Diodes Incorporated AH1897-FA-7

Overview

AH1897-FA-7 from Diodes Incorporated is a high-sensitivity, micropower omnipolar Hall-effect switch IC in X1-DFN1216-4 (Type D) package, operating from 1.6V to 3.6V with 4.3µA average supply current at 1.85V. It activates on either North or South magnetic pole, features internal pull-up/pull-down, and delivers BOP of ±14–40 Gauss and BRP of ±10–35 Gauss for reliable contactless switching in portable electronics.

For engineers reviewing the AH1897-FA-7 datasheet, AH1897-FA-7 pinout, AH1897-FA-7 application, or AH1897-FA-7 equivalent, key selection criteria include micropower operation (<5µA avg), omnipolar magnetic sensitivity, hibernating clock architecture, and compatibility with low-voltage battery-powered systems requiring robust RF noise immunity and thermal stability.

Technical Context

The AH1897 employs chopper-stabilized Hall sensing with offset cancellation and sleep/awake logic to achieve minimal switch-point drift over temperature (±10 Gauss variation across –40°C to +85°C) and supply voltage (1.6V–3.6V). Its hibernating clocking system cycles between 50µs awake time and ~100ms period, enabling ultra-low IDD(AVG) of 4.3µA at 1.8V.

It integrates latch and output driver circuitry with open-drain OUTPUT capable of sinking 3mA, while NC pin (Pin 3) is unconnected and may be left floating or grounded. The device requires no external pull-up resistor and uses a 100nF bypass capacitor (CIN) for power stabilization and enhanced RF noise immunity.

Key Specifications

Pinout & Package

Package: X1-DFN1216-4 (Type D), 1.2mm × 1.6mm × 0.5mm low-profile DFN with wettable flanks, RoHS-compliant and halogen-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AL3320EUST-7 and TLE4913-2D, the AH1897-FA-7 uniquely combines ultra-low power (4.3µA), omnipolarity, and 1.2×1.6mm DFN packaging-making it optimal for next-gen compact, battery-sensitive consumer devices where magnet placement flexibility and multi-year runtime are critical.

Availability

AH1897-FA-7 is available at Aetrix Electronics and suitable for cover-detect, open/close-sensing, and holster-detection applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing for consumer electronics production.

Supply support for AH1897-FA-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-efficiency power management, signal integrity, and precision sensing solutions.

The AH1897 belongs to Diodes' micropower Hall-effect switch product line, engineered specifically for battery-operated portable electronics demanding sub-5µA quiescent current, magnetic reliability, and minimal PCB footprint.

FAQ

What is the recommended bypass capacitor value for AH1897-FA-7?

A 100nF ceramic capacitor is recommended between VDD and GND, placed as close as possible to the device pins. This stabilizes the internal power rail during wake transitions and significantly improves immunity to RF noise from nearby cellular or Wi-Fi transceivers, as verified in Diodes' application testing per DS36470 Rev. 3-2.

Can Pin 3 (NC) be connected to ground?

Yes - Pin 3 is a true no-connect terminal with no internal bond wire or silicon connection. It may be left floating or tied to GND for improved mechanical anchoring during reflow soldering or to reduce potential EMI coupling; neither choice affects electrical performance or reliability.

Does AH1897-FA-7 require an external pull-up resistor?

No - the AH1897-FA-7 integrates internal pull-down and pull-up capability on the OUTPUT pin, eliminating the need for external resistors. Its open-drain output sinks current when active (low) and floats high when inactive, allowing direct interface to 1.8V or 3.3V microcontroller inputs without level-shifting.

How does the hibernating clock affect response time?

The hibernating clock wakes the sensor every ~100ms for a 50–100µs sampling window. While this introduces a worst-case latency of ~100ms, the output remains latched between samples - ensuring stable state reporting. For most cover-detect applications, this is imperceptible and fully compliant with USB and ACPI sleep/wake timing requirements.