Skyworks Solutions Inc. SI8645BB-AS

Overview

SI8645BB-AS from Skyworks is a quad-channel, unidirectional digital isolator with 4 input channels on VDD1 side and 0 on VDD2 side, rated for 2.5 kVRMS isolation, 150 Mbps data rate, and –40 to 125 °C operation. It features Schmitt-trigger inputs, tri-state outputs with enable control, selectable fail-safe low-default output, and ultra-low power consumption (1.6 mA/channel @ 1 Mbps, 5 V).

For engineers reviewing the SI8645BB-AS datasheet, SI8645BB-AS pinout, SI8645BB-AS application, or SI8645BB-AS equivalent, this device serves as a high-reliability, AEC-Q100-qualified isolation solution for automotive battery management systems, on-board chargers, and industrial motor drives where reinforced insulation, precise timing (<10 ns propagation delay), and noise immunity (50 kV/µs CMTI) are critical.

Technical Context

The SI8645BB-AS implements RF-based on/off keying across a semiconductor isolation barrier-eliminating startup initialization and enabling robust noise immunity without optical degradation. Its architecture supports independent undervoltage lockout (UVLO) on both sides, with thresholds at 2.24 V (rising) and 2.16 V (falling), ensuring stable operation during supply transients.

All four channels are input-only on Side A (VDD1), driving outputs B1–B4 on Side B (VDD2); no enable pins are present per Table 3.2, confirming fixed-enable operation. The device uses internal 50 Ω output impedance and requires only 0.1 µF bypass capacitors per supply rail-no external components needed for basic functionality.

Key Specifications

Pinout & Package

SI8645BB-AS is housed in a RoHS-compliant wide-body SOIC-16 package (WB SOIC-16, -IS suffix), offering 8 mm creepage and reinforced insulation up to 2.5 kVRMS. Pin assignments follow standard Si864x layout with dual-side power/ground separation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SI8645BB-IS and ADUM140D0BRWZ, the SI8645BB-AS delivers automotive-grade reliability (AEC-Q100 Grade 0), lower power (5.5 vs. 10 mA/channel @ 100 Mbps), and tighter timing (8 ns vs. 10.5 ns typical propagation delay), making it optimal for high-integrity EV and industrial control systems requiring long-term supply continuity and safety certification.

Availability

SI8645BB-AS is available at Aetrix Electronics and suitable for automotive battery management systems, on-board chargers, and industrial motor control applications requiring stable component supply, long-lifecycle assurance, and certified reinforced isolation.

Supply support for SI8645BB-AS 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 designed specifically for high-reliability isolation in automotive electrification and industrial automation-delivering RF-based digital isolation with AEC-Q100 qualification, 60-year lifetime, and VDE 0884-10 reinforced certification.

FAQ

What is the isolation rating and certification status of the SI8645BB-AS?

The SI8645BB-AS provides 2.5 kVRMS reinforced isolation and is certified to UL 1577, CSA Component Notice 5A, VDE 0884-10 (basic insulation), IEC 62368-1, and CQC GB4943.1 standards. It meets reinforced insulation requirements for medical (IEC 60601-1) and industrial end-equipment, with full automotive AEC-Q100 Grade 0 qualification.

Does the SI8645BB-AS require external enable circuitry or pull-up resistors?

No. The SI8645BB-AS has no enable pins (per Table 3.2), operates in fixed-enable mode, and integrates Schmitt-trigger inputs with internal hysteresis. It requires only 0.1 µF bypass capacitors on VDD1 and VDD2-no external pull-ups, pull-downs, or enable logic are needed for basic operation.

What is the default output behavior of the SI8645BB-AS during input-side power loss?

The SI8645BB-AS is ordered with a "BB" suffix, indicating a low-default fail-safe mode. When VDD1 is unpowered but VDD2 remains active, outputs B1–B4 default to logic low within 12 ns (tSD), preventing unintended activation of downstream power stages-a critical safety feature in motor control and BMS applications.

How does the SI8645BB-AS achieve its 60 kV/µs common-mode transient immunity?

The SI8645BB-AS achieves 60 kV/µs CMTI through its RF-modulated isolation architecture and optimized internal layout, which minimizes coupling between input and output die. This performance is measured per VDE 0884-10 with 1500 V common-mode step and ensures reliable operation in high-dV/dt environments like SiC-based inverters and industrial SMPS.

Is the SI8645BB-AS pin-compatible with other Si864x variants in the same package?

Yes. All Si864x devices in the wide-body SOIC-16 (-IS/-AS) package share identical pinouts, including SI8645BB-AS, SI8645BA-AS, and SI8645BC-AS. Channel configuration (e.g., 4:0 vs. 2:2) and fail-safe default (low vs. high) are implemented internally-no PCB redesign is needed when substituting within the same package option.