Allegro MicroSystems A31004KLHALT-RP3-0TC

Overview

A31004KLHALT-RP3-0TC from Allegro MicroSystems is a unidirectional linear Hall-effect sensor IC with ratiometric analog voltage output, optimized for north-pole magnetic field detection. It delivers 3.3 mV/G sensitivity, 0.5 V quiescent output (QVO), and 0%/°C typical sensitivity temperature coefficient across –40°C to 125°C. Designed for high-accuracy angular position and displacement sensing in automotive throttle and pedal modules.

For engineers reviewing the A31004KLHALT-RP3-0TC datasheet, A31004KLHALT-RP3-0TC pinout, A31004KLHALT-RP3-0TC application, or A31004KLHALT-RP3-0TC equivalent, key selection criteria include its programmed zero-TC sensitivity, SOT-23W package footprint, chopper-stabilized offset drift performance, and integrated undervoltage lockout with diagnostic clamping.

Technical Context

The A31004KLHALT-RP3-0TC integrates a BiCMOS monolithic circuit featuring a Hall element, dynamic offset cancellation, temperature-compensating circuitry, and a clamped low-impedance output stage. Its proprietary chopping scheme operates at 400 kHz to suppress thermal and mechanical stress-induced QVO drift.

End-of-line programming sets both sensitivity and QVO temperature coefficients - specifically tuned to achieve 0%/°C typical TCSens over –40°C to 125°C. The device implements ratiometric operation: QVO, sensitivity, and output clamps all scale linearly with VCC, enabling robust performance under supply variation.

Key Specifications

Pinout & Package

Package: LH - 3-pin SOT-23W surface-mount package (2.0 mm × 3.0 mm × 1.0 mm), lead-free with 100% matte-tin plating, optimized for space-constrained PCB layouts and automated assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with A31004LLHALX, the A31004KLHALT-RP3-0TC trades extended temperature rating for significantly tighter sensitivity TC (0% vs. 0.12%/°C), making it preferable for precision analog feedback loops. Against MLX90393, it avoids digital overhead and calibration complexity but lacks multi-axis or programmable features.

Availability

A31004KLHALT-RP3-0TC is available at Aetrix Electronics and suitable for automotive throttle position sensing, industrial motor commutation, brake pedal displacement monitoring, and electric power steering torque sensing requiring stable component supply across production lifecycles.

Supply support for A31004KLHALT-RP3-0TC 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 high-performance magnetic sensing and power ICs, with design centers in North America and manufacturing partnerships globally.

The A31004 product line targets high-accuracy, high-reliability position and displacement sensing in automotive and industrial environments - emphasizing end-of-line programmability, thermal stability, and robust EMC performance.

FAQ

What is the magnetic polarity sensitivity of the A31004KLHALT-RP3-0TC?

The A31004KLHALT-RP3-0TC is north-active: it increases its output voltage in response to a north-pole magnetic field applied perpendicular to the branded surface of the package. This polarity is confirmed in the Selection Guide and functional block diagram of the official datasheet. The device does not respond to south-pole fields in standard operation, and its sensitivity specification (3.3 mV/G) applies exclusively to north-pole excitation.

Does the A31004KLHALT-RP3-0TC require external calibration for temperature drift?

No, the A31004KLHALT-RP3-0TC does not require external calibration for temperature drift. Its sensitivity temperature coefficient is factory-programmed to 0%/°C typical across –40°C to 125°C using Allegro's end-of-line test process. This eliminates the need for software-based temperature compensation in host systems, simplifying firmware development and improving long-term accuracy stability.

What is the purpose of the output voltage clamps in the A31004KLHALT-RP3-0TC?

The A31004KLHALT-RP3-0TC features output voltage clamps at 2.97 V (high) and 0.34 V (low) to enable hardware-level short-circuit diagnostics. When VOUT is forced beyond these limits - e.g., due to wiring faults or load shorts - the clamps activate and hold the output at predictable levels, allowing the host system to detect failure without additional discrete components. These clamps scale ratiometrically with VCC.

Can the A31004KLHALT-RP3-0TC operate from a 5 V supply?

No, the A31004KLHALT-RP3-0TC is specified only for 3.0–3.63 V operation. Absolute maximum forward supply voltage is 8 V, but functional operation outside the 3.0–3.63 V range is not guaranteed. Supplying 5 V risks violating internal biasing and may cause incorrect UVLO behavior, inaccurate sensitivity scaling, or accelerated parametric shift. A dedicated 3.3 V LDO regulator is required.

How does the chopper stabilization technique improve performance in the A31004KLHALT-RP3-0TC?

The A31004KLHALT-RP3-0TC uses a 400 kHz chopper stabilization technique to separate magnetic signal from DC offset in the frequency domain. This reduces QVO drift to ±20 mV over –40°C to 125°C and enables precise recoverability after thermal cycling - critical for automotive applications where repeated temperature excursions occur. The technique also lowers input-referred noise to 1.89 mG/√Hz.