3185 THRU 3189
HALL-EFFECT LATCHES
FOR HIGH-TEMPERATURE
OPERATION
SENSOR LOCATIONS
(±0.005 [0.13 mm] die placement)
OPERATION
In operation, the output transistor is OFF until the strength of the mag-
netic field perpendicular to the surface of the chip exceeds the threshold or
operate point (BOP). When the field strength exceeds BOP, the output transis-
tor switches ON and is capable of sinking 25 mA of current.
Package Designators “LT”
ACTIVE AREA DEPTH
0.0305"
0.090"
The output transistor switches OFF when magnetic field reversal results
in a magnetic flux density below the OFF threshold (BRP). This is illustrated
in the transfer characteristics graph (A3187* shown).
0.775 mm
2.27 mm
NOM
0.050"
1.27 mm
Note that the device latches; that is, a south pole of sufficient strength
will turn the device ON. Removal of the south pole will leave the device ON.
The presence of a north pole of sufficient strength is required to turn the
device OFF.
A
1
2
3
Dwg. MH-008-4C
V
Package Designator “U”
BB
30 V
MAX
ACTIVE AREA DEPTH
0.0165"
0.42 mm
NOM
0.092"
2.33 mm
0.077"
1.96 mm
B
B
OP
RP
A
V
OUT(SAT)
BRANDED
SURFACE
0
1
2
3
-B
0
+B
FLUX DENSITY
Dwg. GH-034-4
Dwg. MH-002-7C
The simplest form of magnet that will operate these devices is a ring
magnet, as shown below. Other methods of operation are possible.
Package Designators “UA” and "UA-TL"
ACTIVE AREA DEPTH
0.0195"
0.083"
0.50 mm
2.10 mm
NOM
0.060"
1.51 mm
A
BRANDED
SURFACE
1
2
3
Dwg. A-11,899
Dwg. MH-011-4C
APPLICATIONS INFORMATION
Although sensor location is accurate to three
sigma for a particular design, product improve-
ments may result in small changes to sensor
location.
Extensive applications information on magnets and Hall-effect sensors is
also available in the Allegro Integrated and Discrete Semiconductors Data
Book or Application Note 27701.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
SANKEN [ SANKEN ELECTRIC ]
