Allegro MicroSystems ALS31000LLHALT

Overview

ALS31000LLHALT from Allegro MicroSystems is a unidirectional linear Hall-effect sensor IC in a 3-pin SOT-23W package, delivering ratiometric analog output voltage proportional to applied magnetic field. It features 2.4 mV/G sensitivity, 0.7 V quiescent output (QVO), and operates from 4.5–5.5 V supply across –40°C to 150°C - enabling high-accuracy angular and displacement sensing in automotive throttle and industrial valve position feedback systems.

For engineers reviewing the ALS31000LLHALT datasheet, ALS31000LLHALT pinout, ALS31000LLHALT application, or ALS31000LLHALT equivalent, this page provides verified technical context, validated pin functions, temperature-stable performance metrics, and real-world application constraints for precision magnetic sensing designs.

Technical Context

The ALS31000LLHALT integrates a BiCMOS monolithic circuit with dynamic offset cancellation, high-speed chopping at 400 kHz, and programmable temperature coefficients for both sensitivity (0.12 %/°C typ) and QVO - all calibrated during Allegro's end-of-line test to sustain accuracy across –40°C to 150°C. Its clamped low-impedance output stage enables short-circuit diagnostics via VCLPHIGH (4.5 V) and VCLPLOW (0.51 V) thresholds.

It implements ratiometric operation: QVO, sensitivity, and clamp voltages scale linearly with VCC, ensuring stable performance under supply variation. The device includes undervoltage lockout (UVLO) with 3 V turn-on and 2.5 V turn-off thresholds, plus 50 µs power-on time and 30 µs delay-to-clamp response for fast transient handling in safety-critical motion control loops.

Key Specifications

Pinout & Package

Package: 3-pin SOT-23W (LH), 2.0 mm × 3.0 mm × 1.0 mm, lead-free with matte-tin plating, surface-mount compatible.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MLX90393ELD-ABA-000-TU and A1324LLHLT-T, the ALS31000LLHALT uniquely combines end-of-line TC programming, ratiometric clamping, and 20 kHz bandwidth in a miniature package - making it the only option that delivers automotive-grade accuracy without external calibration or digital interface overhead.

Availability

ALS31000LLHALT is available at Aetrix Electronics and suitable for automotive throttle control, industrial actuator feedback, electric power steering, HVAC damper positioning, and precision linear displacement sensing requiring stable component supply across extended temperature ranges.

Supply support for ALS31000LLHALT 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 for automotive and industrial markets.

The ALS31000 product line targets high-accuracy, high-reliability linear Hall sensing in harsh environments - designed specifically for displacement, angular position, and current sensing where end-of-line optimization and temperature stability are mandatory.

FAQ

What is the operating supply voltage range for the ALS31000LLHALT?

The ALS31000LLHALT operates from 4.5 V to 5.5 V, with undervoltage lockout engaging below 2.5 V (turn-off) and above 3 V (turn-on). This 4.5–5.5 V range ensures compatibility with standard 5 V automotive and industrial power rails while maintaining ratiometric accuracy across the full span. The ALS31000LLHALT draws 9–11.5 mA typical supply current under no-load conditions.

How does the ALS31000LLHALT achieve temperature-stable sensitivity and QVO?

The ALS31000LLHALT achieves temperature stability through end-of-line programming of both sensitivity temperature coefficient (0.08–0.16 %/°C) and QVO temperature coefficient at Allegro's test facility. These coefficients are stored in on-chip non-volatile memory and applied dynamically across –40°C to 150°C, reducing QVO drift to ±10 mV and sustaining 2.4 mV/G sensitivity within ±2% over temperature. The ALS31000LLHALT uses dynamic offset cancellation and high-speed chopping to suppress thermal and mechanical stress effects.

What is the function of the output voltage clamps in the ALS31000LLHALT?

The ALS31000LLHALT features output voltage clamps at VCLPHIGH = 4.5 V and VCLPLOW = 0.51 V (at 25°C, VCC = 5 V), which scale ratiometrically with supply voltage. These clamps serve dual purposes: they define the usable magnetic field range (BMAX(+) ≈ 1560 G, BMAX(–) ≈ −1200 G), and enable short-circuit diagnostics - e.g., VOUT stuck at 0.51 V indicates short-to-VCC, while 4.5 V indicates short-to-GND. The ALS31000LLHALT's delay-to-clamp is 30 µs.

Is the ALS31000LLHALT pin-compatible with other Allegro Hall sensors in SOT-23W packages?

The ALS31000LLHALT uses the standard 3-pin SOT-23W (LH) footprint with VCC–VOUT–GND pinout, matching physical layout with Allegro A132x and A130x series devices. However, electrical behavior differs significantly: ALS31000LLHALT has 0.7 V QVO, 2.4 mV/G sensitivity, and end-of-line TC programming, whereas A1324LLHLT-T has 2.5 V QVO and 5 mV/G. Direct replacement requires validation of signal range, thermal drift, and diagnostic capability - the ALS31000LLHALT is not a drop-in substitute without system-level requalification.

What PCB layout considerations are critical for optimal ALS31000LLHALT performance?

For optimal ALS31000LLHALT performance, place a 0.1 µF ceramic bypass capacitor between VCC and GND as close as possible to the device pins. Use minimum 0.20 mm spacing between pads, avoid copper pours under the package, and route VOUT away from noisy traces. Thermal vias under the exposed pad (if present) improve RθJA from 228 °C/W to 110 °C/W. The ALS31000LLHALT's active area depth is 0.28 ±0.04 mm - magnet placement must align to branded face per datasheet mechanical drawing.