Skyworks Solutions Inc. SI8661AB-AS1R

Overview

SI8661AB-AS1R from Skyworks is a six-channel automotive-grade digital isolator with 5-channel input / 1-channel output configuration, 2.5 kV_RMS isolation rating, and SOIC-16 narrow-body package. It supports DC–150 Mbps data rates, achieves <10 ns propagation delay, and operates across –40 to +125 °C for battery management systems and on-board chargers.

For engineers reviewing the SI8661AB-AS1R datasheet, SI8661AB-AS1R pinout, SI8661AB-AS1R application, or SI8661AB-AS1R equivalent, this page delivers verified electrical specs, fail-safe mode behavior, CMTI immunity (50 kV/µs), AEC-Q100 qualification, and precise channel skew (0.5 ns) - all critical for high-reliability EV powertrain designs.

Technical Context

The SI8661AB-AS1R implements RF-based on/off keying across a semiconductor isolation barrier, eliminating startup initialization and enabling robust noise immunity without optical degradation. Its dual-supply architecture (VDD1/VDD2) supports independent 2.5–5.5 V operation per side with Schmitt-trigger inputs and undervoltage lockout (UVLO) on both domains.

It features selectable fail-safe mode (default low output during input-side power loss), 50 Ω nominal output impedance, and reinforced insulation certified to UL 1577, VDE 0884-10, and IEC 62368-1. The device meets AEC-Q100 Grade 1 requirements and supports AIAG-compliant PPAP documentation.

Key Specifications

Pinout & Package

SI8661AB-AS1R uses a 16-pin narrow-body SOIC package (5.3 mm width, 10.3 mm length) with creepage ≥8.0 mm and clearance ≥7.9 mm per IEC 60664-1. Pin functions are defined per Skyworks datasheet Section 5 (Pin Descriptions).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SI8661BB-AS1, SI8661AB-AS1R adds automotive process controls and certification evidence required for Tier 1 BMS qualification; versus ADUM6601ARWZ, it trades integrated power for superior timing precision and smaller footprint - making it optimal for high-speed signal-only isolation in space-constrained EV power electronics.

Availability

SI8661AB-AS1R is available at Aetrix Electronics and suitable for battery management systems, on-board chargers, traction inverters, and DC fast charging stations requiring stable component supply across automotive production lifecycles.

Supply support for SI8661AB-AS1R 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 for wireless, automotive, and industrial markets.

The SI866x family was designed specifically for high-reliability automotive and industrial isolation needs, emphasizing ultra-low power, precise timing, and robust CMTI performance in harsh EMI environments.

FAQ

What is the default output state of SI8661AB-AS1R during input-side power loss?

The SI8661AB-AS1R has a selectable fail-safe mode configured at manufacture; the "AB" suffix indicates default-low output behavior when VDD1 is unpowered but VDD2 remains active. This prevents undefined logic states in safety-critical paths like gate driver enable lines, and is confirmed in Table 1.1 of the Skyworks datasheet.

Does SI8661AB-AS1R require external startup initialization or configuration registers?

No, SI8661AB-AS1R requires no startup initialization or register programming. It begins transmitting valid data within 40 µs of VDD1/VDD2 reaching UVLO thresholds, as specified in the Electrical Specifications table (tSU = 15–40 µs). This zero-config operation is inherent to its RF modulation architecture.

What is the maximum ambient temperature rating for continuous operation of SI8661AB-AS1R?

SI8661AB-AS1R is rated for continuous operation from –40 to +125 °C ambient temperature, validated per AEC-Q100 Grade 1 requirements. This rating holds across full data rate (150 Mbps) and supply range (2.5–5.5 V), with junction temperature limited to 150 °C per datasheet Table 4.1.

How does the channel configuration of SI8661AB-AS1R differ from SI8660AB-AS1R?

SI8661AB-AS1R provides five input channels and one output channel (5+1), whereas SI8660AB-AS1R offers six input channels and zero outputs (6+0). This asymmetric configuration makes SI8661AB-AS1R ideal for applications like BMS where multiple sensor inputs feed a single fault-reporting output across the isolation barrier.

Is SI8661AB-AS1R compatible with 2.5 V logic interfaces on both sides?

Yes, SI8661AB-AS1R supports 2.5 V operation on both VDD1 and VDD2 supplies, delivering 1.5 mA/channel at 1 Mbps and 3.5 mA/channel at 100 Mbps per side. Input thresholds (VT+ = 1.67 V typ., VT– = 1.23 V typ.) and output drive strength (VOH ≥ VDD–0.4 V) ensure robust interfacing with 2.5 V CMOS logic.