component
A1121ELHLX-T
Public Made by Adomby adom
Allegro MicroSystems, LLC Hall Sensor, SOT-23. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
3D Model
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Symbol & Footprint
Schematic Symbol
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PCB Footprint
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Datasheet
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Contents
README
markdownA1121ELHLX-T
Allegro MicroSystems, LLC · Hall Sensor · SOT-23
A1121ELHLX-T from Allegro MicroSystems, LLC, in a SOT-23. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.
Pinout
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | VCC | power_in | Connects power supply to chip; operating range 3 to 24 V (absolute maximum 26.5 V forward, -30 V reverse), with a 0.1 µF bypass capacitor to GND recommended. |
| 2 | VOUT | output | Open-drain output from circuit that turns on (logic low) in a south-pole field above BOP for the A1121, sinking up to 25 mA continuous with a 26 V maximum off voltage. |
| 3 | GND | power_in | Ground connection for the device. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Allegro MicroSystems, LLC |
| Package | SOT-23 |
| Category | Sensors |
| Pins | 3 |
Electrical characteristics
Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).
| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Forward Supply Voltage (absolute max) | VCC | 26.5 | V | 3 | |||
| Reverse Supply Voltage | VRCC | -30 | V | 3 | |||
| Output Off Voltage | VOUT | 26 | V | 3 | |||
| Continuous Output Current | IOUT | 25 | mA | 3 | |||
| Reverse Output Current | IROUT | -50 | mA | 3 | |||
| Operating Ambient Temperature, Range E | TA | -40 | 85 | °C | Range E | 3 | |
| Maximum Junction Temperature | TJ(max) | 165 | °C | 3 | |||
| Storage Temperature | Tstg | -65 | 170 | °C | 3 | ||
| Forward Supply Voltage (operating) | VCC | 3 | 24 | V | Operating, TJ < 165°C | 4 | |
| Output Leakage Current | IOUTOFF | 10 | µA | VOUT = 24 V, B < BRP | 4 | ||
| Output Saturation Voltage | VOUT(SAT) | 185 | 500 | mV | IOUT = 20 mA, B > BOP | 4 | |
| Output Current Limit | IOM | 30 | 60 | mA | B > BOP | 4 | |
| Power-On Time | tPO | 25 | µs | VCC > 3.0 V, B < BRP(min), 10 G, B > BOP(max) + 10 G | 4 | ||
| Chopping Frequency | fC | 800 | kHz | 4 | |||
| Output Rise Time | tr | 0.2 | 2 | µs | RL = 820 Ω, CS = 20 pF | 4 | |
| Output Fall Time | tf | 0.1 | 2 | µs | RL = 820 Ω, CS = 20 pF | 4 | |
| Supply Current (On) | ICC(ON) | 4 | mA | VCC = 12 V, B > BOP | 4 | ||
| Supply Current (Off) | ICC(OFF) | 4 | mA | VCC = 12 V, B < BRP | 4 | ||
| Reverse Supply Current | IRCC | -5 | mA | VRCC = -30 V | 4 | ||
| Supply Zener Clamp Voltage | VZ | 28 | V | ICC = 5 mA; TA = 25°C | 4 | ||
| Zener Impedance | IZ | 50 | Ω | ICC = 5 mA; TA = 25°C | 4 | ||
| Operate Point | BOP | 50 | 95 | 135 | G | A1121 | 5 |
| Release Point | BRP | 40 | 70 | 110 | G | A1121 | 5 |
| Hysteresis | BHYS | 10 | 25 | 42 | G | A1121, BOP, BRP | 5 |
| Package Thermal Resistance, LH 1-layer PCB | RθJA | 228 | °C/W | Package LH, 1-layer PCB with copper limited to solder pads | 6 | ||
| Package Thermal Resistance, LH 2-layer PCB | RθJA | 110 | °C/W | Package LH, 2-layer PCB with 0.463 in.2 of copper area each side connected by thermal vias | 6 |
Materials and finish
As the datasheet states them (page.json metadata.appearance; the 3D model's colours follow it).
| Part | Material | Colour / plating | Datasheet says | Page |
|---|---|---|---|---|
| contacts | tin | SIP for through-hole mounting. Each package type is lead (Pb) free (suffix, -T), with a 100% matte-tin-plated leadframe. | 1 |
CAD (KiCad official)
- Symbol:
A1121ELHLX-T - Footprint:
Package_TO_SOT_SMD:SOT-23 - 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files:
a1121elhlx-t-etched.step/a1121elhlx-t-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);a1121elhlx-t.step/a1121elhlx-t.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Allegro MicroSystems, LLC datasheet (18 pp, sha256
708f85ed25b42178, retrieved 2026-10-26, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-sonnet-5-5(text), consensusclaude-sonnet-5-5(agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish. - CAD: KiCad official libraries (CC-BY-SA 4.0).