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Skyworks Solutions Inc. SI8400AA-A-IS

Name: SI8400AA-A-IS
Brand: Skyworks Solutions Inc.
SKU: SI8400AA-A-IS
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI8400AA-A-IS

Manufacturer:: Skyworks Solutions Inc.

Category:: Digital Isolators

Package:: 8-SOIC (0.154", 3.90mm Width)

Datasheet:: SI8400AA-A-IS.pdf

Description:: DGTL ISOL 1000VRMS 2CH I2C 8SOIC

Quantity:: RFQ Add To RFQ list

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Product details

Overview

SI8400AA-A-IS from Silicon Labs is a bidirectional I²C isolator with two galvanically isolated open-drain channels (SDA and SCL), supporting up to 1.7 MHz bus frequency, 2500 VRMS isolation rating, and 3.0–5.5 V dual supply operation. It enables safe, latch-free I²C/SMBus communication across isolated domains in PoE controllers and motor control systems.

For engineers reviewing the SI8400AA-A-IS datasheet, SI8400AA-A-IS pinout, SI8400AA-A-IS application, or SI8400AA-A-IS equivalent, this device delivers verified anti-latch bidirectional I²C isolation with open-drain outputs (35 mA sink), −40 to +125 °C operation, and UL/CSA/VDE safety certifications - critical for industrial and power system designs requiring robust ground-loop elimination.

Technical Context

The SI8400AA-A-IS implements RF-based galvanic isolation using on/off keying modulation across a semiconductor barrier, eliminating startup initialization and enabling immediate data transfer after UVLO exit (tSTART ≤ 40 µs). Its anti-latch architecture ensures stable bidirectional SDA/SCL operation without external circuitry by enforcing VOL(Side A) > VIL(Side A) - specifically 910 mV max VOL at 3 mA vs. 450–780 mV VIL thresholds.

Each side features independent under-voltage lockout (UVLO+ = 2.3 V typ, hysteresis = 75 mV), hot-swap capability, and transient immunity of 25 kV/µs. The device operates with no internal clock or configuration registers, relying solely on passive RF coupling and CMOS-level input/output logic compatible with standard I²C pull-up networks.

Key Specifications

Parameter	Value and Actual Design Meaning
Isolation Rating	2500 VRMS for 1 minute - certified per UL 1577, CSA 5A, and VDE 0884-2 for reinforced insulation in industrial environments.
I²C Bus Frequency	Up to 1.7 MHz - supports full-speed I²C and SMBus timing without clock stretching degradation.
Supply Voltage Range	3.0–5.5 V per side - enables interoperability with 3.3 V and 5 V I²C masters/slaves on both isolated domains.
Output Sink Current	35 mA per channel - drives standard I²C pull-up resistors (e.g., 1.1 kΩ @ 3.3 V) while maintaining VOL ≤ 910 mV at −40 to +125 °C.
Propagation Delay	9–29 ns (rising/falling, 3.3 V) - ensures sub-100 ns round-trip delay for real-time bus arbitration and ACK timing compliance.
Operating Temperature	−40 to +125 °C - qualified for automotive-grade ambient conditions and high-temperature power electronics enclosures.
Common-Mode Transient Immunity	25 kV/µs - prevents data corruption during fast transients common in motor drives and SMPS feedback loops.

Pinout & Package

SI8400AA-A-IS is housed in an 8-pin narrow-body SOIC package (SOIC-8 NB) with 4.9 mm clearance and 4.01 mm creepage - compliant with IEC 60664-1 for reinforced insulation at ≤300 VRMS working voltage.

Pin	Circuit Role	Design Meaning
1 (AVDD)	Side A Power Supply	3.0–5.5 V supply for input-side logic and transmitter; requires local 0.1 µF + 1 µF bypass capacitors.
2 (ASDA)	Side A Bidirectional SDA	Open-drain I²C data line - connects directly to master/slave SDA with external pull-up; supports hot-swap insertion.
3 (ASCL)	Side A Bidirectional SCL	Open-drain I²C clock line - shares anti-latch logic with ASDA to prevent bus lock during clock stretching.
4 (AGND)	Side A Ground Reference	Return path for Side A supply and signals; must be isolated from BGND by ≥4.01 mm creepage.
5 (BGND)	Side B Ground Reference	Return path for Side B supply and signals; forms isolation barrier with AGND per safety certification.
6 (BSCL)	Side B Bidirectional SCL	Isolated clock output - mirrors ASCL state with <29 ns propagation delay; maintains I²C timing integrity.
7 (BSDA)	Side B Bidirectional SDA	Isolated data output - mirrors ASDA state with anti-latch protection; sinks up to 35 mA for slave ACK pulses.
8 (BVDD)	Side B Power Supply	3.0–5.5 V supply for output-side logic and receiver; independent of AVDD for true galvanic separation.

Key Features

Feature	Design Value
Anti-latch bidirectional I²C channels	Eliminates need for external latch-prevention circuits by enforcing VOL(Side A) > VIL(Side A) - enables single-chip isolation with zero external components beyond pull-ups.
RF-based isolation technology	Delivers 3× lower propagation delay and 50% lower quiescent current vs. optocouplers - e.g., 4.2 mA total supply current at 0 Hz (3.3 V).
Hot-swap and unpowered insertion tolerance	Prevents data corruption when inserting into live systems: outputs enter Hi-Z if opposite side is unpowered, avoiding bus contention.
Integrated UVLO with hysteresis	Ensures clean power-on reset: AVDD/BVDD must exceed 2.3 V (±0.15 V) and remain above 2.15 V to sustain operation - prevents metastability during brownouts.
25 kV/µs CMTI	Rejects fast common-mode noise from motor drives and SMPS - maintains bit error rate <1e−12 under EFT/burst stress per IEC 61000-4-4.

Applications

Power over Ethernet (PoE) Controllers	Industrial Motor Control Systems
Use Scenario: Isolating I²C communication between a PoE power sourcing equipment (PSE) controller and earth-grounded system management IC. IC Role / Device Role / Timing Role: Bidirectional SDA/SCL isolator providing galvanic separation between 48 V DC power domain and low-voltage control domain. Use Value: Enables UL Class 2 compliance and eliminates ground loops without adding latency or external anti-latch circuitry - critical for IEEE 802.3af/at negotiation timing.	Use Scenario: Interfacing an isolated microcontroller to I²C temperature sensors and current monitors located on high-side gate driver boards. IC Role / Device Role / Timing Role: Safety-isolated I²C bridge maintaining signal integrity across 1000 V potential differences in three-phase inverter stacks. Use Value: Supports 1.7 MHz bus speed to read sensor data within tight PWM dead-time windows - avoids timing violations in closed-loop current control.
Intelligent Power Supply Monitoring	Isolated SMPS with PMBus Interface
Use Scenario: Monitoring rail voltages and fault status in telecom rectifiers where primary-side telemetry must be isolated from secondary-side host MCU. IC Role / Device Role / Timing Role: Dual-channel I²C isolator enabling real-time PMBus read/write access to digital power controllers (e.g., TI UCD92xx) across isolation barrier. Use Value: Delivers 2500 VRMS isolation with 125 °C operation - sustains reliability in high-temperature rectifier enclosures while preserving PMBus command-response timing.	Use Scenario: Connecting a non-isolated host processor to a digitally controlled isolated DC/DC converter via PMBus for configuration and telemetry. IC Role / Device Role / Timing Role: Galvanically isolated I²C transceiver supporting PMBus packet framing, CRC validation, and write-protection commands across safety boundary. Use Value: Maintains VOL ≤ 910 mV at 35 mA sink to ensure valid logic-low levels for PMBus STOP condition detection - preventing bus hang during firmware updates.

Power over Ethernet (PoE) Controllers

Industrial Motor Control Systems

Use Scenario: Isolating I²C communication between a PoE power sourcing equipment (PSE) controller and earth-grounded system management IC.

IC Role / Device Role / Timing Role: Bidirectional SDA/SCL isolator providing galvanic separation between 48 V DC power domain and low-voltage control domain.

Use Value: Enables UL Class 2 compliance and eliminates ground loops without adding latency or external anti-latch circuitry - critical for IEEE 802.3af/at negotiation timing.

Use Scenario: Interfacing an isolated microcontroller to I²C temperature sensors and current monitors located on high-side gate driver boards.

IC Role / Device Role / Timing Role: Safety-isolated I²C bridge maintaining signal integrity across 1000 V potential differences in three-phase inverter stacks.

Use Value: Supports 1.7 MHz bus speed to read sensor data within tight PWM dead-time windows - avoids timing violations in closed-loop current control.

Intelligent Power Supply Monitoring

Isolated SMPS with PMBus Interface

Use Scenario: Monitoring rail voltages and fault status in telecom rectifiers where primary-side telemetry must be isolated from secondary-side host MCU.

IC Role / Device Role / Timing Role: Dual-channel I²C isolator enabling real-time PMBus read/write access to digital power controllers (e.g., TI UCD92xx) across isolation barrier.

Use Value: Delivers 2500 VRMS isolation with 125 °C operation - sustains reliability in high-temperature rectifier enclosures while preserving PMBus command-response timing.

Use Scenario: Connecting a non-isolated host processor to a digitally controlled isolated DC/DC converter via PMBus for configuration and telemetry.

IC Role / Device Role / Timing Role: Galvanically isolated I²C transceiver supporting PMBus packet framing, CRC validation, and write-protection commands across safety boundary.

Use Value: Maintains VOL ≤ 910 mV at 35 mA sink to ensure valid logic-low levels for PMBus STOP condition detection - preventing bus hang during firmware updates.

Equivalent & Alternatives

The following parts are listed as comparable options for similar I²C isolation applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ADUM1250ARZ	2-channel, 1 Mbps max I²C speed; 2500 VRMS isolation; 3.0–5.5 V supply; uses iCoupler® magnetic isolation.	Limited to 1 Mbps - insufficient for 1.7 MHz SMBus alert response or fast PMBus register reads.	Select ADUM1250ARZ only if system bus speed is capped at 1 MHz and magnetic immunity is prioritized over propagation delay.
ISO1540DR	2-channel, 1 Mbps max; 2500 VRMS; 3.3 V only; integrated 100 Ω series termination on outputs.	Fixed 3.3 V operation excludes 5 V legacy I²C peripherals; lacks −40 to +125 °C extended temp grade.	Choose ISO1540DR for cost-sensitive 3.3 V-only designs where extended temperature range and 1.7 MHz support are not required.

Compared with ADUM1250ARZ and ISO1540DR, SI8400AA-A-IS provides higher I²C bandwidth (1.7 MHz vs. 1 MHz), wider temperature range (−40 to +125 °C vs. −40 to +105 °C), and superior CMTI (25 kV/µs vs. 25 kV/µs for ADUM1250, 15 kV/µs for ISO1540), making it optimal for high-reliability industrial and PoE applications demanding full-speed SMBus/PMBus operation.

Availability

SI8400AA-A-IS is available at Aetrix Electronics and suitable for Power over Ethernet controllers, industrial motor control systems, intelligent power supply monitoring, and isolated SMPS with PMBus interfaces requiring stable component supply and long-term lifecycle support.

Supply support for SI8400AA-A-IS 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

Silicon Labs is a fabless semiconductor company specializing in precision timing, isolation, and wireless technologies for industrial, automotive, and IoT applications.

The Si840x product line was designed specifically to replace optocouplers in I²C/SMBus isolation applications - delivering lower power, smaller footprint, and guaranteed anti-latch operation without external components.

FAQ

What is the maximum I²C bus frequency supported by SI8400AA-A-IS?

The SI8400AA-A-IS supports a maximum I²C bus frequency of 1.7 MHz, as verified in Table 6 of the official datasheet under "Timing Specifications." This enables full-speed operation for SMBus Alert Response and PMBus READ_WORD_DATA commands without timing violations, provided external pull-up resistors are sized appropriately for bus capacitance.

Does SI8400AA-A-IS require external anti-latch circuitry for I²C isolation?

No, SI8400AA-A-IS does not require external anti-latch circuitry. Its internal design enforces VOL(Side A) > VIL(Side A) - with typical values of 910 mV (max VOL at 3 mA) and 450–780 mV (VIL range) - ensuring latch-free bidirectional SDA/SCL operation. This eliminates the need for discrete diodes or additional isolators in the signal path.

What safety certifications apply to SI8400AA-A-IS?

SI8400AA-A-IS is certified to UL 1577 (2500 VRMS), CSA Component Acceptance Notice 5A (IEC 60950-1/61010-1), and VDE 0884-2 (IEC 60747-5-2). These cover reinforced insulation up to 300 VRMS working voltage and validate its use in medical, industrial, and PoE equipment requiring regulatory approval.

Can SI8400AA-A-IS operate with mismatched supply voltages on Side A and Side B?

Yes, SI8400AA-A-IS supports independent 3.0–5.5 V supplies on AVDD and BVDD. This allows interfacing 3.3 V microcontrollers with 5 V I²C peripherals across the isolation barrier. Each side's logic thresholds scale with its local VDD, ensuring correct level translation without external level shifters.

Is SI8400AA-A-IS recommended for new designs?

No - Silicon Labs explicitly marks SI8400AA-A-IS as "Not Recommended for New Designs" in Rev. 1.6 of the datasheet (October 2013). While fully functional and supported, designers should evaluate newer alternatives like Si86xx or Si87xx families for improved power efficiency, higher CMTI, or enhanced package options before initiating new projects.

SI8400AA-A-IS Specifications

Product attributes: Attribute value

Manufacturer:: Skyworks Solutions Inc.

Series:: -

Package/Case:: 8-SOIC (0.154", 3.90mm Width)

Packaging:: Tube

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:: 1000Vrms

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

SI8400AA-A-IS FAQ

1.How can I place an order for SI8400AA-A-IS through Aetrix?

Please submit a Request for Quotation (RFQ) for SI8400AA-A-IS 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 SI8400AA-A-IS reliable?

The price and inventory of SI8400AA-A-IS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI8400AA-A-IS is usually 5 days.

3.What payment methods are accepted for SI8400AA-A-IS?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI8400AA-A-IS transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI8400AA-A-IS?

SI8400AA-A-IS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI8400AA-A-IS 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 SI8400AA-A-IS?

For technical support, including SI8400AA-A-IS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI8400AA-A-IS requirements.

6.How does Aetrix verify that SI8400AA-A-IS is sourced from the original manufacturer or authorized distributors?

All SI8400AA-A-IS 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 SI8400AA-A-IS meets industry standards.

7.What is the process for return or replacement of SI8400AA-A-IS?

All SI8400AA-A-IS units undergo pre-shipment inspection (PSI). If there is an issue with SI8400AA-A-IS, 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 SI8400AA-A-IS part is unused and in its original packaging.

Return procedure for SI8400AA-A-IS:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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