Skyworks Solutions Inc. SI8405AA-B-IS1R

Overview

SI8405AA-B-IS1R from Skyworks Solutions is a 16-pin SOIC narrow-body bidirectional I²C isolator with two unidirectional digital channels, supporting up to 1.7 MHz I²C clock rates and 10 Mbps non-I²C data rates, delivering 2500 VRMS galvanic isolation for isolated power supply communications in motor control systems.

For engineers reviewing the SI8405AA-B-IS1R datasheet, SI8405AA-B-IS1R pinout, SI8405AA-B-IS1R application, or SI8405AA-B-IS1R equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, and confirmed alternative options for I²C/SMBus isolation in high-noise industrial environments.

Technical Context

The SI8405AA-B-IS1R implements RF-based galvanic isolation using on/off keying modulation across a semiconductor barrier, enabling robust noise immunity (25 kV/µs CMTI) without startup initialization. It integrates independent bidirectional SDA/SCL isolation plus two unidirectional CMOS channels for interrupt/reset signaling.

Each side features independent under-voltage lockout (UVLO+ = 2.3 V, hysteresis = 75 mV), hot-swap capability, and open-drain I²C outputs with 35 mA sink current on Side B. The device operates from 3.0–5.5 V across –40 to +125 °C with 85 Ω nominal output impedance on non-I²C channels.

Key Specifications

Pinout & Package

SI8405AA-B-IS1R uses 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 separating pins 1–8 (Side A) from pins 9–16 (Side B).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADUM1250ARZ and ISO1540DR, SI8405AA-B-IS1R delivers higher I²C bandwidth (1.7 MHz vs. ≤1 Mbps), integrated unidirectional channels for system signaling, and superior CMTI (25 kV/µs), making it optimal for noise-intensive motor control and intelligent PSU applications requiring auxiliary signal isolation.

Availability

SI8405AA-B-IS1R is available at Aetrix Electronics and suitable for motor control systems, Power over Ethernet infrastructure, intelligent power supplies, and industrial hot-swap modules requiring stable component supply with long-term lifecycle assurance.

Supply support for SI8405AA-B-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, low-power galvanic isolation of I²C and SMBus interfaces in harsh industrial and automotive environments where reliability and noise immunity are critical.

FAQ

What is the maximum I²C clock frequency supported by SI8405AA-B-IS1R?

The SI8405AA-B-IS1R supports I²C clock frequencies up to 1.7 MHz, enabling full-speed SMBus operation and compatibility with standard-mode and fast-mode I²C protocols. This specification is validated across the full operating temperature range (–40 to +125 °C) and supply range (3.0–5.5 V), ensuring reliable timing margin for arbitration and ACK cycles in real-world systems.

Does SI8405AA-B-IS1R support hot-swap insertion into a live I²C bus?

Yes, SI8405AA-B-IS1R includes integrated hot-swap protection circuitry that prevents data corruption when inserted into a powered system. The device safely handles unpowered-side insertion by holding outputs low until both AVDD and BVDD exceed UVLO thresholds, then synchronizing to input states within 1 µs - a feature explicitly documented in Table 12 of the Skyworks datasheet.

How many isolation channels does SI8405AA-B-IS1R provide, and what are their types?

SI8405AA-B-IS1R provides four total isolation channels: two bidirectional I²C channels (SDA and SCL) and two unidirectional CMOS digital channels (CH1 and CH2). The bidirectional channels support open-drain I²C signaling with 35 mA sink capability on Side B, while the unidirectional channels operate at up to 10 Mbps with 85 Ω output impedance for clean signal edge integrity.

What safety certifications apply to SI8405AA-B-IS1R?

SI8405AA-B-IS1R is certified to UL 1577 (2500 VRMS), CSA Component Notice 5A (IEC 60950-1/61010-1), and VDE IEC 60747-5-2 (560 Vpeak working voltage). These certifications cover reinforced insulation with minimum creepage/clearance of 4.01 mm and are production-tested to 3000 VRMS for 1 second, confirming compliance for industrial and medical end-equipment safety standards.

Can SI8405AA-B-IS1R operate with different supply voltages on Side A and Side B?

Yes, SI8405AA-B-IS1R supports independent 3.0–5.5 V supplies on AVDD and BVDD, enabling interoperability between 3.3 V microcontrollers and 5 V peripheral ICs across the isolation barrier. Each side has its own UVLO monitor (2.3 V threshold, 75 mV hysteresis), allowing asymmetric power-up sequences without latch-up or undefined output states - a key requirement in modular power system designs.