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Allegro MicroSystems |
3150
PROGRAMMABLE, CHOPPER-
STABILIZED, HALL-EFFECT SWITCH
The A3150JLT and A3150JUA programmable switches provide
tooth/valley recognition in large gear-tooth sensing applications. Each
sensor consists of a single element, chopper-stabilized Hall-effect IC
that can be programmed to the desired magnetic switch point, opti-
mizing sensor airgap and timing accuracy performance after final
PTCT
packaging. The small package can be easily assembled and used in
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PRODE ONsLiYgnDwg.PH-003-2
ED NC dePRELIMINARY INFORMATION
U E(subject to change without notice)
IN R wApril 12, 1999
NT FE r neABSOLUTE MAXIMUM RATINGS
CO RE foat TA = 25°C
Supply Voltage, VCC ........................... 26.5 V
0Reverse Supply Voltage, VRCC ............ -30 V
IS R 5Overvoltage Supply Current, ICC ..... 100 mA
D O 2Magnetic Flux Density, B ............ Unlimited
F 3Output Current, IOUT ..... Internally Limited
Output OFF Voltage, VOUT ................. 26.5 V
AReverse Output Current, IROUT ......... -50 mA
— eOperating Temperature Range,
TA ............................... -40°C to +115°C
UsStorage Temperature, TS ................... +170°C
conjunction with a wide variety of gear/target shapes and sizes. The
two devices differ only in package style.
The sensing technology used for this sensor is Hall-effect based.
The sensor incorporates a single-element Hall IC that switches in
response to magnetic signals created by a ferrous target. The program-
mability of the circuit eliminates magnet and system offsets such as
those caused by tilt yet provides zero-speed detection capabilities
without the associated running jitter inherent in classical digital solu-
tions.
A proprietary dynamic offset cancelation technique, with an
internal high-frequency clock, reduces the residual offset voltage,
which is normally caused by device overmolding, temperature
dependancies, and thermal stress. This technique produces devices that
have an extremely stable quiescent output voltage, are immune to
mechanical stress, and have precise recoverability after temperature
cycling. Many problems normally associated with low-level analog
signals are minimized by having the Hall element and amplifier in a
single chip. Output precision is obtained by internal gain adjustments
during the manufacturing process and operate-point programming in the
user’s application.
This sensor system is ideal for use in gathering speed, position, and
timing information using gear-tooth-based configurations. The
A3150JLT/JUA are particularly suited to those applications that require
accurate duty cycle control or accurate edge detection. The lower
vibration sensitivity also makes these devices extremely useful for
transmission speed sensing.
Continued next page
Always order by complete part number: the prefix 'A' + the basic four-digit
part number + a suffix to indicate operating temperature range +
a suffix to indicate package style, e.g., A3150JLT .
3150
PROGRAMMABLE, CHOPPER-
STABILIZED, PRECISION,
HALL-EFFECT SWITCH
FUNCTIONAL BLOCK DIAGRAM
1 SUPPLY
PROGRAM
LOGIC
REG.
OFFSET
ADJUST
POWER-UP
OUTPUT
X3
CONTROL
CURRENT
LIMIT
<1Ω
GROUND
2
Dwg. FH-020-3
Two package styles provide a magnetically opti-
mized package for most applications. Suffix ‘–LT’ is a
miniature SOT-89/TO-243AA transistor package for
surface-mount applications; while suffix ‘–UA’ is a
three-lead ultra-mini-SIP for through-hole mounting.
FEATURES AND BENEFITS
s Chopper Stabilized for
Extremely Low Switch-Point Drift and
Immunity to Mechanical Stress
s Externally Programmed Switch Point
s On-Chip Supply-Transient Protection
s Output Short-Circuit Protection
s Single-Chip Sensing IC for High Reliability
s Small Mechanical Size
s <50 µs Power-On Time
s Wide Operating Voltage Range
s Defined Power-On State
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2000, Allegro MicroSystems, Inc.
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