3250
PROGRAMMABLE, CHOPPER-
STABILIZED, HALL-EFFECT SWITCH
The A3250x and A3251x programmable switches provide tooth/
valley recognition in large gear-tooth sensing, high-temperature appli-
cations. Each sensor consists of a single element, chopper-stabilized
Hall-effect IC that can be programmed to the desired magnetic switch
point, optimizing sensor airgap and timing accuracy performance after
final packaging. The small package can be easily assembled and used
in conjunction with a wide variety of gear/target shapes and sizes. The
A3250x output turns on in the presence of a sufficiently large south-
pole magnetic field while the A3251x turns off with a sufficiently large
south-pole magnetic field.
3
Data Sheet
27621.41
X
PTCT
V
CC
1
2
GROUND
OUTPUT
SUPPLY
The sensing technology used for these sensors 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, minimizes 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.
These sensor systems are ideal for use in gathering speed, position,
and timing information using gear-tooth-based configurations. They are
particularly suited to those applications that require accurate duty cycle
control or accurate edge detection. The lower vibration sensitivity also
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Dwg. PH-003-2
PRELIMINARY INFORMATION
(subject to change without notice)
March 20, 2000
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, V
CC
........................
26.5 V*
Reverse Supply Voltage, V
RCC
............
-18 V
Output OFF Voltage, V
OUT
.....................
V
CC
Output Current, I
OUT
.....
Internally Limited
Over-Voltage Supply Current, I
CC
...
100 mA
Magnetic Flux Density, B ............
Unlimited
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
*Fault conditions that produce supply voltage
transients will be clamped by an internal Zener
diode. These conditions can be tolerated but
should be avoided.
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.,
A3250LLT .
SANKEN [ SANKEN ELECTRIC ]
