A1225, A1227, and A1229
Hall Effect Latch for High Temperature Operation
Features and Benefits
▪ Symmetrical switchpoints
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
makesthesedevicesidealforuseinpulse-countingapplications
where duty cycle is an important parameter. The three basic
devices (A1225, A1227, and A1229) are identical except for
magnetic 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
Eachdeviceincludesonasinglesiliconchipavoltageregulator,
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.
Packages:
3-pin SIP
(suffix UA)
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
packageformostapplications.SuffixLTisaminiatureSOT89/
TO-243AAtransistorpackageforsurface-mountapplications,
suffixUAisathree-leadultra-mini-SIP.Bothpackagesarelead
(Pb) free with 100% matte tin leadframe plating.
3-pin SOT89
(suffix LT)
Not to scale
Functional Block Diagram
Regulator
VCC
To All Subcircuits
Clock / Logic
VOUT
AMP
Anti-aliasing
LP-Filter
Tuned Filter
GND
A1225-DS, Rev. 1