3185
THRU
3189
HALL-EFFECT LATCHES
FOR HIGH-TEMPERATURE OPERATION
These Hall-effect latches are extremely temperature-stable and stress-
resistant sensors especially suited for operation over extended temperature
ranges to +150°C. Superior high-temperature performance is made possible
through a novel Schmitt trigger circuit that maintains operate and release
point symmetry by compensating for temperature changes in the Hall ele-
ment. Additionally, internal compensation provides magnetic switch points
that become more sensitive with temperature, hence offsetting the usual
degradation of the magnetic field with temperature. The symmetry capability
makes these devices ideal for use in pulse-counting applications where duty
cycle is an important parameter. The four basic devices (3185, 3187, 3188,
and 3189) are identical except for magnetic switch points.
Each device includes on a single silicon chip a voltage regulator, qua-
dratic Hall-voltage generator, temperature compensation circuit, signal
amplifier, Schmitt trigger, and a buffered open-collector output to sink up to
25 mA. The on-board regulator permits operation with supply voltages of 3.8
to 24 volts.
The first character of the part number suffix determines the device
operating temperature range. Suffix ‘E–’ is for -40°C to +85°C, and suffix
‘L–’ is for -40°C to +150°C. Three package styles provide a magnetically
optimized package for most applications. Suffix ‘–LT’ is a miniature SOT-
89/TO-243AA transistor package for surface-mount applications; suffix ‘–U’
is a three-lead plastic mini-SIP, while suffix ‘–UA’ is a three-lead ultra-mini-
SIP.
Data Sheet
27609.2A
V
X
CC
1
2
3
GROUND
Dwg. PH-003A
Pinning is shown viewed from branded side.
ABSOLUTE MAXIMUM RATINGS
at T
A
= +25
°
C
Supply Voltage, V
CC
............................
30 V
Reverse Battery Voltage, V
RCC
...........
-30 V
Magnetic Flux Density, B ...........
Unlimited
Output OFF Voltage, V
OUT
..................
30 V
Reverse Output Voltage, V
OUT
..........
-0.5 V
Continuous Output Current, I
OUT
.....
25 mA
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
OUTPUT
SUPPLY
FEATURES
I
I
I
I
I
I
I
I
I
Symmetrical Switch Points
Superior Temperature Stability
Operation From Unregulated Supply
Open-Collector 25 mA Output
Reverse Battery Protection
Activate With Small, Commercially Available Permanent Magnets
Solid-State Reliability
Small Size
Resistant to Physical Stress
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.,
A3185ELT
.
ALLEGRO [ ALLEGRO MICROSYSTEMS ]
