A3121 Ìæ»»ÐͺŠA1106

A3121, A3122, and A3123
Hall-Effect Switches for High-Temperature
DATASHEET PDF

3121.pdf

The 3121, 3122, and 3123 have been phased out of production as of October 31, 2005, and have been replaced by the A1106 next-generation continuous-time unipolar switch.

For samples and information on the replacement part, please refer to the A110x family.

Replacement Device Characteristics Table

Features

• Superior Temp. Stability for Automotive or Industrial Applications
• 4.5 V to 24 V Operation ... Needs Only An Unregulated Supply
• Open-Collector 25 mA Output ... Compatible with Digital Logic
• Reverse Battery Protection
• Activate with Small,Commercially Available Permanent Magnets
• Solid-State Reliability ... No Moving Parts
• Small Size
• Resistant to Physical Stress

Description

These Hall-effect switches are monolithic integrated circuits with tighter magnetic specifications, designed to operate continuously over extended temperatures to +150¡ãC, and are more stable with both temperature and supply voltage changes. The unipolar switching characteristic makes these devices ideal for use with a simple bar or rod magnet. The three basic devices (3121, 3122, and 3123) are identical except for magnetic switch points.

Each device includes a voltage regulator for operation with supply voltages of 4.5 volts to 24 volts, reverse battery protection diode, quadratic Hall-voltage generator, temperature compensation circuitry, small-signal amplifier, Schmitt trigger, and an open-collector output to sink up to 25 mA. With suitable output pull up, they can be used with bipolar or CMOS logic circuits. The 3121 is an improved replacement for the 3113 and 3119.

Functional Block Diagram