A1244
Chopper-Stabilized, Two Wire Hall-Effect Latch
Features and Benefits
Description
▪ High speed, 4-phase chopper stabilization
▫ Low switchpoint drift throughout temperature range
▫ Low sensitivity to thermal and mechanical stresses
▪ On-chip protection
The A1244 is a two-wire Hall-effect latch. The devices are
producedontheAllegro® advancedBiCMOSwaferfabrication
process,whichimplementsapatentedhighfrequency,4-phase,
chopper-stabilization technique. This technique achieves
magnetic stability over the full operating temperature range,
and eliminates offsets inherent in devices with a single Hall
element that are exposed to harsh application environments.
▫ Supply transient protection
▫ Reverse battery protection
▪ On-board voltage regulator
▫ 3.0 to 24 V operation
▪ Solid-state reliability
▪ Robust EMC and ESD performance
▪ Industry leading ISO 7637-2 performance through use of
proprietary, 40-V clamping structures
Two-wirelatchesareparticularlyadvantageousincost-sensitive
applications because they require one less wire for operation
versus the more traditional open-collector output switches.
Additionally, the system designer inherently gains diagnostics
because there is always output current flowing, which should
be in either of two narrow ranges.Any current level not within
these ranges indicates a fault condition.
Packages:
3-pin ultramini SIP
1.5 mm × 4 mm × 3 mm
(suffix UA)
3-pin SOT23-W
2 mm × 3 mm × 1 mm
(suffix LH)
The Hall-effect latch will be in the high output current state
in the presence of a magnetic south polarity field of sufficient
magnitude and will remain in this state until a sufficient north
polarity field is present.
The device is offered in two package styles. The LH is a
SOT-23W style, miniature low profile package for surface-
mount applications. The UA is a 3-pin ultra-mini single inline
package (SIP) for through-hole mounting. Both packages are
lead (Pb) free, with 100% matte tin leadframe plating.
Approximate footprint
Not to scale
Functional Block Diagram
V+
VCC
Regulator
Clock/Logic
Amp
To all subcircuits
0.01 μF
Schmitt
Trigger
Low-Pass
Filter
Polarity
GND
UA package only
GND
A1244-DS, Rev. 1