HALL-EFFECT LATCHES

FOR HIGH-TEMPERATURE OPERATION

These Hall-effect latches are extremely temperature-stable and stress-

resistant sensors 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 ele-

ment. Additionally, internal compensation provides magnetic switch points

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 four basic devices (3185, 3187, 3188,

and 3189) are identical except for magnetic switch points.

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

dratic Hall-voltage generator, temperature compensation circuit, signal

amplifier, Schmitt trigger, and a buffered open-collector output to sink up to

25 mA. The on-board regulator permits operation with supply voltages of 3.8

to 24 volts.

The first character of the part number suffix determines the device

operating temperature range. Suffix ‘E–’ is for -40

°C to +85°C, and suffix

‘L–’ is for -40

°C to +150°C. Three package styles provide a magnetically

optimized package for most applications. Suffix ‘–LT’ is a miniature SOT-

89/TO-243AA transistor package for surface-mount applications; suffix ‘–U’

is a three-lead plastic mini-SIP, while suffix ‘–UA’ is a three-lead ultra-mini-

SIP.

ABSOLUTE MAXIMUM RATINGS

Magnetic Flux Density, B ........... Unlimited

Suffix ‘E–’ ................... -40

Suffix ‘L–’ ................. -40

Storage Temperature Range,

FEATURES

I Symmetrical Switch Points

I Superior Temperature Stability

I Operation From Unregulated Supply

I Open-Collector 25 mA Output

I Reverse Battery Protection

I Activate With Small, Commercially Available Permanent Magnets

I Solid-State Reliability

I Small Size

I Resistant to Physical Stress

Pinning is shown viewed from branded side.

Always order by complete part number: the prefix ‘A’ + the basic four-digit

part number + a suffix to indicate operating temperature range +

a suffix to indicate package style, e.g., A3185ELT .

3189

Dwg. PH-003A

1

V

CC

3

2