Skyworks Solutions Inc. SI83418BFA-IFR

Overview

SI83418BFA-IFR from Skyworks Solutions is a 4-channel isolated smart switch with galvanic isolation, configured as high-side switches delivering 700 mA continuous current per channel (RON = 155 mΩ) and supporting 9 V–32 V switch supply voltage. It integrates fault protection, diagnostics via SPI and open-drain indicator pins, and operates across –40 °C to +125 °C for industrial PLC output modules driving solenoids and relays.

For engineers reviewing the SI83418BFA-IFR datasheet, SI83418BFA-IFR pinout, SI83418BFA-IFR application, or SI83418BFA-IFR equivalent, key selection considerations include its parallel/SPI interface mode, absence of inrush current mode, lack of channel status indicators (LEDn), and compatibility with 2.25 V–5.5 V logic supplies in safety-isolated industrial I/O designs.

Technical Context

The SI83418BFA-IFR implements four independent high-side switches using RF-based CMOS isolation with 1.5 kVRMS safety rating and >100 kV/µs CMTI. Each channel features integrated voltage, current, and temperature sensing with autonomous fault response including overcurrent, overtemperature, and undervoltage shutdown.

It supports dual control paths: parallel digital inputs (A1–A4, OE) for real-time switching and an isolated SPI interface (MOSI, MISO, SCLK, NSS) for diagnostics and configuration. Diagnostic reporting includes eight distinct fault types-e.g., open-circuit, communication error, supply warnings-with status accessible via registers or dedicated FLT pin.

Key Specifications

Pinout & Package

SI83418BFA-IFR is housed in a compact 9 mm × 9 mm DFN-32 package with exposed thermal pad, optimized for high-density industrial PCB layouts and thermal dissipation in sealed enclosures.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar isolated high-side switch applications.

Compared with SI83418BFA-IFR, SI83418AFA-IFR adds inrush support for resistive loads but increases complexity, while SI83414BFA-IFR reduces pin count and diagnostic granularity at the expense of field-serviceability in safety-critical I/O modules.

Availability

SI83418BFA-IFR is available at Aetrix Electronics and suitable for programmable logic controllers, industrial data acquisition systems, and motion controllers requiring stable component supply, long-term lifecycle assurance, and traceable sourcing for industrial automation OEMs.

Supply support for SI83418BFA-IFR 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

Skyworks Solutions is a U.S.-based semiconductor company specializing in analog and mixed-signal connectivity solutions, with leadership in RF, timing, and isolation technologies for high-reliability applications.

The Si834x product line was designed specifically for industrial I/O consolidation - replacing optocoupler-based relay drivers with integrated, fault-aware, digitally configurable isolated switches meeting IEC 61131-2 and safety certification requirements.

FAQ

What is the isolation architecture used in SI83418BFA-IFR?

The SI83418BFA-IFR uses Skyworks' proprietary RF-based CMOS isolation technology, not optocouplers or capacitive isolation. This architecture modulates an RF carrier across the isolation barrier, achieving 1.5 kVRMS rating and >100 kV/µs common-mode transient immunity. It avoids LED degradation and provides deterministic propagation delay, making SI83418BFA-IFR suitable for time-critical industrial control loops where reliability over 10+ years is required.

Does SI83418BFA-IFR support inrush current handling for lamp loads?

No, SI83418BFA-IFR does not include Inrush Current Mode. Per the Skyworks ordering guide, only variants ending in "AFA" (e.g., SI83418AFA-IFR) provide 8 A inrush capability for 20 ms. SI83418BFA-IFR is intended for steady-state loads like solenoids and relays where inrush is not a design concern. Using SI83418BFA-IFR with incandescent lamps may cause premature failure due to cold-filament surge currents exceeding 700 mA.

How are diagnostics accessed on SI83418BFA-IFR?

Diagnostics on SI83418BFA-IFR are accessible via two independent paths: (1) the isolated SPI interface (MOSI/MISO/SCLK/NSS), which reads eight diagnostic registers including open-circuit, overtemperature, and communication errors; and (2) the active-low open-drain FLT pin, which asserts whenever any diagnostic fault is active. Unlike some variants, SI83418BFA-IFR does not expose individual channel status on LEDn pins - all status reporting relies on SPI or the shared FLT signal.

What is the function of the OE pin on SI83418BFA-IFR?

The OE (Output Enable) pin on SI83418BFA-IFR provides asynchronous, hardware-level disable of all four high-side switches regardless of A1–A4 input states or SPI configuration. When OE is pulled low, B1–B4 immediately enter high-impedance off-state - a critical feature for emergency stop circuits and functional safety architectures. This behavior is guaranteed even during power-up, brownout, or communication faults, ensuring SI83418BFA-IFR meets fail-safe design requirements in industrial safety applications.

Can SI83418BFA-IFR be used with 3.3 V microcontrollers?

Yes, SI83418BFA-IFR is fully compatible with 3.3 V microcontrollers. Its logic supply range is 2.25 V–5.5 V, and its parallel inputs (A1–A4, OE) accept 3.3 V logic levels directly - no level-shifting circuitry is required. The device's 2.25 V minimum threshold ensures robust operation even with marginal MCU I/O drive strength or PCB trace losses, making SI83418BFA-IFR suitable for low-power industrial edge nodes powered by 3.3 V rails.