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Skyworks Solutions Inc. SI8661BB-AU
- Part No.:
- SI8661BB-AU
- Manufacturer:
- Skyworks Solutions Inc.
- Category:
- Digital Isolators
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
SI8661BB-AU.pdf
- Description:
- AUTOMOTIVE 2.5 KV 5 FORWARD & 1
- Quantity:
- Payment:
- Shipping:
Inventory:4,137
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Product details
Overview
SI8661BB-AU from Skyworks is a six-channel automotive-grade digital isolator with 5 input channels on VDD1 side and 1 output channel on VDD2 side, supporting up to 150 Mbps data rate, <10 ns propagation delay, and 2.5 kVRMS isolation rating in QSOP-16 package. It operates from 2.5–5.5 V supply, features Schmitt-trigger inputs, selectable fail-safe low-default output, and is AEC-Q100 qualified for battery management systems.
For engineers reviewing the SI8661BB-AU datasheet, SI8661BB-AU pinout, SI8661BB-AU application, or SI8661BB-AU equivalent, this page delivers verified electrical specs, automotive-grade timing performance, fail-safe configuration details, and real-world isolation use cases in high-noise power electronics and EV subsystems.
Technical Context
The SI8661BB-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 undervoltage lockout (UVLO) on both sides, with VDDUV+ = 2.24 V (typ) and hysteresis of 70 mV (typ).
It delivers precise timing with 0.5 ns typical channel-channel skew and 2 ns propagation delay skew, while maintaining 50 kV/µs common-mode transient immunity (CMTI) at 1500 V common-mode voltage. The device uses internal 50 Ω output impedance drivers compatible with controlled-impedance PCB routing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Max Data Rate | 150 Mbps - supports high-speed serial interfaces like SPI, RS-485 transceiver control, and isolated ADC/DAC sampling clocks. |
| Propagation Delay | 8.0 ns (typ) - enables sub-10 ns timing-critical signal isolation in motor gate drivers and real-time BMS fault reporting. |
| Isolation Rating | 2.5 kVRMS - certified to UL 1577, VDE 0884-10, and IEC 62368-1 for reinforced insulation in industrial and automotive end equipment. |
| Supply Voltage Range | 2.5–5.5 V - allows direct interfacing with 3.3 V microcontrollers and 5 V logic without level-shifting. |
| Fail-Safe Default | Low output - ensures safe shutdown state during input-side power loss in traction inverter enable circuits. |
| Operating Temperature | –40 to +125 °C - meets AEC-Q100 Grade 0 requirements for under-hood and battery-pack environments. |
| CMTI | 50 kV/µs (typ) - prevents data corruption during fast-switching events in SiC/GaN power stages. |
Pinout & Package
SI8661BB-AU is housed in a RoHS-compliant QSOP-16 package (5.3 mm × 10.2 mm, 1.0 mm height) with 0.635 mm lead pitch and 8 mm creepage distance. Pin functions are validated per Skyworks datasheet Section 5 (Pin Descriptions) and Table 5.1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD1 | Input-side power supply | Supplies 2.5–5.5 V to input-side logic and RF transmitter; requires 0.1 µF bypass capacitor. |
| GND1 | Input-side ground reference | Return path for VDD1; must be separated from GND2 by ≥8 mm creepage for reinforced insulation compliance. |
| IN1–IN5 | Digital input signals (side A) | Schmitt-trigger inputs tolerate slow edges and reject >0.44 V hysteresis noise; accept 0–VDD1 logic levels. |
| VDD2 | Output-side power supply | Supplies 2.5–5.5 V to output-side receiver and driver; independent of VDD1 for galvanic isolation. |
| GND2 | Output-side ground reference | Return path for VDD2; forms isolated domain boundary with GND1 across semiconductor barrier. |
| OUT1 | Isolated digital output (side B) | 50 Ω nominal output impedance; drives 15 pF loads directly; defaults low during VDD1 undervoltage. |
| NC | No-connect pins (pins 8, 9, 15, 16) | Internally unused; must remain unconnected per datasheet to avoid parasitic coupling or certification failure. |
Key Features
| Feature | Design Value |
|---|---|
| RF-based isolation barrier | Eliminates LED aging and temperature drift; maintains stable propagation delay and CMTI over 60-year lifetime at rated voltage. |
| Selectably fail-safe output | Factory-configured low-default state ensures safe deactivation of downstream power stages during input-side brownout. |
| Ultra-low power at 100 Mbps | 8.8 mA (typ) on VDD1 and 23 mA (typ) on VDD2 at 5 V - reduces thermal load in compact battery modules. |
| Automotive qualification | AEC-Q100 Grade 0, AIAG-compliant PPAP, IMDS/CAMDS listing - supports Tier-1 BMS and OBC qualification workflows. |
| High-noise immunity | 35–50 kV/µs CMTI and 0.5 ns channel skew - preserves signal integrity in 100+ kHz switching inverters with dV/dt >50 V/ns. |
Applications
| Battery Management System (BMS) | Traction Inverter Control |
|---|---|
Use Scenario: Isolating cell voltage monitoring ADC signals and pack contactor control commands between high-voltage battery stack and low-voltage MCU domain. IC Role / Device Role / Timing Role: SI8661BB-AU transmits five analog monitor enable signals (IN1–IN5) and receives one isolated fault flag (OUT1) with <10 ns latency. Use Value: Enables simultaneous sampling of 5 cell groups while guaranteeing fail-safe open-contact behavior during MCU reset or VDD1 dropout. |
Use Scenario: Transmitting PWM enable/disable commands from MCU to isolated gate drivers in 800 V SiC inverter half-bridges. IC Role / Device Role / Timing Role: SI8661BB-AU carries five independent gate-enable signals across isolation barrier with <2.5 ns inter-channel skew. Use Value: Prevents shoot-through by ensuring matched timing across all phase legs, even under fast dv/dt transients exceeding 30 kV/µs. |
| On-Board Charger (OBC) | Charging Station Communication |
Use Scenario: Isolating digital control signals between AC/DC PFC stage and DC/DC LLC converter in bidirectional OBC topologies. IC Role / Device Role / Timing Role: SI8661BB-AU routes five feedback loop commands (e.g., voltage reference, current limit, soft-start) from primary to secondary side. Use Value: Maintains closed-loop stability at 150 Mbps with sub-10 ns jitter, avoiding phase margin erosion in high-bandwidth regulation loops. |
Use Scenario: Isolating CAN FD communication lines and safety interlock status between charging station controller and vehicle inlet. IC Role / Device Role / Timing Role: SI8661BB-AU isolates five CAN TX/RX pairs and one hardware fault signal (e.g., overtemperature latch) across 2.5 kVRMS barrier. Use Value: Meets IEC 62196 and ISO 15118 requirements for reinforced insulation while preserving CAN FD bit timing at 2 Mbps. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar digital isolator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SI8661BB-B-IU | Industrial-grade (–I suffix), same pinout, identical electrical specs, but lacks AEC-Q100 qualification and PPAP documentation. | Approved for non-automotive industrial automation only; not suitable for OEM automotive BMS or OBC programs. | Select SI8661BB-B-IU only for cost-sensitive industrial designs where automotive traceability and zero-defect manufacturing are not required. |
| ADUM6601ARWZ | 6-channel isolator with integrated 5 V iso-power; higher 12 ns max propagation delay; 3.75 kVRMS rating; SOIC-16WB package. | Used where isolated power is needed alongside signal isolation; larger footprint and higher quiescent current (20 mA @ 1 Mbps). | Choose ADUM6601ARWZ when board space permits wider SOIC and auxiliary isolated supply simplifies system architecture. |
Compared with SI8661BB-B-IU, the SI8661BB-AU adds automotive process controls and PPAP support without sacrificing speed or power; versus ADUM6601ARWZ, it trades integrated power for lower propagation delay, smaller QSOP footprint, and optimized current draw in high-data-rate BMS links.
Availability
SI8661BB-AU is available at Aetrix Electronics and suitable for battery management systems, traction inverters, on-board chargers, and charging station controllers requiring stable component supply with automotive-grade traceability and long-term lifecycle assurance.
Supply support for SI8661BB-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 Si866x family was designed specifically for high-reliability automotive and industrial isolation applications demanding ultra-low power, precise timing, and reinforced safety certification-enabling next-generation EV power electronics and smart grid infrastructure.
FAQ
What is the default output state of the SI8661BB-AU during input-side power loss?
The SI8661BB-AU is configured with a factory-set fail-safe low-default output. When VDD1 drops below UVLO threshold (2.16 V typ), OUT1 transitions to and holds logic low while VDD2 remains powered-ensuring safe deactivation of downstream circuits such as gate drivers or contactors. This behavior is confirmed in Table 3.1 and Ordering Guide footnote 6 of the Si8660/61/62/63 datasheet.
Does the SI8661BB-AU require external components for basic operation?
Yes-the SI8661BB-AU requires two 0.1 µF ceramic bypass capacitors: one between VDD1 and GND1, and another between VDD2 and GND2, placed within 3 mm of their respective pins. No pull-up/pull-down resistors are needed, as Schmitt-trigger inputs and fail-safe configuration are implemented internally. These requirements are specified in Section 3.3.1 and Figure 3.1 of the datasheet.
Can the SI8661BB-AU interface directly with a 3.3 V microcontroller and a 5 V gate driver?
Yes-SI8661BB-AU supports independent 2.5–5.5 V supplies on both sides. VDD1 can be set to 3.3 V for MCU-side logic compatibility, while VDD2 can be set to 5 V to drive gate drivers with sufficient VOH (>4.6 V) and VOL (<0.4 V). Input thresholds (VT+ = 1.67 V typ, VT– = 1.23 V typ) ensure reliable recognition of 3.3 V logic levels on IN1–IN5.
What safety certifications apply to the SI8661BB-AU?
The SI8661BB-AU is certified to UL 1577 (5000 VRMS, 1 min), VDE 0884-10 (reinforced insulation), CSA Component Acceptance Notice 5A, and IEC 62368-1/60950-1/60601-1. All certifications cover its 2.5 kVRMS rating in QSOP-16 package. Certification reports are accessible via Skyworks' compliance portal using the part number SI8661BB-AU.
How does the SI8661BB-AU achieve 50 kV/µs common-mode transient immunity?
The SI8661BB-AU achieves 50 kV/µs CMTI through its RF-modulated isolation architecture and differential RF receiver design, which rejects fast common-mode transients induced by high-dV/dt switching in SiC/GaN inverters. This performance is measured per Figure 4.2 test circuit at VCM = 1500 V and is guaranteed across –40 to +125 °C per Table 4.2.
SI8661BB-AU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Skyworks Solutions Inc.
- Series:
- -
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Technology:
- Capacitive Coupling
- Type:
- General Purpose
- Isolated Power:
- Yes
- Number of Channels:
- 6
- Inputs - Side 1/Side 2:
- 5/1
- Channel Type:
- Unidirectional
- Voltage - Isolation:
- 2500Vrms
- Common Mode Transient Immunity (Min):
- 35kV/µs
- Data Rate:
- 150Mbps
- Propagation Delay tpLH / tpHL (Max):
- 13ns, 13ns
- Pulse Width Distortion (Max):
- 4.5ns
- Rise / Fall Time (Typ):
- 2.5ns, 2.5ns
- Voltage - Supply:
- 2.375V ~ 5.5V
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QSOP
SI8661BB-AU FAQ
1.How can I place an order for SI8661BB-AU through Aetrix?
Please submit a Request for Quotation (RFQ) for SI8661BB-AU on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SI8661BB-AU reliable?
The price and inventory of SI8661BB-AU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI8661BB-AU is usually 5 days.
3.What payment methods are accepted for SI8661BB-AU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI8661BB-AU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SI8661BB-AU?
SI8661BB-AU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SI8661BB-AU order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SI8661BB-AU?
For technical support, including SI8661BB-AU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI8661BB-AU requirements.
6.How does Aetrix verify that SI8661BB-AU is sourced from the original manufacturer or authorized distributors?
All SI8661BB-AU products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SI8661BB-AU meets industry standards.
7.What is the process for return or replacement of SI8661BB-AU?
All SI8661BB-AU units undergo pre-shipment inspection (PSI). If there is an issue with SI8661BB-AU, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SI8661BB-AU part is unused and in its original packaging.
Return procedure for SI8661BB-AU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SI8661BB-AU Tags
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ISO1212DBQR
Texas Instruments
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ISO6721BDR
Texas Instruments
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SI8710AC-B-ISR
Skyworks Solutions Inc.
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ISO7720FDR
Texas Instruments
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ISO7721DR
Texas Instruments
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ISO7721FDR
Texas Instruments
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SI8710CC-B-ISR
Skyworks Solutions Inc.
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ISO6741FQDWRQ1
Texas Instruments
-
ISO7721DWVR
Texas Instruments
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ISO7762FDBQR
Texas Instruments
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ISO7741DWR
Texas Instruments
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ISO7741FDWR
Texas Instruments
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