Allegro MicroSystems A1308LLHLX-3-T

Overview

A1308LLHLX-3-T from Allegro MicroSystems is a ratiometric linear Hall-effect sensor IC in a 3-pin SOT-23W surface-mount package, delivering 3.125 mV/G sensitivity, ±1.5% linearity error, and quiescent output voltage of 2.5 V at 5 V supply. It operates across –40°C to 150°C, features programmable temperature coefficients for QVO and sensitivity, and is AEC-Q100 qualified for automotive position sensing.

For engineers reviewing the A1308LLHLX-3-T datasheet, A1308LLHLX-3-T pinout, A1308LLHLX-3-T application, or A1308LLHLX-3-T equivalent, this device supports high-accuracy displacement and angular position measurement in constrained PCB layouts requiring stable analog output, low-noise performance, and robust thermal drift compensation.

Technical Context

The A1308LLHLX-3-T integrates a BiCMOS monolithic circuit with a Hall element, dynamic offset cancellation via high-speed chopping (400 kHz), and temperature-compensating circuitry that reduces intrinsic Hall-element drift. Its ratiometric architecture ensures output voltage, sensitivity, and clamp thresholds scale proportionally with VCC.

End-of-line programming sets both QVO and sensitivity temperature coefficients at 150°C, enabling sustained accuracy across the full –40°C to 150°C range. The device includes undervoltage lockout (UVLO), output clamps for short-circuit diagnostics, and a tuned low-pass filter for noise suppression.

Key Specifications

Pinout & Package

Package: 3-pin SOT-23W (2 mm × 3 mm × 1 mm), lead-free with 100% matte-tin plating, optimized for surface-mount assembly and thermal performance (R_θJA = 110°C/W on 2-layer PCB).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar linear Hall-effect sensor applications.

Compared with A1308LLHLX-5-T and A1309LLHLX-9-T, the A1308LLHLX-3-T offers optimal balance of sensitivity, noise, and thermal stability for mid-range displacement sensing-enabling direct interface with 12-bit ADCs while maintaining margin against saturation in typical automotive air-gap fields.

Availability

A1308LLHLX-3-T is available at Aetrix Electronics and suitable for automotive throttle position sensing, brake pedal monitoring, electric power steering rotor tracking, and industrial servo valve spool positioning requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for A1308LLHLX-3-T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Allegro MicroSystems is a U.S.-based semiconductor company specializing in magnetic sensing and power ICs, with design centers in North America and manufacturing partnerships globally.

The A1308 family was developed specifically for high-accuracy linear position sensing in automotive and industrial systems, emphasizing thermal stability, ratiometric precision, and AEC-Q100 compliance for safety-critical deployments.

FAQ

What is the operating temperature range of the A1308LLHLX-3-T?

The A1308LLHLX-3-T is rated for continuous operation from –40°C to +150°C, validated per AEC-Q100 Grade 0 requirements. This range applies specifically to the SOT-23W (LH) package variant and covers full electrical performance including sensitivity, QVO, and output clamping behavior without derating.

Does the A1308LLHLX-3-T require an external bypass capacitor?

Yes, the A1308LLHLX-3-T requires a 0.1 µF ceramic bypass capacitor between VCC and GND, placed as close as possible to the device pins. This capacitor stabilizes the internal regulator, ensures proper UVLO function, and suppresses high-frequency noise that could affect the 400 kHz chopping circuit's performance.

How does the A1308LLHLX-3-T achieve thermal stability of its quiescent output voltage?

The A1308LLHLX-3-T achieves QVO stability through end-of-line programming of its temperature coefficient at 150°C, combined with dynamic offset cancellation using a 400 kHz chopping scheme. This dual approach limits QVO drift to ≤±10 mV across –40°C to 150°C, as verified in production test data for the L-temp option.

Is the A1308LLHLX-3-T pin-compatible with other A1308 variants in the SOT-23W package?

Yes, all A1308LLHLX-x-T variants-including A1308LLHLX-05-T, -1-T, -2-T, -3-T, and -5-T-share identical 3-pin SOT-23W pinout (VCC, VOUT, GND), footprint, and thermal characteristics. Sensitivity and temperature coefficient are the only differing parameters; no PCB layout change is needed when substituting within this suffix group.

What diagnostic capability does the A1308LLHLX-3-T provide via its output clamps?

The A1308LLHLX-3-T provides short-circuit diagnostics through its ratiometric output clamps: V_CLPLOW (0.4–0.7 V) and V_CLPHIGH (4.35–4.65 V). When VOUT saturates at either limit under normal supply conditions, it indicates a wiring fault-enabling ECU-level fault detection without additional comparators or monitoring circuitry.