Skyworks Solutions Inc. SI8641BA-AU

Overview

SI8641BA-AU from Skyworks is a quad-channel, automotive-grade digital isolator with 3 input channels on VDD1 side and 1 output channel on VDD2 side, supporting up to 150 Mbps data rate, <10 ns propagation delay, and 1 kV RMS isolation rating in QSOP-16 package. It features Schmitt-trigger inputs, tri-state outputs with dedicated enable control, selectable fail-safe low-default output, and operates across –40 to 125 °C for battery management and traction inverter interfaces.

For engineers reviewing the SI8641BA-AU datasheet, SI8641BA-AU pinout, SI8641BA-AU application, or SI8641BA-AU equivalent, key selection criteria include channel asymmetry (3:1), AEC-Q100 qualification, fail-safe low default state, QSOP-16 footprint compatibility, and 2.5–5.5 V dual-supply operation with ultra-low power consumption at 100 Mbps.

Technical Context

The SI8641BA-AU 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 VDD1/VDD2 supplies (2.5–5.5 V), with separate undervoltage lockout monitors per side and precise timing control via internal oscillator modulation.

It integrates two dedicated enable inputs (EN1 on VDD1 side for A4; EN2 on VDD2 side for B1–B3), allowing independent tri-state control of input and output channels. The device uses Schmitt-trigger inputs (1.0–1.9 V hysteresis) and delivers 50 Ω nominal output impedance for controlled-impedance PCB routing, with CMTI rated ≥60 kV/µs under 1500 V common-mode transients.

Key Specifications

Pinout & Package

SI8641BA-AU is housed in a RoHS-compliant QSOP-16 package (5.3 mm × 10.2 mm, 1.0 mm height) with 0.635 mm pitch, optimized for high-density automotive PCB layouts and reflow-compatible at 260 °C peak temperature.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SI8641BA-AU, SI8641BB-AU offers higher isolation rating for elevated voltage domains, while ISO6741-Q1 trades bandwidth for TI's process consistency but lacks 150 Mbps capability needed in next-gen EV control loops.

Availability

SI8641BA-AU is available at Aetrix Electronics and suitable for battery management systems, traction inverters, on-board chargers, and charging station interfaces requiring stable component supply across automotive production lifecycles.

Supply support for SI8641BA-AU 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 Si864x family was designed specifically for high-reliability automotive and industrial isolation needs-delivering ultra-low power, precise timing, and AEC-Q100-compliant robustness in compact packages like QSOP-16.

FAQ

What is the default output state of SI8641BA-AU during input-side power loss?

The SI8641BA-AU is factory-configured with a fail-safe low default output state. When VDD1 is unpowered but VDD2 remains active, the B1–B3 outputs default to logic low-ensuring safe shutdown of downstream power stages. This behavior is confirmed in Table 1.1 of the Si864x datasheet and applies exclusively to "BA" ordering variants like SI8641BA-AU.

Does SI8641BA-AU support bidirectional signal flow?

Yes, SI8641BA-AU supports bidirectional isolation via its asymmetric 3:1 channel architecture: A1–A3 and EN1 operate on the VDD1 side, while B1–B3 and EN2 reside on the VDD2 side-and A4 provides a dedicated reverse-direction channel from VDD1 to VDD2. This enables combined upstream status reporting and downstream command transmission in a single QSOP-16 device.

What package type and footprint does SI8641BA-AU use?

SI8641BA-AU uses a QSOP-16 package (5.3 mm × 10.2 mm, 1.0 mm height, 0.635 mm pitch) with RoHS compliance and 260 °C peak reflow rating. Its land pattern matches standard JEDEC MO-131 specifications and is distinct from SOIC-16-requiring dedicated PCB layout to avoid mechanical fit or thermal issues.

How does the enable functionality work on SI8641BA-AU?

SI8641BA-AU has two independent enable inputs: EN1 (on VDD1 side) controls the A4 output, and EN2 (on VDD2 side) controls B1–B3 outputs. When either EN pin is driven low, its associated outputs enter high-impedance state-enabling dynamic signal gating without external switches. Truth table details are in Table 3.2 of the Si864x datasheet.

Is SI8641BA-AU certified for automotive applications?

Yes, SI8641BA-AU is AEC-Q100 qualified (Grade 1, –40 to 125 °C), manufactured using full automotive-specific process flows, and supported with AIAG-compliant PPAP documentation, IMDS, and CAMDS listings. The "-A" suffix explicitly denotes automotive-grade qualification per Skyworks' ordering guide.