Allegro MicroSystems A1309KUA-9-T

Overview

A1309KUA-9-T from Allegro MicroSystems is a ratiometric linear Hall-effect sensor IC with analog voltage output, designed for high-accuracy angular and displacement sensing in automotive and industrial systems. It delivers 9 mV/G sensitivity, operates from –40°C to 125°C, features programmable QVO temperature coefficient, and uses dynamic offset cancellation for stable quiescent output (2.5 V at 5 V supply) across temperature and supply variation.

For engineers reviewing the A1309KUA-9-T datasheet, A1309KUA-9-T pinout, A1309KUA-9-T application, or A1309KUA-9-T equivalent, this device supports precision position feedback in throttle valves, pedal sensors, and rotary actuators where low-drift analog linearity and AEC-Q100 qualification are required.

Technical Context

The A1309KUA-9-T integrates a BiCMOS monolithic circuit with Hall element, high-gain amplifier, tuned filter, and proprietary dynamic offset cancellation. Its chopper-stabilized architecture operates at 400 kHz to suppress thermal and mechanical stress-induced drift, enabling precise recoverability after temperature cycling.

It implements ratiometric operation-QVO, sensitivity, and output clamps scale with VCC-and includes undervoltage lockout (UVLO) with 2.5 V turn-off and 3 V turn-on thresholds, plus output voltage 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), through-hole mounting, 1.5 mm × 4 mm × 3 mm, 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 A1309KUA-9-T, the A1309LLHLX-9-T offers identical analog performance in a smaller SMT footprint and higher temperature grade, while the TLV493D-A1B6 trades analog simplicity for digital flexibility and 3D capability-neither is pin-compatible, but both serve distinct design priorities in position sensing.

Availability

A1309KUA-9-T is available at Aetrix Electronics and suitable for automotive throttle control, brake pedal sensing, and industrial valve actuation requiring stable component supply, AEC-Q100 compliance, and through-hole mounting robustness.

Supply support for A1309KUA-9-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, power ICs, and motor driver solutions for automotive and industrial markets.

The A1309KUA-9-T belongs to Allegro's linear Hall-effect sensor family, engineered for high-accuracy analog position feedback in safety-critical motion control systems where drift, noise, and environmental resilience are paramount.

FAQ

What is the operating temperature range for the A1309KUA-9-T?

The A1309KUA-9-T operates from –40°C to +125°C, matching the "K" temperature option defined in Allegro's selection guide. This range is validated per AEC-Q100 Grade 0 requirements and supports under-hood automotive use cases such as throttle and pedal sensing where ambient heat exposure is significant. The device maintains specified sensitivity and QVO accuracy across this full span due to end-of-line programming of temperature coefficients.

Does the A1309KUA-9-T require an external bypass capacitor?

Yes, the A1309KUA-9-T requires a minimum 0.1 µF ceramic bypass capacitor between VCC and GND, placed as close as possible to the package pins. This capacitor stabilizes the internal regulator, suppresses supply noise, and ensures proper operation of the chopper-stabilized analog front-end. Omission or improper placement degrades noise performance and may cause instability in the output voltage, especially under fast magnetic transients.

How does the A1309KUA-9-T implement undervoltage lockout (UVLO)?

The A1309KUA-9-T incorporates integrated UVLO with asymmetric thresholds: it powers on when VCC rises above 3 V and powers off when VCC falls below 2.5 V. This hysteresis prevents output oscillation near the threshold and ensures clean state transitions. During UVLO, VOUT is actively pulled low to GND-providing a known fault state that supports diagnostic logic in host controllers interfacing with the A1309KUA-9-T.

Can the A1309KUA-9-T be used in reverse-polarity magnetic field detection?

No-the A1309KUA-9-T has forward-polarity output only, meaning its voltage increases with south-pole field strength and decreases with north-pole field strength. For true bipolar (reverse-polarity) operation, Allegro offers the A1309LLHLX-RP9-T variant, which provides –9 mV/G sensitivity. The A1309KUA-9-T's output remains within its 0.4–4.65 V clamped range for valid field inputs but does not invert polarity relative to field direction.

What is the purpose of the output voltage clamps in the A1309KUA-9-T?

The A1309KUA-9-T features active output clamps: VCLPLOW (0.40–0.70 V) and VCLPHIGH (4.35–4.65 V) referenced to VCC. These clamps limit the analog output swing during over-field conditions or wiring faults, allowing downstream circuitry to detect open-load, short-to-ground, or short-to-VCC events. Because the clamps scale ratiometrically with VCC, they maintain diagnostic integrity across supply variations-a key requirement for functional safety in automotive applications using the A1309KUA-9-T.