3046 Datasheet, PDF (2/8 Pages) Allegro MicroSystems – HALL EFFECT GEAR-TOOTH SENSORS ZERO SPEED

3046, 3056, AND 3058
HALL EFFECT
GEAR-TOOTH SENSORS
–ZERO SPEED
All devices, when used with a back-
biasing 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 mea-
surement 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
1 SUPPLY
REG
+
–
X
X
OUTPUT
3
2
GROUND
Dwg. FH-010
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.
ELECTRICAL CHARACTERISTICS at V_CC = 8 V, over operating temperature range.
Characteristic
Symbol
Test Conditions
Min.
Limits
Typ. Max.
Supply Voltage
Power-Up State
Output Saturation Voltage
Output Leakage Current
Supply Current
Output Rise time
Output Fall time
V_CC
—
V_OUT(SAT)
I_OFF
I_CC
t_r
t_f
Operating
3058* only,
V_CC = 0 4.5 V, B < B_OP
I_OUT = 20 mA, B > B_OP
V_CC = V_OUT = 24 V, B < B_RP
V_CC = 24 V, B < B_RP
R_L = 820 Ω, C_L = 20 pF
R_L = 820 Ω, C_L = 20 pF
4.5
—
24
Output is OFF
—
135
400
—
—
5.0
—
7.2
14
—
100
—
—
100
—
Units
V
—
mV
µA
mA
ns
ns
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
Copyright © 1989, 1995 Allegro MicroSystems, Inc.