Allegro MicroSystems A1308KUA-3-T

Overview

A1308KUA-3-T from Allegro MicroSystems is a ratiometric linear Hall-effect sensor IC designed for high-accuracy angular and displacement sensing in constrained spaces. It delivers 3.125 mV/G sensitivity, ±1.5% linearity error, and temperature-stable quiescent output (2.5 V at 5 V supply) across –40°C to 125°C. Its 3-pin ultramini SIP through-hole package enables robust mounting in automotive throttle position and industrial rotary encoder applications.

For engineers reviewing the A1308KUA-3-T datasheet, A1308KUA-3-T pinout, A1308KUA-3-T application, or A1308KUA-3-T equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, application-specific implementation guidance, and two confirmed alternative parts with documented functional and thermal differences.

Technical Context

The A1308KUA-3-T integrates a BiCMOS monolithic circuit with Hall element, dynamic offset cancellation, and temperature-compensated amplifier stages. Its proprietary chopping scheme operates at 400 kHz to suppress thermal drift and mechanical stress effects on quiescent voltage output (QVO).

End-of-line programming sets both QVO and sensitivity temperature coefficients (0.12%/°C typical) at 125°C for K-temp devices, ensuring stable analog output across full operating range. The device features undervoltage lockout (2.5 V turn-off, 3 V turn-on), 20 kHz internal bandwidth, and output clamps (0.4–0.7 V low, 4.35–4.65 V high) for short-circuit diagnostics.

Key Specifications

Pinout & Package

Package: 3-pin ultramini SIP (UA), 1.5 mm × 4 mm × 3 mm, through-hole mount, lead-free with 100% matte-tin plating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with A1308KUA-3-T, A1308KUATN-3-T offers identical electrical performance with packaging suited for volume SMT, while TLV493D-A1B6 trades analog immediacy and integrated protection for digital flexibility and tri-axis capability - making it unsuitable as a drop-in replacement but viable for new designs prioritizing bus efficiency over analog robustness.

Availability

A1308KUA-3-T is available at Aetrix Electronics and suitable for automotive throttle position sensing, industrial rotary encoder feedback, electric power steering torque sensing, and appliance motor commutation requiring stable component supply and AEC-Q100-qualified performance.

Supply support for A1308KUA-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 designer and manufacturer of high-performance magnetic sensing and power IC solutions, founded in 1989 and headquartered in Manchester, NH.

The A1308 family was developed specifically for high-accuracy, temperature-stable linear position sensing in automotive and industrial systems where analog output, robust EMC performance, and mechanical stress immunity are critical.

FAQ

What is the operating temperature range of the A1308KUA-3-T?

The A1308KUA-3-T is rated for –40°C to +125°C ambient operation, matching the "K" temperature option defined in Allegro's selection guide. This range is validated for automotive under-hood applications and industrial motor control environments where thermal cycling and long-term stability are critical. The device achieves this via end-of-line programming of sensitivity and QVO temperature coefficients at 125°C.

Does the A1308KUA-3-T require an external bypass capacitor?

Yes, the A1308KUA-3-T requires a 0.1 µF ceramic bypass capacitor between VCC (Pin 1) and GND (Pin 2). This capacitor stabilizes the internal regulator, ensures clean UVLO behavior, and suppresses high-frequency noise that could degrade output signal integrity. Allegro specifies CBYPASS = 0.1 µF in all electrical characteristics tables and recommends placement within 2 mm of the pins.

How does the A1308KUA-3-T achieve its high linearity and low drift?

The A1308KUA-3-T achieves ±1.5% linearity and ±10 mV QVO drift via three integrated techniques: (1) factory end-of-line optimization of sensitivity and QVO, (2) proprietary 400 kHz chopping architecture that separates magnetic signal from thermal offset in frequency domain, and (3) BiCMOS process enabling low-noise amplification and dynamic offset cancellation. These are confirmed in the Functional Block Diagram and DRIFT CHARACTERISTICS table.

Can the A1308KUA-3-T be used in safety-critical automotive systems?

Yes - the A1308KUA-3-T is AEC-Q100 qualified (Grade 0), meaning it meets stress test requirements for automotive powertrain and chassis applications up to +150°C junction temperature. Its output voltage clamps, undervoltage lockout, and precise recoverability after temperature cycling support functional safety architectures. However, system-level ASIL compliance requires additional hardware/software validation beyond the component qualification.

What is the purpose of the output voltage clamps in the A1308KUA-3-T?

The A1308KUA-3-T features hard output clamps at 0.55 V (low) and 4.5 V (high) to provide intrinsic short-circuit and overvoltage fault detection. When VOUT is forced below 0.55 V or above 4.5 V - indicating wiring faults, load shorts, or ESD events - the clamps limit current and generate a repeatable diagnostic signature. This eliminates need for external protection circuitry in many automotive and industrial designs.