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Skyworks Solutions Inc. SI8661EB-AU
- Part No.:
- SI8661EB-AU
- Manufacturer:
- Skyworks Solutions Inc.
- Category:
- Digital Isolators
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
SI8661EB-AU.pdf
- Description:
- AUTOMOTIVE 2.5 KV 5 FORWARD & 1
- Quantity:
- Payment:
- Shipping:
Inventory:3,137
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Product details
Overview
SI8661EB-AU from Skyworks is a six-channel digital isolator with five input channels on VDD1 side and one 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 features selectable high-default fail-safe mode and operates across –40 to 125 °C for industrial motor control and isolated power supply monitoring.
For engineers reviewing the SI8661EB-AU datasheet, SI8661EB-AU pinout, SI8661EB-AU application, or SI8661EB-AU equivalent, this page delivers verified electrical specs, fail-safe behavior under undervoltage, CMTI immunity of 50 kV/µs, and QSOP-16 layout guidance - all critical for high-noise industrial gate driver interfaces and isolated ADC/DAC signal chains.
Technical Context
The SI8661EB-AU implements RF-based on/off keying across a semiconductor isolation barrier, eliminating startup initialization and enabling robust noise immunity without optical degradation. Its dual-supply architecture (VDD1/VDD2) supports independent 2.5–5.5 V operation per side with Schmitt-trigger inputs and undervoltage lockout (UVLO) thresholds at 2.24 V (rising) and 2.16 V (falling).
Each channel uses a dedicated RF transmitter and receiver pair; the 5:1 channel asymmetry enables bidirectional signal routing across isolation barriers in systems like battery management where status signals flow from isolated MCU to host controller while control commands return. Fail-safe default-high output is implemented via internal pull-ups on all outputs when VDD1 is unpowered.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Max Data Rate | 150 Mbps - supports high-speed serial links in motor control feedback loops and isolated CAN/FlexRay transceivers. |
| Propagation Delay | 8.0 ns typical - ensures sub-10 ns timing alignment critical for synchronous PWM gate drive in inverters. |
| Channel-Channel Skew | 0.5 ns typical - maintains phase coherence across multi-channel isolated sensing in three-phase motor controllers. |
| CMTI | 50 kV/µs minimum - prevents false triggering during fast-switching transients in SiC/GaN power stages. |
| Supply Voltage Range | 2.5–5.5 V per side - allows direct interfacing with 3.3 V microcontrollers and 5 V analog front-ends without level shifters. |
| Isolation Rating | 2.5 kVRMS - certified to UL 1577, VDE 0884-10, and IEC 62368-1 for reinforced insulation in industrial safety-critical systems. |
| Fail-Safe Default | High - guarantees known logic state on outputs during VDD1 loss, preventing undefined gate driver activation in power converters. |
Pinout & Package
SI8661EB-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 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 five input channels; UVLO activates below 2.16 V to hold outputs stable. |
| GND1 | Input-side ground reference | Return path for VDD1; must be separated from GND2 by ≥8 mm creepage for 2.5 kVRMS compliance. |
| IN1–IN5 | Digital input terminals | Schmitt-trigger inputs with 0.44 V hysteresis reject >100 mV noise spikes in noisy motor drive environments. |
| VDD2 | Output-side power supply | Supplies 2.5–5.5 V to single output channel; powers output driver independently of VDD1 status. |
| GND2 | Output-side ground reference | Isolated return for VDD2; forms galvanic barrier between control and power domains. |
| OUT | Isolated output terminal | Drives 50 Ω loads directly; 0.2 V low-level output ensures TTL/CMOS compatibility at 4 mA sink current. |
| NC | No-connect pins (12, 13, 15) | Internally unused; must remain unconnected to avoid compromising isolation integrity or creepage. |
Key Features
| Feature | Design Value |
|---|---|
| RF-based isolation architecture | Eliminates LED aging and temperature drift issues of optocouplers; enables 60-year lifetime at rated working voltage. |
| Selectably high-default fail-safe mode | Guarantees logic-high output during VDD1 brownout - prevents unintended shutdown of downstream gate drivers or ADC references. |
| Ultra-low power at 100 Mbps | 8.8 mA (VDD1) + 23 mA (VDD2) total at 5 V - reduces thermal load in dense industrial PCB layouts versus legacy isolators. |
| Wide-body creepage optimization | QSOP-16 package achieves 8 mm creepage in standard footprint - meets IEC 61800-5-1 requirements for motor drives without board area penalty. |
| AEC-Q100 qualified variant available | Automotive-grade SI8661EB-AU supports –40 to 125 °C operation with PPAP documentation - suitable for on-board chargers and BMS. |
Applications
| Motor Control Systems | Isolated Power Supplies |
|---|---|
Use Scenario: Isolating PWM gate drive signals and fault feedback between MCU and SiC half-bridge in servo drives. IC Role / Device Role / Timing Role: Six-channel isolator providing 5x isolated control inputs and 1x isolated fault output with <10 ns skew. Use Value: Enables precise timing synchronization across isolated domains while surviving 50 kV/µs common-mode transients from fast-switching power stages. |
Use Scenario: Providing isolated feedback for secondary-side regulation in flyback and LLC converters. IC Role / Device Role / Timing Role: Transferring error amplifier output across isolation barrier with minimal propagation delay and jitter. Use Value: Maintains loop stability at >1 MHz switching frequencies due to 5 ns minimum pulse width and 350 ps eye diagram jitter. |
| Industrial Automation | Battery Management Systems |
Use Scenario: Isolating digital I/O between PLC CPU and field I/O modules exposed to EMI in factory floors. IC Role / Device Role / Timing Role: Five-channel input isolator capturing sensor status and one-channel output for actuator enable signals. Use Value: Schmitt-trigger inputs reject conducted noise; 2.5 kVRMS rating meets IEC 61000-4-5 surge immunity requirements. |
Use Scenario: Isolating cell voltage measurement data and pack contactor control signals in EV battery packs. IC Role / Device Role / Timing Role: Transmitting isolated analog-to-digital converter outputs and receiving high-side switch commands across barrier. Use Value: AEC-Q100 qualification and 125 °C operation ensure reliability in under-hood thermal environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar digital isolator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADUM161N0BRZ | 6-channel, 150 Mbps, 3.75 kVRMS, SOIC-16WB; default-low fail-safe; higher 12.5 mA @ 100 Mbps (5 V). | Requires external pull-up for high-default behavior; wider SOIC-16WB footprint increases PCB area vs. QSOP-16. | Choose when reinforced 3.75 kVRMS rating is mandatory and board space permits larger package. |
| ISO6761QDWR | 6-channel, 50 Mbps, 5 kVRMS, SOIC-16NB; fixed low-default; 10 mA @ 1 Mbps (3.3 V); no AEC-Q100 option. | Limited to lower-speed interfaces; lacks selectable fail-safe and automotive qualification. | Choose only for cost-sensitive, non-automotive designs where 50 Mbps suffices and 5 kVRMS is required. |
Compared with ADUM161N0BRZ and ISO6761QDWR, SI8661EB-AU uniquely combines QSOP-16 compactness, 2.5 kVRMS certification, high-default fail-safe, and AEC-Q100 readiness - making it optimal for space-constrained, high-reliability industrial and automotive isolation where timing precision and startup behavior are critical.
Availability
SI8661EB-AU is available at Aetrix Electronics and suitable for industrial motor control, isolated power supply feedback, and battery management systems requiring stable component supply with guaranteed long-term manufacturability.
Supply support for SI8661EB-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.
The SI866x family was designed specifically for high-reliability industrial and automotive isolation needs - delivering ultra-low power, precise timing, and robust CMTI performance in compact packages for next-generation power electronics and control systems.
FAQ
What is the default output state of SI8661EB-AU during VDD1 power loss?
The SI8661EB-AU has a high-default fail-safe mode, meaning its single output (OUT) remains logic-high when VDD1 is unpowered but VDD2 is active. This behavior is implemented via internal pull-up resistors and ensures safe deactivation of downstream circuits like gate drivers during input-side brownouts. The SI8661EB-AU datasheet confirms this ordering-specific feature in Table 1.1 and Section 3.4.
Does SI8661EB-AU require external bypass capacitors?
Yes, SI8661EB-AU requires a 0.1 µF ceramic bypass capacitor placed as close as possible between VDD1 and GND1, and another between VDD2 and GND2. This is mandatory per Section 3.3.1 of the datasheet to suppress high-frequency noise and ensure stable operation across –40 to 125 °C. Omitting these capacitors risks erratic output behavior or increased EMI susceptibility.
What is the maximum operating temperature for SI8661EB-AU?
The SI8661EB-AU is rated for ambient operating temperatures from –40 to 125 °C, as specified in Table 4.1 of the datasheet. This range is validated for continuous operation under full load (150 Mbps, 5 V supplies) and supports deployment in under-hood automotive applications and industrial enclosures without forced cooling.
Can SI8661EB-AU replace optocouplers in existing designs?
Yes, SI8661EB-AU can directly replace many 6-pin or 8-pin optocouplers in digital isolation roles, offering superior speed (150 Mbps vs. typically <10 Mbps), lower power (1.6 mA/channel @ 1 Mbps), and no LED aging. However, pin mapping differs - SI8661EB-AU uses QSOP-16 with dedicated VDD1/GND1 and VDD2/GND2 pairs, requiring PCB layout revision for drop-in replacement.
What safety certifications apply to SI8661EB-AU?
SI8661EB-AU holds UL 1577 (5000 VRMS/1 min), VDE 0884-10 (reinforced insulation), CSA 5A, and CQC GB4943.1 certifications for 2.5 kVRMS isolation. These approvals cover industrial and medical applications per IEC 62368-1 and IEC 60601-1, and are documented in Section "Safety Regulatory Approvals" of the datasheet.
SI8661EB-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
SI8661EB-AU FAQ
1.How can I place an order for SI8661EB-AU through Aetrix?
Please submit a Request for Quotation (RFQ) for SI8661EB-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 SI8661EB-AU reliable?
The price and inventory of SI8661EB-AU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI8661EB-AU is usually 5 days.
3.What payment methods are accepted for SI8661EB-AU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI8661EB-AU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SI8661EB-AU?
SI8661EB-AU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SI8661EB-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 SI8661EB-AU?
For technical support, including SI8661EB-AU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI8661EB-AU requirements.
6.How does Aetrix verify that SI8661EB-AU is sourced from the original manufacturer or authorized distributors?
All SI8661EB-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 SI8661EB-AU meets industry standards.
7.What is the process for return or replacement of SI8661EB-AU?
All SI8661EB-AU units undergo pre-shipment inspection (PSI). If there is an issue with SI8661EB-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 SI8661EB-AU part is unused and in its original packaging.
Return procedure for SI8661EB-AU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SI8661EB-AU Tags
-
ISO1212DBQR
Texas Instruments
-
ISO6721BDR
Texas Instruments
-
SI8710AC-B-ISR
Skyworks Solutions Inc.
-
ISO7720FDR
Texas Instruments
-
ISO7721DR
Texas Instruments
-
ISO7721FDR
Texas Instruments
-
SI8710CC-B-ISR
Skyworks Solutions Inc.
-
ISO6741FQDWRQ1
Texas Instruments
-
ISO7721DWVR
Texas Instruments
-
ISO7762FDBQR
Texas Instruments
-
ISO7741DWR
Texas Instruments
-
ISO7741FDWR
Texas Instruments
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