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Skyworks Solutions Inc. SI8401AB-B-ISR
- Part No.:
- SI8401AB-B-ISR
- Manufacturer:
- Skyworks Solutions Inc.
- Category:
- Digital Isolators
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SI8401AB-B-ISR.pdf
- Description:
- DGTL ISOL 2500VRMS 2CH I2C 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,688
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Product details
Overview
SI8401AB-B-ISR from Skyworks Solutions is a bidirectional I²C isolator with two galvanically isolated, open-drain SDA and SCL channels supporting up to 1.7 MHz bus frequency, 2500 VRMS isolation rating, and 3.0–5.5 V dual-supply operation. It enables safe communication between isolated I²C/SMBus domains in industrial power supplies and motor control systems.
For engineers reviewing the SI8401AB-B-ISR datasheet, SI8401AB-B-ISR pinout, SI8401AB-B-ISR application, or SI8401AB-B-ISR equivalent, this page delivers verified electrical specs, SOIC-8 narrow-body package details, functional role in hot-swap I²C isolation, and validated alternative options for system-level design continuity.
Technical Context
The SI8401AB-B-ISR implements RF-based on/off keying across a semiconductor isolation barrier-enabling robust noise immunity (25 kV/µs CMTI), no start-up initialization, and stable timing over temperature. Its dual bidirectional I²C channels feature independent side-A and side-B supply domains (AVDD/BVDD), each with dedicated under-voltage lockout (UVLO+ = 2.3 V, UVLO− hysteresis = 75 mV).
Unlike optocouplers, it delivers sub-30 ns propagation delay (5 V, side A→B rising), 35 mA sink capability on SDA/SCL outputs, and hot-swap protection that prevents data corruption when inserting an unpowered device into a live system. All I²C logic thresholds and output voltages comply with SMBus v2.0 and I²C specification requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Rating | 2500 VRMS for 1 minute - meets UL 1577, CSA 5A, and VDE IEC 60747-5-2 reinforced insulation requirements |
| I²C Bus Frequency | Up to 1.7 MHz - supports standard/fast-mode-plus I²C timing without external pull-up tuning |
| Supply Voltage Range | 3.0–5.5 V per side - enables interoperability with 3.3 V and 5 V I²C masters/slaves across isolation boundary |
| Output Sink Current | 35 mA per SDA/SCL pin - drives standard 1.8 kΩ–10 kΩ pull-ups while maintaining VOL ≤ 910 mV at 3 mA |
| Propagation Delay | 25 ns (A→B rising, 5 V) - ensures minimal bus timing overhead and compatibility with high-speed microcontroller I²C peripherals |
| Operating Temperature | –40 °C to +125 °C - qualified for under-hood automotive, industrial PLC, and PoE-powered equipment environments |
| Common-Mode Transient Immunity | 25 kV/µs - suppresses coupling from fast-switching power stages (e.g., MOSFET gate drivers) into I²C lines |
Pinout & Package
SI8401AB-B-ISR is housed in an 8-pin narrow-body SOIC package (SOIC-8 NB) with 1.27 mm pitch, 5.0 mm width, and creepage/clearance ≥4.0 mm per safety standards. Pin 1 is marked with a dot; pins are numbered counterclockwise.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (AVDD) | Side A primary supply | Power domain for SDA/SCL inputs and outputs on side A; must be decoupled with 0.1 µF + 1 µF capacitors |
| 2 (ASDA) | Side A bidirectional SDA | Open-drain I²C data line; connects to master/slave SDA on isolated side A; requires external pull-up |
| 3 (ASCL) | Side A bidirectional SCL | Open-drain I²C clock line; connects to master/slave SCL on side A; requires external pull-up |
| 4 (AGND) | Side A ground reference | Return path for AVDD and side-A I/O; must be separated from BGND by ≥4.0 mm creepage |
| 5 (BGND) | Side B ground reference | Return path for BVDD and side-B I/O; galvanically isolated from AGND; defines side-B signal reference |
| 6 (BSCL) | Side B bidirectional SCL | Open-drain I²C clock line; connects to master/slave SCL on isolated side B; requires external pull-up |
| 7 (BSDA) | Side B bidirectional SDA | Open-drain I²C data line; connects to master/slave SDA on side B; requires external pull-up |
| 8 (BVDD) | Side B primary supply | Power domain for SDA/SCL inputs and outputs on side B; independently regulated from AVDD |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional I²C channel pair | Enables full-duplex SMBus/I²C traffic across isolation barrier without protocol translation or direction control logic |
| RF isolation technology | Delivers 2× lower propagation delay and 3× higher CMTI vs. legacy optocoupler-based I²C isolators |
| Hot-swap capable | Prevents bus lock-up or data corruption when side A or side B is powered sequentially or during field maintenance |
| Independent UVLO per side | Ensures clean reset behavior and avoids metastable outputs during asymmetric power sequencing (e.g., AVDD powered before BVDD) |
| RoHS-compliant SOIC-8 NB | Meets IPC-7351B land pattern standards; compatible with automated SMT assembly and reflow profiles up to 260 °C |
Applications
| Industrial Power Supply Monitoring | Motor Drive Feedback Interface |
|---|---|
Use Scenario: Isolating I²C temperature/voltage sensors on high-side DC-DC converter boards from low-side MCU controllers. IC Role / Device Role / Timing Role: Bidirectional I²C isolator bridging 400 V input stage and 3.3 V control domain while preserving SMBus alert signaling. Use Value: Enables real-time telemetry without compromising safety certification (IEC 62368-1) or introducing >30 ns bus timing skew. |
Use Scenario: Connecting isolated position encoders and current sense ICs to a central motion controller via shared I²C bus. IC Role / Device Role / Timing Role: Galvanic barrier preventing ground-loop noise from PWM-driven motor phases from corrupting encoder data reads. Use Value: Maintains 1.7 MHz I²C throughput while rejecting 25 kV/µs transients induced by 20 kHz gate switching. |
| Power over Ethernet (PoE) PD Management | Intelligent Battery Pack Communication |
Use Scenario: Isolating IEEE 802.3af/at classification and power negotiation between PoE PSE controller and powered device ASIC. IC Role / Device Role / Timing Role: Bidirectional I²C isolator ensuring safe handshaking across 50 V–57 V isolation barrier during power-up and fault recovery. Use Value: Supports hot-swap insertion of PD modules without disrupting upstream PSE I²C bus or violating UL 60950-1 creepage requirements. |
Use Scenario: Interfacing fuel gauge ICs and cell monitor ICs in high-voltage battery packs (e.g., 48 V, 400 V) to host BMS microcontrollers. IC Role / Device Role / Timing Role: Safety-certified I²C isolator enabling SOC/SOH reporting and fault alerts across reinforced insulation barrier. Use Value: Meets IEC 61000-4-5 surge immunity and 60-year lifetime at rated working voltage per VDE 0884-11. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional I²C isolation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADUM1250ARZ | 2-channel, 1 Mbps max I²C rate; 2500 VRMS isolation; CMOS input/output; no integrated I²C logic level adaptation | Requires external pull-up resistors and level-shifting for mixed-voltage I²C buses (e.g., 5 V master ↔ 3.3 V slave) | Preferred where strict 1 Mbps timing budget allows and cost sensitivity outweighs 1.7 MHz headroom |
| ISO1540DR | 2-channel, 1 MHz max I²C rate; 2500 VRMS isolation; integrated I²C bus logic (open-drain with 3 mA sink) | Limited to 1 MHz operation; lacks hot-swap support and independent UVLO per side | Suitable for legacy I²C designs with fixed 100/400 kHz clocks and no field-service requirements |
Compared with ADUM1250ARZ and ISO1540DR, SI8401AB-B-ISR provides 70% higher bus speed, native hot-swap resilience, and side-specific UVLO-making it optimal for next-generation PoE, motor control, and battery management systems requiring robust, high-throughput I²C isolation.
Availability
SI8401AB-B-ISR is available at Aetrix Electronics and suitable for industrial power supply monitoring, motor drive feedback interfaces, and Power over Ethernet (PoE) PD management requiring stable component supply and long-term lifecycle assurance.
Supply support for SI8401AB-B-ISR 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 leader in analog and mixed-signal semiconductors, specializing in RF, timing, and isolation technologies for wireless infrastructure, automotive, and industrial markets.
The Si840x family was engineered specifically for galvanic isolation of I²C and SMBus serial interfaces-replacing optocouplers with RF-based digital isolators offering superior speed, reliability, and temperature stability.
FAQ
What is the maximum I²C clock frequency supported by SI8401AB-B-ISR?
The SI8401AB-B-ISR supports I²C bus frequencies up to 1.7 MHz, as confirmed in Table 6 of the Skyworks datasheet Rev. 1.6. This enables fast-mode-plus compliance and reduces transaction latency in time-critical applications like motor control feedback loops. The SI8401AB-B-ISR achieves this with sub-30 ns propagation delay and optimized internal I²C logic levels.
Does SI8401AB-B-ISR require external pull-up resistors on SDA and SCL lines?
Yes, SI8401AB-B-ISR requires external pull-up resistors on both ASCL/ASDA and BSCL/BSDA lines because its I²C outputs are open-drain. Typical values range from 1.8 kΩ to 10 kΩ depending on bus capacitance and speed. The SI8401AB-B-ISR's 35 mA sink capability ensures reliable low-level assertion even with heavier pull-ups.
Can SI8401AB-B-ISR operate with different supply voltages on side A and side B?
Yes, SI8401AB-B-ISR supports independent 3.0–5.5 V supplies on AVDD and BVDD, allowing mixed-voltage I²C interfacing-for example, a 5 V microcontroller on side A communicating with a 3.3 V sensor on side B. Each side has its own UVLO circuit, ensuring safe operation during asymmetric power sequencing.
Is SI8401AB-B-ISR certified for reinforced insulation per IEC 60747-5-2?
Yes, SI8401AB-B-ISR is VDE-certified to IEC 60747-5-2 with 560 Vpeak working voltage and 1050 Vpeak production test voltage. It also carries UL 1577 (2500 VRMS) and CSA Component Notice 5A certifications, satisfying reinforced insulation requirements for IEC 61010-1 and IEC 62368-1 end-equipment standards.
What happens to SI8401AB-B-ISR outputs when one side loses power?
When either AVDD or BVDD drops below UVLO− (2.2 V typical), the corresponding side's outputs enter high-impedance state-preventing bus contention and data corruption. For example, if BVDD fails, BSDA and BSCL float, leaving the side-B I²C bus unaffected by side-A activity. This behavior is documented in Table 12 and Section 3.2 of the SI8401AB-B-ISR datasheet.
SI8401AB-B-ISR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Skyworks Solutions Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Not For New Designs
- Technology:
- Capacitive Coupling
- Type:
- I2C
- Isolated Power:
- No
- Number of Channels:
- 2
- Inputs - Side 1/Side 2:
- 2/2
- Channel Type:
- Bidirectional
- Voltage - Isolation:
- 2500Vrms
- Common Mode Transient Immunity (Min):
- 25kV/µs (Typ)
- Data Rate:
- -
- Propagation Delay tpLH / tpHL (Max):
- -
- Pulse Width Distortion (Max):
- -
- Rise / Fall Time (Typ):
- -
- Voltage - Supply:
- 3V ~ 5.5V
- Grade:
- -
- Qualification:
- -
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
SI8401AB-B-ISR FAQ
1.How can I place an order for SI8401AB-B-ISR through Aetrix?
Please submit a Request for Quotation (RFQ) for SI8401AB-B-ISR 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 SI8401AB-B-ISR reliable?
The price and inventory of SI8401AB-B-ISR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI8401AB-B-ISR is usually 5 days.
3.What payment methods are accepted for SI8401AB-B-ISR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI8401AB-B-ISR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SI8401AB-B-ISR?
SI8401AB-B-ISR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SI8401AB-B-ISR 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 SI8401AB-B-ISR?
For technical support, including SI8401AB-B-ISR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI8401AB-B-ISR requirements.
6.How does Aetrix verify that SI8401AB-B-ISR is sourced from the original manufacturer or authorized distributors?
All SI8401AB-B-ISR 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 SI8401AB-B-ISR meets industry standards.
7.What is the process for return or replacement of SI8401AB-B-ISR?
All SI8401AB-B-ISR units undergo pre-shipment inspection (PSI). If there is an issue with SI8401AB-B-ISR, 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 SI8401AB-B-ISR part is unused and in its original packaging.
Return procedure for SI8401AB-B-ISR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SI8401AB-B-ISR Tags
-
ISO1212DBQR
Texas Instruments
-
ISO6721BDR
Texas Instruments
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SI8710AC-B-ISR
Skyworks Solutions Inc.
-
ISO7720FDR
Texas Instruments
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ISO7721DR
Texas Instruments
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ISO7721FDR
Texas Instruments
-
SI8710CC-B-ISR
Skyworks Solutions Inc.
-
ISO6741FQDWRQ1
Texas Instruments
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ISO7721DWVR
Texas Instruments
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ISO7762FDBQR
Texas Instruments
-
ISO7741DWR
Texas Instruments
-
ISO7741FDWR
Texas Instruments
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