Skyworks Solutions Inc. SI8651BC-AS1R

Overview

SI8651BC-AS1R from Skyworks is a five-channel, ultra-low-power digital isolator with 4 input channels on VDD1 side and 1 output channel on VDD2 side, 3.75 kVRMS reinforced isolation rating, 150 Mbps data rate, and fail-safe default-low output state. It operates across –40 to +125 °C and supports 2.5–5.5 V dual supplies for industrial motor control and isolated ADC interfaces.

For engineers reviewing the SI8651BC-AS1R datasheet, SI8651BC-AS1R pinout, SI8651BC-AS1R application, or SI8651BC-AS1R equivalent, key selection criteria include channel asymmetry (4:1), narrow-body SOIC-16 package, 3.75 kV isolation certification (UL, VDE, CQC), and tri-state enable control for output-side signal management.

Technical Context

The SI8651BC-AS1R implements RF-based on/off keying across a semiconductor isolation barrier, eliminating startup initialization and enabling robust noise immunity without optical degradation. Its architecture delivers sub-10 ns propagation delay with ≤2.5 ns channel-channel skew and ≤4.5 ns propagation delay skew across temperature.

It features independent undervoltage lockout (UVLO) on both sides (VDD1/VDD2), Schmitt-trigger inputs (0.44 V hysteresis), and dual enable pins (EN1 on Side A, EN2 on Side B) supporting independent tri-state control of the single output channel (A5) and four output channels (B1–B4).

Key Specifications

Pinout & Package

Narrow-body SOIC-16 (NB SOIC-16) package, RoHS-compliant, 260 °C peak reflow, 1.27 mm pitch, 10.3 mm × 7.5 mm footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SI8651BB-AS1, SI8651BC-AS1R provides higher isolation margin for 800 V battery systems; compared with ADUM141E0BRZ, it adds a fifth configurable output and achieves 50% higher data rate with 30% lower active power at 100 Mbps.

Availability

SI8651BC-AS1R is available at Aetrix Electronics and suitable for industrial motor control, battery management systems, isolated ADC interfaces, and programmable logic controller I/O modules requiring stable component supply and long-term lifecycle support.

Supply support for SI8651BC-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.

The Si865x family was designed for high-reliability industrial and automotive isolation applications demanding low power, precise timing, and certified reinforced insulation-targeting motor drives, EV powertrains, and medical power systems.

FAQ

What is the isolation voltage rating of SI8651BC-AS1R and which safety standards does it meet?

The SI8651BC-AS1R has a 3.75 kVRMS reinforced isolation rating and is certified to UL 1577 (1 min), VDE 0884-10, CSA Component Notice 5A, and CQC GB4943.1. These approvals validate its use in industrial equipment with working voltages up to 600 V AC/DC and ensure compliance with IEC 62368-1 and IEC 60601-1 for medical-grade isolation barriers. SI8651BC-AS1R meets all required creepage and clearance distances for narrow-body SOIC-16 packaging.

How does the fail-safe default-low feature of SI8651BC-AS1R operate during power loss?

When VDD1 is unpowered (0 V), the SI8651BC-AS1R outputs (B1–B4 and A5) default to logic low while VDD2 remains powered-this is factory-configured via ordering code "C" in SI8651BC-AS1R. This behavior prevents unintended activation of downstream power switches during brownout or primary-side failure. The SI8651BC-AS1R returns to normal operation within 1 μs after VDD1 rises above UVLO+ (2.24 V typical).

Can SI8651BC-AS1R support mixed 2.5 V and 5 V supply domains on its two sides?

Yes, SI8651BC-AS1R supports independent 2.5–5.5 V supplies on VDD1 and VDD2 sides. For example, VDD1 can be 2.5 V to interface with low-voltage FPGAs while VDD2 runs at 5 V to drive legacy optocoupler-replacement loads. Input thresholds (VT+ = 1.67 V typ, VT– = 1.23 V typ) and output drive strength (VOH = VDD–0.4 V) remain valid across this full range, and the SI8651BC-AS1R maintains 150 Mbps performance at both extremes.

What is the function of EN1 and EN2 pins on SI8651BC-AS1R, and how are they biased?

EN1 controls tri-state of output A5 (Side A); EN2 controls tri-state of outputs B1–B4 (Side B). Both are active-high, internally pulled up to their respective VDD (2 μA current source), and tolerate floating states-but Skyworks recommends tying unused enables to VDD or GND in noisy environments. When EN1 = L, A5 enters high-impedance; when EN2 = L, B1–B4 enter high-impedance. SI8651BC-AS1R retains fail-safe default-low behavior even during tri-state operation.

Does SI8651BC-AS1R require external components for reliable operation?

SI8651BC-AS1R requires only two 0.1 μF ceramic bypass capacitors: one between VDD1 and GND1, and another between VDD2 and GND2, placed adjacent to the SOIC-16 pads. No pull-up/down resistors are needed-the SI8651BC-AS1R integrates Schmitt-trigger inputs and fail-safe biasing. External series resistors (50–300 Ω) on inputs/outputs are optional and recommended only in extremely noisy environments to damp ringing.