
OUT
. . 500 mW
D
A
°C to +150°C
3046, 3056, AND
3058
–ZERO SPEED
The A3046EU/LU, A3056EU/LU, and A3058EU/LU Hall effect
gear-tooth sensors are monolithic integrated circuits that switch in
response to differential magnetic fields created by ferrous targets.
These devices are ideal for use in gear-tooth-based speed, position,
and timing applications and operate down to zero rpm over a wide
range of air gaps and temperatures. When combined with a backbiasing magnet and proper assembly techniques, devices can be
configured to give 50% duty cycle or to switch on either leading,
trailing, or both edges of a passing gear tooth or slot.
The six devices differ only in their magnetic switching values and
operating temperature ranges. The low hysteresis of the A3046/56EU
and A3046/56LU makes them perfectly suited for ABS (anti-lock brake
system) or speed sensing applications where maintaining large air
gaps is important. The A3046EU/LU features improved switch point
stability with temperature over the A3056EU/LU. The high hysteresis
of the A3058EU and A3058LU, with their excellent temperature
stability, makes them especially suited to ignition timing applications
where switch-point accuracy (and latching requirements) is extremely
important.
Continued next page...
BENEFITS
■ Senses Ferrous Targets Down to Zero RPM
■ Large Effective Air Gap
■ Wide Operating Temperature Range
■ Operation from Unregulated Supply
■ High-Speed Operation
■ Output Compatible With All Logic Families
■ Reverse Battery Protection
■ Solid-State Reliability
■ Resistant to Physical Stress
SELECTION GUIDE
Switching Hysteresis
15-90 G 150-250 G
Operating Temp. Range Device Type Number
-40°C to +85°C A3046EU A3058EU
A3056EU
-40°C to +150°C A3046LU A3058LU
A3056LU
Data Sheet
27612A†
3046, 3056, AND 3058
HALL EFFECT
GEAR-TOOTH SENSORS
–ZERO SPEED
All devices, when used with a backbiasing magnet, can be configured to turn ON
or OFF with the leading or trailing edge of a
gear tooth or slot. Changes in fields on the
magnet face caused by a moving ferrous
mass are sensed by two integrated Hall
transducers and are differentially amplified by
on-chip electronics. The on-chip temperature
compensation and Schmitt trigger circuitry
minimizes shifts in effective working air gaps
and switch points over temperature making
these devices ideal for use in ignition timing,
anti-lock braking systems, and speed measurement systems in hostile automotive and
industrial environments.
Each Hall effect digital Integrated circuit
includes two quadratic Hall effect sensing
elements, a voltage regulator, temperature
compensating circuitry, low-level amplifier,
Schmitt trigger, and an open-collector output
driver. The on-board regulator permits
operation with supply voltages of 4.5 to 24
volts. The output stage can switch up to 20
mA at conservatively specified repetition
rates to 20 kHz and is compatible with bipolar
and MOS logic circuits.
FUNCTIONAL BLOCK DIAGRAM
SUPPLY
1
REG
OUTPUT
3
+
–
X X
Both magnetic characteristics are available in a choice of two operat-
ing temperature ranges. Suffix EU devices have an operating range of
-40°C to +85°C while suffix LU devices feature an operating range of
-40°C to +150°C. All devices are packaged in a 3-pin plastic SIP.
2
GROUND
Dwg. FH-010
ELECTRICAL CHARACTERISTICS at VCC = 8 V, over operating temperature range.
Limits
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Supply Voltage V
Power-Up State — 3058* only, Output is OFF —
Output Saturation Voltage V
Output Leakage Current I
Supply Current I
Output Rise time t
Output Fall time t
CC
OUT(SAT)
OFF
CC
r
f
Operating 4.5 — 24 V
V
= 0 4.5 V, B < B
CC
I
= 20 mA, B > B
OUT
VCC = V
VCC = 24 V, B < B
RL = 820 Ω, CL = 20 pF — 100 — ns
RL = 820 Ω, CL = 20 pF — 100 — ns
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 1989, 1995 Allegro MicroSystems, Inc.
= 24 V, B < B
OUT
RP
OP
OP
RP
— 135 400 mV
— — 5.0 µA
— 7.2 14 mA
3046, 3056, AND 3058
HALL EFFECT
GEAR-TOOTH SENSORS
–ZERO SPEED
MAGNETIC CHARACTERISTICS in gauss at VCC = 8 V.
Part Numbers*
3046 3056 3058
Characteristic Test Conditions Min. Typ. Max. Min. Typ. Max. Min. Typ. Max.
Operate Point, B
OP
Output Switches OFF to ON, — — 150 — — 150 — — 250
TA = +25°C
Release Point, B
RP
Output Switches ON to OFF, -150 — — -150 — — -250 — —
TA = +25°C
Hysteresis, B
hys
Change in Trip Point, — — ±50 — — ±75 — — ±50
∆B
or ∆B
OP
RP
NOTES: 1. Magnetic switch points are specified as the
difference in magnetic fields at the two Hall
elements.
2. As used here, negative flux densities are
defined as less than zero (algebraic convention).
BOP-BRP, TA = +25°C 15 50 90 15 50 90 150 200 250
Over operating temperature range,
Ref. B
or BRP at TA = +25°C
OP
TYPICAL OPERATING CHARACTERISTICS
200
V = 8 V
CC
I = 20 mA
OUT
180
3. Typical values are at TA = +25°C.
* Complete part number includes the prefix
160
‘A’ and a suffix to identify operating temperature range and package style. See selection
guide.
10
9
8
7
SUPPLY CURRENT IN mA
6
B > B
B < B
T = +25°C
A
OP
RP
140
SATURATION VOLTAGE IN mV
120
100
-50
11
10
9
8
7
SUPPLY CURRENT IN mA
6
0
AMBIENT TEMPERATURE IN °C
50 100 150
Dwg. GH-033
V = 24 V
CC
B > B
OP
B < B
RP
5
0
510152025
SUPPLY VOLTAGE IN VOLTS
www.allegromicro.com
Dwg. GH-031
5
-50
0
AMBIENT TEMPERATURE IN °C
50 100 150
Dwg. GH-032