Allegro MicroSystems A1386LLHLT-T

Overview

A1386LLHLT-T from Allegro MicroSystems is a discontinued, field-programmable linear Hall effect sensor IC designed for automotive and industrial position sensing. It delivers ratiometric analog output (1.9–3.3 mV/G sensitivity at 5 V), operates from 2.7–5.5 V supply, supports dual modes (normal/low-power), and features factory-programmed 0.13%/°C sensitivity temperature coefficient. It targets high-accuracy rotary or linear motion detection in engine control, throttle position, and brake pedal sensing.

For engineers reviewing the A1386LLHLT-T datasheet, A1386LLHLT-T pinout, A1386LLHLT-T application, or A1386LLHLT-T equivalent, key selection considerations include its 3-pin SOT-23W package, end-of-line programmability of quiescent voltage (2.4–2.6 V) and sensitivity, ±1.5% linearity error in normal mode, –40°C to 150°C operating range, and discontinuation status requiring transition planning.

Technical Context

The A1386LLHLT-T integrates a BiCMOS monolithic circuit with Hall element, dynamic quadrature offset cancellation (200 kHz chopper frequency), temperature-compensated amplifier, and clamped low-impedance output stage. Its dual-mode operation uses supply voltage thresholds (3.7 V / 4.1 V) to switch between full-accuracy normal mode (6.4 mA ICC) and low-power mode (≤4 mA ICC) for wake-up detection under 3 V.

Programming occurs via voltage pulses applied to VOUT: mid-level (14–16 V) and high-level (26–28 V) pulses configure Try/Blow/Lock modes. Five-bit quiescent voltage trim (12–18 mV/step) and six-bit sensitivity trim (30–50 µV/G/step) enable end-of-line calibration without external components, while factory-set TCSENS compensates for NdFeB magnet drift.

Key Specifications

Pinout & Package

Package: 3-pin SOT-23W (2 mm × 3 mm × 1 mm), lead-free, matte tin plating, surface-mount.

Key Features

Applications

Equivalent & Alternatives

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

Compared with A1386LLHLT-T, A1389LUA-T offers drop-in compatibility in UA package with superior production longevity and tighter parametric tolerances, while TLV493D-A1B6 shifts to digital architecture-requiring PCB redesign but enabling advanced diagnostics and multi-axis capability.

Availability

A1386LLHLT-T is available at Aetrix Electronics and suitable for legacy automotive repair, industrial equipment maintenance, and obsolescence mitigation programs requiring stable component supply for existing designs.

Supply support for A1386LLHLT-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 designer and manufacturer of high-performance Hall-effect sensors and power ICs, specializing in magnetic sensing and precision power management solutions.

The A1386 product line was developed specifically for automotive and industrial position-sensing applications demanding high accuracy, wide temperature operation, and programmable calibration-enabling cost-effective, robust alternatives to potentiometers and resolvers.

FAQ

Is A1386LLHLT-T still in production?

No, A1386LLHLT-T is a discontinued product. Allegro MicroSystems ceased production as of December 1, 2015. It is not recommended for new designs. Aetrix Electronics maintains limited legacy stock for repair and maintenance of existing systems, but long-term supply cannot be guaranteed. Customers should plan migration to A1389LUA-T or other qualified alternatives when designing next-generation hardware.

What package type does A1386LLHLT-T use?

A1386LLHLT-T uses the 3-pin SOT-23W surface-mount package (2 mm × 3 mm × 1 mm), identified by the "LH" suffix. This miniature lead-free package features 100% matte tin leadframe plating and is optimized for automated reflow assembly in high-density automotive PCBs. Pin 1 is VCC, Pin 2 is GND, and Pin 3 is VOUT-matching the standard SOT-23 pinout orientation.

Can A1386LLHLT-T operate from a 3 V supply?

Yes, A1386LLHLT-T supports 3 V operation in low-power mode (2.8–3.2 V range), delivering reduced-accuracy magnetic detection suitable for wake-up or presence sensing. In this mode, supply current drops to ≤4 mA and linearity degrades to ±2%, but output remains functional for pole detection. For full-specification performance-including 1.9–3.3 mV/G sensitivity and ±1.5% linearity-the device requires ≥4.5 V supply in normal mode.

How is A1386LLHLT-T programmed?

A1386LLHLT-T is programmed via voltage pulses applied to the VOUT pin: mid-level (14–16 V) and high-level (26–28 V) pulses configure Try/Blow/Lock modes. Programming adjusts quiescent voltage (5-bit, 12–18 mV/step) and sensitivity (6-bit, 30–50 µV/G/step). A 0.1 µF capacitor must be placed between VOUT and GND during fuse blowing. The A1386LLHLT-T does not support I²C or SPI-programming is strictly analog pulse-based.

What is the maximum junction temperature of A1386LLHLT-T?

The maximum junction temperature (TJ(max)) of A1386LLHLT-T is 165°C. Thermal performance depends on PCB layout: with a 1-layer board and copper limited to solder pads, RθJA is 228°C/W; with a 2-layer board and thermal vias, it improves to 110°C/W. Derating curves in the datasheet show allowable VCC decreases above 125°C ambient-critical for under-hood placement where A1386LLHLT-T may experience sustained 150°C ambient temperatures.