A1232 Datasheet, PDF (1/22 Pages) Allegro MicroSystems – Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOS

A1232
Ultra-Sensitive, Hall-Effect Speed and Direction Sensor with TPOS
FEATURES AND BENEFITS
• AEC Q100 automotive qualified
• Senses speed and direction of ring magnets
□□Two matched bipolar Hall-effect switches on a single
substrate
□□True Power-On State (TPOS): Recognizes hysteresis
region at power-on
• Superior temperature stability
• Internal regulator for 3.3 to 24 V operation
• Symmetrical, high-sensitivity switchpoints
• Automotive grade
□□Solid-state reliability
□□Integrated ESD diodes
□□Robust structures for EMC protection
□□Short-circuit protected outputs
□□Reverse battery protection
□□–40°C to +150°C operating range
Package: 8-pin TSSOP (suffix LE)
Not to scale
DESCRIPTION
The A1232 is a highly sensitive, temperature-stable magnetic
sensing device ideal for use in ring-magnet-based speed
and direction systems in harsh automotive and industrial
environments. It contains two bipolar, Hall-effect switches
precisely arranged 1.63 mm apart. The switch outputs are thus
in quadrature when interfaced with the proper ring magnet
design. Internal logic processes the resulting digital signals to
derive speed and direction information that is presented at the
device’s outputs, OUTPUT A and OUTPUT B.
The A1232 is designed for demanding, high-performance
motor commutation applications. The Hall elements are
photolithographically aligned to better than 1 μm. Accurately
locating the two Hall elements eliminates a major manufacturing
hurdle encountered in fine-pitch applications. The A1232 also
has true power-on state (TPOS), the ability to detect when
it is in the hysteresis band, beyond B_OP , or below B_RP at
power-on. This provides reduced angle accuracy error due to
missed start-up edges.
Post-assembly factory programming at Allegro provides
sensitive, symmetrical switchpoints for both switches.
Extremely low-drift amplifiers maintain this symmetry. The
Allegro® patented, high-frequency chopper stabilization
technique cancels offsets in each channel and allows for
increased signal-to-noise ratio at the input of the internal
comparators. This leads to stable operation across the
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VCC
Programmable
Trim
4 Bit
LDO Regulator
GND
Channel A
2 Bit
Hall
Element
E1
Dynamic Offset
Cancellation
Hall
Amp.
Low-
Pass
Filter
Low Noise Signal
Recovery
Output Drive and
High Resolution
Speed Logic
OUTPUT A
(Speed)
Channel B
2 Bit
Hall
Element
E2
Dynamic Offset
Cancellation
Hall
Amp.
Low-
Pass
Filter
Low Noise Signal
Recovery
A1232-DS, Rev. 1
Functional Block Diagram
Output Drive and
Direction Logic
OUTPUT B
(Direction)