Skyworks Solutions Inc. SI8405AB-A-IS1R

Overview

SI8405AB-A-IS1R from Skyworks Solutions is a 16-pin SOIC narrow-body bidirectional I²C isolator with two unidirectional digital channels, delivering 2500 VRMS galvanic isolation, 1.7 MHz I²C clock support, 35 mA SDA/SCL sink capability, and operation across –40 to +125 °C for industrial motor control and PoE power management systems.

For engineers reviewing the SI8405AB-A-IS1R datasheet, SI8405AB-A-IS1R pinout, SI8405AB-A-IS1R application, or SI8405AB-A-IS1R equivalent, this page provides verified electrical specs, safety-certified isolation parameters, channel-level timing data, and real-world design context for I²C bus segmentation in high-noise embedded systems.

Technical Context

The SI8405AB-A-IS1R implements RF-based on/off keying modulation across a semiconductor isolation barrier, enabling robust noise immunity (25 kV/µs CMTI) without startup initialization. It integrates independent UVLO monitors per side (AVDD/BVDD), with 2.3 V turn-on threshold and 75 mV hysteresis, ensuring reliable behavior during brownout conditions.

All four I²C channels (SDAA/SDAB/SCLA/SCLB) feature open-drain outputs with 35 mA sink current and logic thresholds compliant with SMBus/I²C standards; the two additional unidirectional channels (ADIN/BDOUT, ADOUT/BDIN) support CMOS-level signals up to 10 Mbps with 85 Ω nominal output impedance and <20 ns propagation delay.

Key Specifications

Pinout & Package

SI8405AB-A-IS1R is housed in a 16-pin narrow-body SOIC package (7.5 mm × 10.3 mm, 1.27 mm pitch) with creepage/clearance ≥4.01 mm and internal isolation barrier spanning pins 1–8 (Side A) and 9–16 (Side B).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I²C isolator applications.

Compared with ADUM1250ARZ and ISO1540DR, SI8405AB-A-IS1R uniquely combines 1.7 MHz I²C isolation, two 10 Mbps unidirectional channels, and 16-pin SOIC packaging-enabling single-chip segmentation of I²C plus critical control signals in motor drives and PoE systems without adding discrete logic or second isolators.

Availability

SI8405AB-A-IS1R is available at Aetrix Electronics and suitable for industrial motor control, Power over Ethernet, and intelligent power systems requiring stable component supply with long-term lifecycle assurance.

Supply support for SI8405AB-A-IS1R 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 global semiconductor company specializing in analog and mixed-signal connectivity solutions, with leadership in RF, timing, and isolation technologies.

The Si840x family was designed specifically for robust galvanic isolation of I²C/SMBus interfaces in harsh industrial and power electronics environments, leveraging proprietary RF isolation to replace aging optocoupler-based solutions.

FAQ

What is the maximum I²C clock frequency supported by SI8405AB-A-IS1R?

The SI8405AB-A-IS1R supports I²C clock frequencies up to 1.7 MHz, meeting fast-mode Plus specifications. This is confirmed in Table 6 of the Skyworks datasheet Rev. 1.6, where Fmax is specified as 1.7 MHz under all operating conditions (3.0–5.5 V, –40 to +125 °C). The SI8405AB-A-IS1R achieves this using low-propagation-delay RF isolation architecture, avoiding the timing limitations of optocoupler-based alternatives.

Does SI8405AB-A-IS1R include protection against hot-swap events?

Yes, SI8405AB-A-IS1R includes integrated hot-swap protection circuits that prevent data corruption when the device is inserted into a powered I²C bus. As stated in the "Description" section of the datasheet, all Si840x devices "contain protection circuits to guard against data errors if an unpowered device is inserted into a powered system." This ensures reliable operation in server backplanes and modular power systems.

How many isolation channels does SI8405AB-A-IS1R provide, and what are their directions?

The SI8405AB-A-IS1R provides four total isolation channels: two bidirectional I²C channels (SDA and SCL) and two unidirectional digital channels (ADIN/ADOUT for A→B, BDIN/BDOUT for B→A). This 2+2 configuration is unique to the Si8405 variant within the Si840x family and is explicitly documented in the "Description" and "Features" sections of the datasheet.

What safety certifications apply to SI8405AB-A-IS1R?

The SI8405AB-A-IS1R is certified to UL 1577 (2500 VRMS), CSA Component Notice 5A (IEC 60950-1/61010-1), and VDE 0884-2 (IEC 60747-5-2). These certifications are detailed in Tables 6 and 9 of the datasheet and confirm reinforced insulation suitability for industrial equipment, motor drives, and PoE applications requiring regulatory compliance.

What is the supply voltage range and operating temperature range for SI8405AB-A-IS1R?

The SI8405AB-A-IS1R operates from 3.0 V to 5.5 V on both AVDD and BVDD supplies, and functions across –40 °C to +125 °C ambient temperature. These values are specified in Table 1 (Absolute Maximum Ratings) and Table 2 (Power Characteristics) of the Skyworks datasheet Rev. 1.6, and are validated for continuous operation under full load and maximum frequency conditions.