Diodes Incorporated AH1822-FU4G-7

Overview

AH1822-FU4G-7 from Diodes Incorporated is a micropower omnipolar Hall-effect sensor switch in X2-DFN2015-6 package, featuring open-drain output, 2.5–5.5V operation, 24µW typical power at 3V, ±28–55 Gauss operate point, and -40°C to +85°C temperature range. It detects either north or south magnetic poles for cover-switch actuation in clam-shell phones and notebook lids.

For engineers reviewing the AH1822-FU4G-7 datasheet, AH1822-FU4G-7 pinout, AH1822-FU4G-7 application, or AH1822-FU4G-7 equivalent, key selection criteria include magnetic operate/release thresholds (Bop/Brp), ultra-low quiescent current (8–28 µA avg), chopper-stabilized offset cancellation, RF noise immunity, and NC pin grounding recommendation.

Technical Context

The AH1822-FU4G-7 integrates dual Hall plates with chopper-stabilized amplifiers and a latch-based logic circuit to enable bipolar magnetic field detection without polarity discrimination. Its internal architecture eliminates offset drift and supports stable switching across temperature.

It operates in a low-power sampling mode with 75–150 µs awake time and 75–150 ms period, delivering a 0.1% duty cycle to minimize average current draw. The open-drain output requires an external pull-up resistor (10kΩ–100kΩ) and benefits from a 10nF–100nF bypass capacitor for noise immunity.

Key Specifications

Pinout & Package

The AH1822-FU4G-7 is housed in a 2.0 mm × 1.5 mm × 0.39 mm X2-DFN2015-6 package with wettable flank leads and no exposed thermal pad. Pin 1 is marked by a corner chamfer; NC pins are internally unconnected and recommended to be tied to GND for mechanical stability and noise reduction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AL3320EUA-7 and US1881EUA-7, the AH1822-FU4G-7 uniquely balances omnipolar detection, wide supply range (2.5–5.5V), and ultra-low average current (8–28 µA) in a compact DFN-making it optimal for battery-powered clamshell and lid-sensing systems requiring design flexibility and field robustness.

Availability

AH1822-FU4G-7 is available at Aetrix Electronics and suitable for cover-switch actuation, contactless user interface, smart-appliance door sensing, and portable electronics lid detection requiring stable component supply across extended temperature and magnetic field variations.

Supply support for AH1822-FU4G-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, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.

The AH1822 belongs to Diodes' Hall-effect sensor product line, engineered specifically for ultra-low-power, battery-operated consumer and computing devices requiring reliable, polarity-agnostic magnetic switching in space-constrained layouts.

FAQ

What is the recommended pull-up resistor value for the AH1822-FU4G-7 open-drain output?

The datasheet specifies a recommended pull-up resistor range of 10 kΩ to 100 kΩ. A 47 kΩ resistor is commonly used to balance rise time, power consumption, and noise immunity. Lower values reduce rise time but increase static current; higher values minimize current but may degrade noise margin in electrically noisy environments.

Does the AH1822-FU4G-7 require an external bypass capacitor, and if so, what value?

Yes, a bypass capacitor between Vdd and GND is required for stable operation and enhanced RF noise immunity. The datasheet recommends 10 nF to 100 nF ceramic capacitors placed as close as possible to the Vdd and GND pins. A 22 nF X7R capacitor is widely adopted in production designs for optimal decoupling across frequency bands.

How does the NC pin (Pin 3 and Pin 6) affect PCB layout and thermal performance?

Pins 3 and 6 are internally unconnected but must be tied to GND on the PCB. This improves mechanical anchoring, reduces solder voiding risk, enhances thermal conduction from the die to the board, and lowers high-frequency impedance paths-contributing to better ESD robustness and long-term reliability in flex-circuit or hinge-mounted applications.

Can the AH1822-FU4G-7 operate reliably at 2.5V with full magnetic specification?

Yes, the device is fully specified down to 2.5V: Bop and Brp remain within ±28–55 Gauss and ±10–20 Gauss respectively, and average supply current stays within 8–28 µA across -40°C to +85°C. Performance validation at minimum Vdd ensures compatibility with aging alkaline or deeply discharged Li-ion cells in real-world portable deployments.