Diodes Incorporated AH1822-FT4G-7

Overview

AH1822-FT4G-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 points, and -40°C to +85°C temperature range. It detects either north or south magnetic poles for cover-switch applications in clam-shell phones and notebook PCs.

For engineers reviewing the AH1822-FT4G-7 datasheet, AH1822-FT4G-7 pinout, AH1822-FT4G-7 application, or AH1822-FT4G-7 equivalent, key selection criteria include magnetic operate/release thresholds, ultra-low quiescent current, chopper-stabilized offset cancellation, RF noise immunity, and DFN2015 footprint compatibility with space-constrained portable designs.

Technical Context

The AH1822 integrates dual Hall plates with chopper-stabilized amplifiers and an internal latch to enable omnidirectional magnetic detection. Its architecture eliminates mechanical contact wear and provides stable switching with <8 Gauss hysteresis (Bhy) and minimal temperature drift over -40°C to +85°C.

It operates in low-power sampling mode with 75–150 µs awake time and 75–150 ms period, achieving average supply current as low as 8–28 µA across temperature and voltage. The open-drain output requires external pull-up and supports 1 mA sink capability with 0.1–0.3 V on-state voltage.

Key Specifications

Pinout & Package

X2-DFN2015-6 (2.0 mm × 1.5 mm × 0.39 mm), thermally enhanced, lead-free, halogen-free package with exposed thermal pad (not electrically connected). Pin 1 marked by corner chamfer; NC pins recommended tied to GND for stability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AL3421E-7 and US1881EUA-AAA-000, the AH1822-FT4G-7 uniquely balances ultra-low power (24 µW), true omnipolarity, and DFN2015 miniaturization-making it optimal for modern slim-profile battery-powered devices where magnet orientation flexibility and longevity are critical.

Availability

AH1822-FT4G-7 is available at Aetrix Electronics and suitable for clam-shell phone cover detection, notebook lid sensing, contactless wearable activation, and smart accessory docking requiring stable component supply, long-lifecycle support, and RoHS-compliant sourcing.

Supply support for AH1822-FT4G-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, energy-efficient components for consumer, industrial, and computing markets.

The AH1822 belongs to Diodes' Hall-effect sensor switch product line, engineered specifically for ultra-low-power, contactless position sensing in portable electronics where battery life, size, and magnetic robustness are primary design constraints.

FAQ

What is the minimum pull-up resistor value recommended for the AH1822-FT4G-7 output?

The datasheet specifies a recommended pull-up range of 10 kΩ to 100 kΩ. A 10 kΩ resistor ensures fast rise time and noise margin for 3.3 V logic interfaces, while 100 kΩ minimizes current draw in ultra-low-power sleep states. Values below 10 kΩ risk exceeding the 1 mA sink limit during output low state.

Does the AH1822-FT4G-7 require an external capacitor, and if so, what value?

Yes-a 10 nF to 100 nF ceramic decoupling capacitor is required between Vdd and GND, placed as close as possible to the device. This stabilizes the internal regulator, suppresses supply ripple, and enhances RF noise immunity per the datasheet's design guidance and typical application circuit.

Can the NC pins on the X2-DFN2015-6 package be left floating?

No-the datasheet explicitly recommends tying both NC pins (1 and 4) to GND. Doing so improves mechanical stability during reflow, reduces EMI susceptibility, and prevents parasitic coupling that could affect magnetic sensitivity or output noise performance in high-density layouts.

How does temperature affect the operate and release points of the AH1822-FT4G-7?

Magnetic thresholds vary with temperature: Bop and Brp shift approximately ±0.1% per °C, resulting in ~±10% total variation across -40°C to +85°C. The 5–8 G hysteresis remains stable, ensuring reliable chatter-free switching despite thermal drift-verified in the magnetic characteristics table and performance curves.