Diodes Incorporated AH3281Q-P-B

Overview

AH3281Q-P-B from Diodes Incorporated is an AEC-Q100 qualified, two-wire automotive Hall-effect latch switch IC in SIP-3 package, designed for position sensing in seatbelt buckles and gear position detection. It operates from 2.7V to 27V, features BOP = 8–28 G and BRP = –28 to –8 G at +25°C, includes integrated self-diagnostics, thermal shutdown at 190°C, and delivers 6 mA off-state supply current (IOFF(1)).

For engineers reviewing the AH3281Q-P-B datasheet, AH3281Q-P-B pinout, AH3281Q-P-B application, or AH3281Q-P-B equivalent, this page provides verified magnetic thresholds, latch behavior confirmation, thermal protection timing, supply current specs across temperature, and SIP-3 terminal mapping - all critical for automotive proximity sensing design validation.

Technical Context

The AH3281Q-P-B implements a chopper-stabilized architecture with dynamic offset cancellation to minimize switch point drift over temperature. Its latch functionality requires magnetic polarity reversal (south-to-north transition) to release output, ensuring stable state retention in rotating or oscillating mechanical systems.

Internal bandgap regulation supplies temperature-compensated biasing for sensing circuitry, while built-in reverse-blocking diode and zener clamp protect against battery polarity reversal and transient spikes up to ±32 V. UVLO activates below 2.2 V to prevent erratic operation during cold-crank conditions.

Key Specifications

Pinout & Package

Package: SIP-3 (Bulk Pack), 3-pin single-inline package with straight leads, footprint compatible with standard through-hole PCB mounting and wave soldering.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Hall latch switch applications.

Compared with AH3281Q-P-B, AL3281Q-P-B omits automotive qualification and diagnostics but offers identical electrical behavior for cost-sensitive non-automotive use, while TLE4961-2M trades two-wire simplicity for higher field immunity and external protection flexibility.

Availability

AH3281Q-P-B is available at Aetrix Electronics and suitable for seatbelt buckle detection, gear position sensing, and door/trunk closure monitoring requiring stable component supply across automotive production lifecycles.

Supply support for AH3281Q-P-B 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability components for automotive, industrial, and computing markets.

The AH32xxQ series belongs to Diodes' automotive Hall-effect sensor product line, engineered specifically for robust two-wire position sensing in harsh environments with integrated diagnostics and AEC-Q100 compliance.

FAQ

What is the magnetic polarity requirement for AH3281Q-P-B actuation?

The AH3281Q-P-B is a south-pole active latch: output turns ON when south pole flux exceeds BOP (8–28 G), and remains ON until north pole flux falls below BRP (−28 to −8 G). This polarity-specific behavior is confirmed in DS41822 Rev. 6, Table 1, and requires magnet orientation matching the part marking surface.

Does AH3281Q-P-B require an external bypass capacitor?

Yes - a minimum 100 nF ceramic capacitor must be placed between VDD and GND, located as close as possible to the IC pins. This is mandatory for power stabilization and noise immunity, as specified in DS41822 Rev. 6, Note 4, and omission causes erratic switching or failure to meet tD ≤ 7 μs response time.

How does the thermal protection behave during sustained overload?

When junction temperature reaches 190°C, the device shuts down output and reduces supply current to safe-mode level (ISAFE = 0.5–1.5 mA). It automatically restarts once temperature drops to 180°C, enabling recovery without system reset - validated in DS41822 Rev. 6, Electrical Characteristics table, TTP/TTPR parameters.

Can Pin 2 (NC) be used as a heatsink or grounding point?

No - Pin 2 is internally unconnected per DS41822 Rev. 6, Pin Descriptions. It may be left floating, tied to VDD, or grounded based on mechanical or EMI layout needs, but it provides no thermal conduction path and contributes zero to RθJA (143 °C/W for SIP-3).