Skyworks Solutions Inc. SI8605AB-B-IS1R

Overview

SI8605AB-B-IS1R from Skyworks Solutions is a bidirectional I²C isolator with two unidirectional non-I²C channels, designed for galvanic isolation of I²C/SMBus buses in high-noise or safety-critical systems. It supports 1.7 MHz I²C clock rates, provides 2.5 kVRMS isolation, features open-drain SDA/SCL outputs with 35 mA sink capability, and operates across –40 to +125 °C with 3.0–5.5 V supply rails.

For engineers reviewing the SI8605AB-B-IS1R datasheet, SI8605AB-B-IS1R pinout, SI8605AB-B-IS1R application, or SI8605AB-B-IS1R equivalent, this device delivers verified anti-latch bidirectional I²C isolation plus two independent 10 Mbps unidirectional digital channels-ideal for isolated reset/interrupt signaling in automotive BMS, PoE controllers, and industrial motor drives where ground-loop elimination and AEC-Q100 compliance are required.

Technical Context

The SI8605AB-B-IS1R implements RF-based semiconductor isolation with separate transmitter/receiver blocks per channel, enabling robust noise immunity (50 kV/µs transient immunity) and stable operation over temperature and lifetime. Its anti-latch architecture ensures reliable bidirectional I²C communication without external circuitry by enforcing ΔVSDA/ΔVSCL ≥ 50 mV between Side A output low and input threshold.

Side A handles bidirectional I²C (SDA/SCL), while Side B includes two unidirectional CMOS-compatible channels supporting 10 Mbps data rates and standard logic thresholds (VT+ = 1.67 V typ, VT– = 1.23 V typ). Undervoltage lockout (UVLO) operates independently on AVDD and BVDD, and hot-swap protection prevents data corruption during live insertion.

Key Specifications

Pinout & Package

SI8605AB-B-IS1R is housed in a RoHS-compliant narrow-body SOIC-16 package (5.3 mm × 10.3 mm, 1.27 mm pitch), optimized for space-constrained PCB layouts while meeting creepage/clearance requirements for 2.5 kVRMS working voltage.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADUM1250ARZ and ISO1540DR, SI8605AB-B-IS1R uniquely integrates two 10 Mbps unidirectional channels alongside anti-latch I²C isolation-reducing BOM count and PCB area while delivering automotive-grade reliability and superior noise immunity.

Availability

SI8605AB-B-IS1R is available at Aetrix Electronics and suitable for automotive battery management systems, Power over Ethernet infrastructure, and industrial motor control applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for SI8605AB-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 leader in analog and mixed-signal semiconductors, specializing in RF, timing, isolation, and connectivity solutions for high-performance wireless and wired systems.

The SI860x family was engineered specifically for robust, low-latency galvanic isolation of I²C/SMBus interfaces in automotive, industrial, and PoE applications-leveraging proprietary RF isolation technology to replace optocouplers with superior speed, power efficiency, and lifetime stability.

FAQ

What is the maximum I²C clock frequency supported by SI8605AB-B-IS1R?

The SI8605AB-B-IS1R supports I²C bus speeds up to 1.7 MHz, as verified in Table 5.3 of the official datasheet. This enables full-speed operation including clock stretching in SMBus-compliant systems. The timing is guaranteed across the full –40 to +125 °C temperature range and 3.0–5.5 V supply voltage, with propagation delays ranging from 11 to 45 ns depending on voltage and signal edge.

Does SI8605AB-B-IS1R require external anti-latch circuitry for I²C operation?

No, SI8605AB-B-IS1R does not require external anti-latch circuitry. Its integrated anti-latch design enforces a minimum 50 mV difference between Side A's output low voltage (VOL) and input threshold (VT), preventing bus latching during bidirectional communication. This is confirmed in Section 3.2 and Table 3.1 of the datasheet, and eliminates the need for discrete components or complex layout constraints.

What are the key differences between SI8605AB-B-IS1R and SI8602AB-B-IS?

SI8605AB-B-IS1R provides two bidirectional I²C channels (SDA/SCL) plus two unidirectional non-I²C channels (RESET/INT), whereas SI8602AB-B-IS offers one bidirectional I²C channel and one unidirectional channel. SI8605AB-B-IS1R uses a 16-pin narrow-body SOIC package, while SI8602AB-B-IS uses an 8-pin narrow-body SOIC. Both share identical 1.7 MHz I²C speed, 2.5 kVRMS rating, and AEC-Q100 qualification.

Is SI8605AB-B-IS1R qualified for automotive applications?

Yes, SI8605AB-B-IS1R is AEC-Q100 Grade 1 qualified and built using automotive-specific manufacturing flows, including AIAG-compliant PPAP documentation, IMDS/CAMDS listings, and zero-defect methodology. Its top marking includes an automotive manufacturing code (first character N–Z), and it meets requirements for on-board chargers, battery management systems, and traction inverters per the datasheet's Automotive Applications section.

What is the purpose of the unidirectional channels in SI8605AB-B-IS1R?

The two unidirectional channels in SI8605AB-B-IS1R support auxiliary system signals such as RESET and INTERRUPT, operating at up to 10 Mbps with standard CMOS logic thresholds. They eliminate the need for separate isolators in designs requiring isolated control signaling alongside I²C telemetry-reducing component count, PCB area, and bill-of-materials complexity while maintaining timing integrity and noise immunity.