Diodes Incorporated AH1897S-FAN-7

Overview

AH1897S-FAN-7 from Diodes Incorporated is a high-sensitivity, micropower omnipolar Hall-effect switch IC in X1-DFN1216-4 (Type B) 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, chopper-stabilized architecture for thermal stability, and targets cover-open detection in portable electronics.

For engineers reviewing the AH1897S-FAN-7 datasheet, AH1897S-FAN-7 pinout, AH1897S-FAN-7 application, or AH1897S-FAN-7 equivalent, key selection criteria include magnetic operate/release points (±14–40 Gauss), ultra-low IDD(avg), hibernating clocking system, and NC-pin handling in PCB layout.

Technical Context

The AH1897S-FAN-7 implements a chopper-stabilized Hall sensor with sleep/awake logic that cycles at ~100ms period and 50–100µs awake time, minimizing average current draw. Its latch-and-output driver architecture delivers push-pull output without external resistors.

Magnetic switching is defined by bipolar hysteresis: Bop (±14–40 G) and Brp (±10–35 G), with <10G typical hysteresis (BHY). Temperature drift of switch points is minimized across –40°C to +85°C via offset cancellation and stabilized amplification.

Key Specifications

Pinout & Package

Package: X1-DFN1216-4 (Type B), 1.2mm × 1.6mm × 0.48mm, no exposed pad, NiPdAu-plated copper leadframe, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AL33201ELTTR and TMAG5170AHQDBVR, the AH1897S-FAN-7 uniquely combines omnipolar detection, sub-5µA average current, and push-pull output in a 1.2×1.6mm DFN - making it optimal for space-constrained, battery-sensitive cover-switch designs where polarity-agnostic mounting is essential.

Availability

AH1897S-FAN-7 is available at Aetrix Electronics and suitable for cover-switch detection in portable PCs, open/close sensing in cellular phones, and holster-detect functions in tablet PCs requiring stable component supply and long-term lifecycle support.

Supply support for AH1897S-FAN-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, serving automotive, industrial, computing, and consumer markets with high-reliability components.

The AH1897S belongs to Diodes' micropower Hall-effect switch product line, designed specifically for ultra-low-power magnetic presence detection in battery-operated portable devices where size, current budget, and mechanical mounting flexibility are critical.

FAQ

What is the maximum magnetic flux density the AH1897S-FAN-7 can withstand without damage?

The AH1897S-FAN-7 has no specified maximum magnetic flux density limit in its absolute ratings - it is designed for continuous operation under magnetic fields exceeding its operate point (±40 G max). The device uses robust Hall plate and chopper architecture to avoid saturation or parametric shift even at strong static fields, as confirmed in DS37559 Rev. 2–2 Section 4.

Can Pin 3 (NC) be used as a thermal pad or grounded for improved thermal performance?

No - Pin 3 is internally unconnected and not bonded to the die or leadframe. Diodes Incorporated explicitly states it may be left open or tied to GND for mechanical stability only; using it as a thermal path provides no benefit, as the X1-DFN1216-4 (Type B) package has no exposed thermal pad and relies on solder joint conduction through Pins 1 and 2.

Does the AH1897S-FAN-7 require an external capacitor, and what happens if it is omitted?

Yes - a 100nF ceramic capacitor (CIN) between VDD and GND is recommended per DS37559 Rev. 2–2 Section 2. Omitting it degrades RF noise immunity and may cause erratic switching under ESD or GSM burst noise, as verified in Diodes' application testing; the capacitor stabilizes the internal hibernating clock and supply rail during wake transitions.

How does the hysteresis (BHY) of the AH1897S-FAN-7 improve system reliability in mechanical applications?

The ≥10G hysteresis prevents output oscillation when the magnet is near the operate point - critical in lid or cover mechanisms where mechanical vibration or slow-motion alignment causes field fluctuations. This ensures clean, bounce-free transitions, eliminating the need for software debouncing and reducing MCU interrupt load in portable systems.