Allegro MicroSystems A1388LLHLT-2-T

Overview

A1388LLHLT-2-T from Allegro MicroSystems is a ratiometric linear Hall-effect sensor IC designed for high-accuracy angular and displacement sensing in constrained PCB spaces. It delivers 2.5 mV/G sensitivity, ±1.5% linearity error, and temperature-stable quiescent output (2.5 V at 5 V supply) across –40°C to 150°C, enabling precise position feedback in automotive throttle and industrial valve control systems.

For engineers reviewing the A1388LLHLT-2-T datasheet, A1388LLHLT-2-T pinout, A1388LLHLT-2-T application, or A1388LLHLT-2-T equivalent, key selection criteria include its SOT-23W package footprint, 20 kHz bandwidth, chopper-stabilized offset drift < ±20 mV over temperature, and integrated undervoltage lockout with 2.5 V turn-off threshold.

Technical Context

The A1388LLHLT-2-T integrates a BiCMOS monolithic circuit with a Hall element, dynamic offset cancellation, and temperature-compensating circuitry programmed at end-of-line to stabilize both sensitivity (TC_Sens = 0.12%/°C typ) and quiescent voltage output (QVO) across –40°C to 150°C. Its high-speed chopping scheme operates at 400 kHz to suppress thermal and mechanical stress-induced drift.

This device implements ratiometric operation: QVO, sensitivity, and output clamps scale linearly with V_CC, ensuring consistent performance under supply variation. Output voltage clamps (0.4–0.7 V low, 4.35–4.65 V high) provide short-circuit diagnostics while maintaining analog linearity within ±400 G magnetic range.

Key Specifications

Pinout & Package

Package: 3-pin SOT-23W surface-mount package (2 mm × 3 mm × 1 mm), lead-free with 100% matte-tin plating, optimized for high-density automotive PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with A1388LLHLT-2-T, A1388LLHLX-2-T offers identical electrical performance with different packaging logistics, while TLV493D-A1B6 shifts to digital architecture-requiring firmware support and sacrificing analog immediacy and fault-clamp diagnostics.

Availability

A1388LLHLT-2-T is available at Aetrix Electronics and suitable for automotive throttle control, industrial actuator feedback, and electric power steering systems requiring stable component supply across extended temperature ranges and high-reliability production cycles.

Supply support for A1388LLHLT-2-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 decades of automotive-grade reliability validation and AEC-Q100 qualification expertise.

The A1388 family targets high-accuracy linear position sensing in harsh environments, emphasizing temperature stability, mechanical stress immunity, and diagnostic capability for safety-critical motion control.

FAQ

What is the operating temperature range of the A1388LLHLT-2-T?

The A1388LLHLT-2-T operates from –40°C to +150°C ambient temperature, validated across this full range for quiescent output stability, sensitivity accuracy, and functional integrity. Its end-of-line programming compensates for thermal drift, ensuring ≤ ±20 mV QVO shift and ≤ ±2% sensitivity hysteresis after temperature cycling - critical for under-hood automotive use where the A1388LLHLT-2-T is commonly deployed.

Does the A1388LLHLT-2-T require an external bypass capacitor?

Yes, the A1388LLHLT-2-T requires a 0.1 µF ceramic capacitor between VCC and GND, placed as close as possible to the device pins. This capacitor stabilizes the internal regulator, suppresses supply noise, and ensures proper operation of the chopper-stabilized amplifier. Omitting it risks increased output noise, UVLO instability, and degraded linearity - all confirmed in Allegro's application notes and electrical characterization data for the A1388LLHLT-2-T.

How does the A1388LLHLT-2-T achieve its high accuracy over temperature?

The A1388LLHLT-2-T achieves high accuracy via end-of-line programming of non-volatile memory that stores optimized coefficients for both sensitivity temperature coefficient (TC_Sens = 0.12%/°C typ) and QVO drift compensation. Combined with a proprietary high-frequency chopping scheme (400 kHz), this actively cancels thermal and mechanical offset drift - resulting in < ±20 mV QVO shift and ±2% sensitivity hysteresis over –40°C to 150°C, as measured and specified for the A1388LLHLT-2-T.

What is the purpose of the output voltage clamps in the A1388LLHLT-2-T?

The A1388LLHLT-2-T features output voltage clamps (V_CLPLOW = 0.4–0.7 V, V_CLPHIGH = 4.35–4.65 V at 5 V supply) to provide short-circuit and open-load diagnostics. When VOUT is forced outside these bounds - e.g., by wiring faults or ESD events - the clamps limit excursion while preserving analog linearity within the valid magnetic range (±400 G). This eliminates need for external protection circuitry and enables fault detection in real time, a documented feature of the A1388LLHLT-2-T.

Is the A1388LLHLT-2-T pin-compatible with other Allegro Hall sensors?

No, the A1388LLHLT-2-T is not pin-compatible with other Allegro Hall-effect sensors such as the A132x or A130x families. Its 3-pin SOT-23W layout (VCC–VOUT–GND) and internal architecture - including chopper stabilization, ratiometric clamps, and end-of-line programming - are specific to the A1388/A1389 family. Substitution requires verification of pin function mapping, electrical interface, and thermal derating - especially since the A1388LLHLT-2-T's thermal resistance (R_θJA = 110°C/W on 2-layer PCB) differs from legacy packages.