A1225LLTTR-T Ver la hoja de datos (PDF) - Allegro MicroSystems

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A1225LLTTR-T

Hall Effect Latch for High Temperature Operation

Allegro MicroSystems 

A1225, A1227, and A1229

Hall Effect Latch for High Temperature Operation

Features and Benefits

▪ Symmetrical switchpoints

▪ Superior temperature stability

▪ Operation from unregulated supply

▪ Open-drain 25 mA output

▪ Reverse Battery protection

▪ Activate with small, commercially available

permanent magnets

▪ Solid-state reliability

▪ Small size

▪ Resistant to physical stress

▪ Enhanced ESD structures result in 8 kV HBM ESD

performance without external protection components

▪ Internal protection circuits enable 40 V load dump

compliance without external protection components

Packages: 3-pin SOT89 (suffix LT) and

3-pin SIP (suffix UA)

Not to scale

Description

These Hall-effect latches are extremely temperature-stable

and stress resistant sensor ICs 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 element. Additionally, internal compensation

provides magnetic switchpoints 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 three basic

devices (A1225, A1227, and A1229) are identical except for

magnetic switchpoints.

Each device includes on a single silicon chip a voltage regulator,

Hall-voltage generator, temperature compensation circuit,

signal amplifier, Schmitt trigger, and a buffered open-drain

output to sink up to 25 mA. The on-board regulator permits

operation with supply voltages of 3.8 to 24 V.

The first character of the part number suffix determines the

device operating temperature range. Suffix L is for –40°C to

150°C. Two package styles provide a magnetically optimized

package for most applications. Suffix LT is a miniature SOT89/

TO-243AA transistor package for surface-mount applications,

suffix UAis a three-lead ultra-mini-SIP. Both packages are lead

(Pb) free with 100% matte tin leadframe plating.

Functional Block Diagram

VCC

Regulator

Clock / Logic

To All Subcircuits

VOUT

A1225-DS

AMP

Anti-aliasing

LP-Filter

Tuned Filter

GND

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