A1120, A1121, A1122, and A1125 Chopper Stabilized Precision Hall Effect Switches Features and Benefits Description Unipolar switchpoints The A1120, A1121, A1122, and A1125 Hall-effect, unipolar Resistant to physical stress switches are extremely temperature-stable and stress-resistant Superior temperature stability sensor ICs, especially suited for operation over extended Output short-circuit protection temperature ranges to 150C. Superior high-temperature Operation from unregulated supply performance is made possible through dynamic offset Reverse battery protection cancellation, which reduces the residual offset voltage normally Solid-state reliability caused by device overmolding, temperature dependencies, and Small package sizes 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. Packages: 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, and A1122 a south pole of sufficient strength turns the output on. Removal of the magnetic field 3-pin SOT23W (suffix LH) 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. 3-pin SIP (suffix UA) Not to scale 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. Functional Block Diagram VCC Regulator To All Subcircuits VOUT Low-Pass Filter Amp Control Current Limit GND A1120-DS, Rev. 14 Dynamic Offset Cancellation Sample and HoldA1120, A1121, A1122 Chopper Stabilized Precision Hall Effect Switches and A1125 Selection Guide Switchpoints Output In South (Positive) 1 (Typ.) Part Number Packing Mounting Ambient, T A Magnetic Field B B OP RP A1120ELHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount 2 A1120ELHLT-T 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount 40C to 85C A1120EUA-T Bulk, 500 pieces/bag 3-pin SIP through hole 35 25 A1120LLHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount 2 A1120LLHLT-T 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount 40C to 150C A1120LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole A1121ELHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount 2 A1121ELHLT-T 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount 40C to 85C A1121EUA-T Bulk, 500 pieces/bag 3-pin SIP through hole 95 70 On (logic low) A1121LLHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount 2 A1121LLHLT-T 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount 40C to 150C A1121LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole A1122ELHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount 2 A1122ELHLT-T 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount 40C to 85C A1122EUA-T Bulk, 500 pieces/bag 3-pin SIP through hole 150 125 A1122LLHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount 2 A1122LLHLT-T 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount 40C to 150C A1122LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole A1125ELHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount 2 A1125ELHLT-T 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount 40C to 85C A1125EUA-T Bulk, 500 pieces/bag 3-pin SIP through hole 35 25 Off (logic high) A1125LLHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount 2 A1125LLHLT-T 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount 40C to 150C A1125LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole 1 Contact Allegro for additional packing options. 2 Available through authorized Allegro distributors only. Allegro MicroSystems, LLC 2 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000 www.allegromicro.com