Skyworks Solutions Inc. SI8645BD-ASR

Overview

SI8645BD-ASR from Skyworks is a quad-channel, 4-input/0-output digital isolator with 5 kV_RMS reinforced isolation, 150 Mbps data rate, and fail-safe default-low output state. It operates from 2.5–5.5 V on both sides, delivers <10 ns propagation delay, and supports industrial and automotive systems requiring high noise immunity and long-term reliability across –40 to 125 °C.

For engineers reviewing the SI8645BD-ASR datasheet, SI8645BD-ASR pinout, SI8645BD-ASR application, or SI8645BD-ASR equivalent, this device serves as a drop-in replacement for legacy optocouplers in isolated gate drivers, battery management interfaces, and industrial PLC I/O modules where low power, precise timing, and safety certification are critical.

Technical Context

The SI8645BD-ASR implements RF-based on/off keying across a silicon-die isolation barrier-eliminating startup initialization and enabling robust operation without external components beyond 0.1 µF bypass capacitors. Its Schmitt-trigger inputs provide >0.4 V hysteresis for noise rejection in noisy motor control or power supply environments.

All four channels reside on Side A (input) and drive outputs on Side B (isolated side), with no enable pins (EN1/EN2 not implemented per Si8645 family definition). The device uses dual independent UVLO monitors (VDD1/VDD2) and supports fail-safe behavior during input-side power loss, holding outputs low when VDD1 = 0 V and VDD2 is powered.

Key Specifications

Pinout & Package

SI8645BD-ASR is housed in a RoHS-compliant wide-body SOIC-16 package (WB SOIC-16, -IS suffix), offering 8 mm creepage and reinforced insulation for 5 kV_RMS operation. Pin assignments follow standard Si864x layout with isolation barrier between Pins 1–8 (Side A) and Pins 9–16 (Side B).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADUM2402BRWZ and ISO6741QDWR, SI8645BD-ASR uniquely combines 150 Mbps speed, 60 kV/µs CMTI, VDE-reinforced 5 kV_RMS, and AEC-Q100 Grade 0 (–40 to 125 °C) in a single device-making it optimal for next-gen EV inverters and high-bandwidth industrial automation where timing precision and safety certification are non-negotiable.

Availability

SI8645BD-ASR is available at Aetrix Electronics and suitable for industrial motor control, automotive battery management systems, isolated switch-mode power supplies, and programmable logic controller I/O requiring stable component supply across extended temperature and safety-critical environments.

Supply support for SI8645BD-ASR 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 Si864x family was engineered to replace optocouplers in high-reliability industrial and automotive systems, delivering superior speed, power efficiency, and safety certification while eliminating LED aging and temperature drift limitations.

FAQ

What is the isolation rating and certification status of SI8645BD-ASR?

SI8645BD-ASR provides 5 kV_RMS reinforced isolation certified to UL 1577, VDE 0884-10 (reinforced), CSA 5A, and CQC GB4943.1 standards. This qualifies it for use in medical equipment (IEC 60601-1) and EV traction inverters where reinforced insulation is mandated. The certification applies specifically to the WB SOIC-16 package variant denoted by the "-AS" suffix in SI8645BD-ASR.

Does SI8645BD-ASR support fail-safe operation, and how is it configured?

Yes, SI8645BD-ASR is factory-configured for fail-safe default-low output: when VDD1 is unpowered but VDD2 remains active, all four outputs (B1–B4) drive logic low. This behavior is fixed per ordering code "BD" and does not require external configuration. It ensures safe shutdown of downstream power stages during input-side power loss-a critical feature in motor drives and battery disconnect circuits.

What are the supply voltage requirements for SI8645BD-ASR?

SI8645BD-ASR operates with independent 2.5–5.5 V supplies on both sides: VDD1 (Pins 1/2) powers the input logic and RF transmitter, while VDD2 (Pins 9/10) powers the isolated output drivers. Each supply requires a local 0.1 µF ceramic bypass capacitor. The device functions correctly with mismatched voltages (e.g., 3.3 V on Side A, 5 V on Side B), enabling flexible interfacing across mixed-voltage systems.

How does SI8645BD-ASR achieve its 150 Mbps data rate without external components?

SI8645BD-ASR achieves 150 Mbps using an integrated RF modulation architecture-encoding input data onto a high-frequency carrier that crosses the isolation barrier, then demodulating it on the output side. This eliminates the need for external oscillators, PLLs, or initialization sequences. Schmitt-trigger inputs and optimized output drivers further enable clean edge transitions at full speed without external termination resistors under typical 15 pF loads.

Is SI8645BD-ASR qualified for automotive applications, and what does the "-A" suffix indicate?

Yes, SI8645BD-ASR carries the "-A" suffix, signifying full AEC-Q100 Grade 0 qualification (–40 to 125 °C ambient), AIAG-compliant PPAP documentation, and automotive-specific manufacturing flow. The "-ASR" ending denotes tape-and-reel packaging. This makes SI8645BD-ASR suitable for on-board chargers, battery management systems, and traction inverters where zero-defect reliability and traceable material data (IMDS/CAMDS) are required.