Chopper-Stabilized Precision Hall-Effect Switches

A1120, A1121, A1122, A1123, A1125

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The A1120, A1121, A1122, A1123, and A1125 Hall-effect, unipolar switches 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 dynamic offset cancellation, which reduces the residual offset voltage normally caused by device overmolding, temperature dependencies, and thermal stress.

Each device includes on a single silicon chip a voltage regulator, Hall-voltage generator, small-signal amplifier, chopper stabilization, Schmitt trigger, and a short-circuit protected open-drain output to sink up to 25 mA.

An on-board regulator permits operation with supply voltages of 3 to 24 V. The advantage of operating down to 3 V is that the device can be used in 3 V applications or with additional external resistance in series with the supply pin for greater protection against high voltage transient events.

For the A1120, A1121, A1122, and A1123, a south pole of sufficient strength turns the output on. Removal of the magnetic field turns the output off. The A1125 is complementary, in that for these devices, a south pole turns the A1125 output off, and removal of the magnetic field turns the output on.

Two package styles provide a magnetically optimized package for most applications. Package type LH is a modified SOT23W, surface mount package, while UA is a three-lead ultra-mini SIP for through-hole mounting. Each package type is lead (Pb) free (suffix, –T), with a 100% matte tin plated leadframe.

Allegro MicroSystems recommends the APS11200 for new Automotive 3-wire Hall-Effect switch IC designs.

  • AEC-Q100 automotive qualified 
  • Unipolar switchpoints
  • Resistant to physical stress
  • Superior temperature stability
  • Output short-circuit protection
  • Operation from unregulated supply
  • Reverse-battery protection
  • Solid-state reliability
  • Small package sizes

Package type LH is a modified SOT23W, surface mount package, while UA is a three-lead ultra-mini SIP for through-hole mounting. Each package type is lead (Pb) free (suffix, –T), with a 100% matte tin plated leadframe.

3-pin SOT23W (suffix LH)

LH Package Documentation

 

3-pin SIP, matrix HD style (suffix UA)

3-pin SIP, chopper style (suffix UA)

UA Package Documentation

Part Number Specifications and Availability