A1245 Datasheet, PDF (1/13 Pages) Allegro MicroSystems – Chopper-Stabilized, Two Wire Hall-Effect Latch

A1245
Chopper-Stabilized, Two Wire Hall-Effect Latch
FEATURES AND BENEFITS
• High speed, 4-phase chopper stabilization
□□Low switchpoint drift throughout temperature range
□□Low sensitivity to thermal and mechanical stresses
• On-chip protection
□□Supply transient protection
□□Reverse battery protection
• On-board voltage regulator
□□3.0 to 24 V operation
• Solid-state reliability
• Industry leading ISO 7637-2 performance through use of
proprietary, 40 V clamping structures
PACKAGES:
Not to scale
Approximate
footprints
DESCRIPTION
The A1245 is a two-wire Hall-effect latch. The device is
produced on theAllegro^™ advanced BiCMOS wafer fabrication
process, which implements a patented high frequency, 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.
Two-wire latches are particularly advantageous in cost-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.
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
packages (SIP) for through-hole mounting. Both packages are
lead (Pb) free, with 100% matte tin leadframe plating.
3-pin ultramini SIP
1.5 × 4 × 3 mm
(suffix UA)
3-pin SOT23-W
2 × 3 × 1 mm
(suffix LH)
VCC
V+
Regulator
To all subcircuits
Clock/Logic
Amp
Low-Pass
Filter
Schmitt
Trigger
Polarity
A1245-DS, Rev. 1
GND
UA package only
GND
Functional Block Diagram