Diodes Incorporated AH3321Q-SA-7

Overview

AH3321Q-SA-7 from Diodes Incorporated is an AEC-Q100 Grade 0 qualified high-voltage Hall-effect unipolar switch IC designed for automotive position and proximity sensing. It operates from 3.0V to 28V, features BOP of 235–300 G and BRP of 210–275 G (SOT23-Type S package), delivers 60 mA output current limit, and supports –40°C to +150°C ambient operation - used in seatbelt buckle detection and gear position sensing.

For engineers reviewing the AH3321Q-SA-7 datasheet, AH3321Q-SA-7 pinout, AH3321Q-SA-7 application, or AH3321Q-SA-7 equivalent, key selection criteria include magnetic operate/release thresholds, open-drain output drive capability, load dump tolerance, thermal derating at elevated ambient temperatures, and polarity alignment relative to package marking side.

Technical Context

The AH3321Q-SA-7 uses chopper-stabilized architecture with dynamic offset cancellation to minimize temperature-induced switch point drift, achieving ±0.5 G/°C typical BOP drift over –40°C to +150°C. Its internal bandgap regulator supplies temperature-compensated bias to analog blocks, enabling stable operation across full automotive voltage and thermal ranges.

It implements a single open-drain output with integrated overcurrent limiting (30–55 mA) and zener clamps on both VDD and OUTPUT pins, supporting robust 40 V load dump survival and reverse supply protection down to –18 V. Magnetic actuation requires South pole applied to the part marking side for the SOT23 (Type S) package variant.

Key Specifications

Pinout & Package

Package: SOT23 (Type S), 3-pin, surface-mount, lead-free and RoHS-compliant. Thermal resistance θ_JA = 391°C/W; maximum power dissipation = 230 mW at T_A = 25°C, derating linearly to 0 mW at 150°C.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Hall-effect unipolar switch applications.

Compared with AL3321Q-SA-7 and TLE4913-2SA, the AH3321Q-SA-7 offers fastest startup (10 µs), highest ESD rating (8 kV HBM), and lowest cost per unit in high-volume automotive programs - making it optimal for cost-sensitive, high-reliability seat and closure sensing.

Availability

AH3321Q-SA-7 is available at Aetrix Electronics and suitable for seatbelt buckle detection, steering lock verification, and transmission gear position sensing requiring stable component supply across multi-year automotive production cycles.

Supply support for AH3321Q-SA-7 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 solutions for automotive, industrial, and computing markets with IATF 16949-certified manufacturing.

The AH332XQ series belongs to Diodes' AEC-Q100-qualified Hall-effect sensor product line, engineered specifically for contactless position sensing in harsh automotive environments where extended temperature operation and transient immunity are mandatory.

FAQ

What is the magnetic polarity requirement for AH3321Q-SA-7 activation?

The AH3321Q-SA-7 uses SOT23 (Type S) packaging, which requires a South pole applied to the part marking side to activate the output. This polarity alignment is confirmed in the datasheet's magnetic characteristics table and pin diagrams. Applying North pole or misaligned orientation results in no switching action.

Does AH3321Q-SA-7 require an external bypass capacitor?

Yes - a 10 nF to 100 nF ceramic capacitor (CIN) between VDD and GND is recommended per the datasheet to stabilize the internal regulator and improve RF noise immunity. Omitting CIN may cause erratic switching under EMI stress or during load dump events, especially in high-frequency automotive harness environments.

Can AH3321Q-SA-7 drive an LED directly?

No - its open-drain output is rated for 60 mA continuous sink current, but driving an LED directly risks exceeding safe operating area due to lack of current limiting. A series resistor must be used to limit current to ≤20 mA (per V_{OUT_ON} = 0.4 V max at 20 mA). For indicator use, pair with a 220 Ω–1 kΩ resistor depending on supply voltage and LED forward voltage.

How does thermal derating affect AH3321Q-SA-7 performance at 125°C ambient?

At 125°C ambient, the SOT23 (Type S) package's power dissipation drops to 55 mW (from 230 mW at 25°C), limiting maximum continuous output current to ~25 mA. However, magnetic switching parameters (BOP/BRP) remain fully specified and functional - only thermal shutdown or excessive junction temperature becomes a concern under sustained high-current loads.