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Skyworks Solutions Inc. SI8421-C-IS
- Part No.:
- SI8421-C-IS
- Manufacturer:
- Skyworks Solutions Inc.
- Category:
- Digital Isolators
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SI8421-C-IS.pdf
- Description:
- DGTL ISO 2500VRMS 2CH GP 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,915
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Product details
Overview
SI8421-C-IS from Silicon Laboratories is a dual-channel digital isolator with 150 Mbps data rate, <7.5 ns propagation delay, and 2500 VRMS isolation rating in an 8-pin narrow-body SOIC package. It operates across 2.375–5.5 V supply range on both sides and supports isolated motor control, ADC/DAC interfaces, and power factor correction systems.
For engineers reviewing the SI8421-C-IS datasheet, SI8421-C-IS pinout, SI8421-C-IS application, or SI8421-C-IS equivalent, key selection criteria include channel configuration (1 input / 1 output), high-speed timing performance at 150 Mbps, common-mode transient immunity >25 kV/µs, and compliance with UL1577, CSA, and IEC 60747-5-2 safety standards.
Technical Context
The SI8421-C-IS implements RF-based isolation using on-off keying of a ~2.1 GHz carrier across integrated transformers, eliminating startup initialization and enabling DC-correct signal transmission. Its architecture provides precise timing with ≤3.5 ns pulse width distortion and ≤3 ns channel-to-channel skew at 150 Mbps.
It features independent dual-supply operation (VDD1/VDD2), bidirectional channel capability (A1/B1 and A2/B2), and robust immunity to fast transients (>25 kV/µs CMTI) without requiring external components for basic functionality.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Max Data Rate | 150 Mbps - supports high-speed serial interfaces like SPI, RS-485, and isolated CAN FD physical layer signaling |
| Propagation Delay | 4–10 ns - enables tight timing budgets in real-time motor control and feedback loops |
| Pulse Width Distortion | ≤3.5 ns - preserves duty cycle integrity for PWM signals and clock distribution |
| Channel-Channel Skew | ≤3 ns - ensures synchronized sampling across dual ADC channels or complementary gate drive signals |
| Isolation Rating | 2500 VRMS - meets reinforced insulation requirements for industrial mains-connected equipment per UL1577 |
| CMTI | >25 kV/µs - maintains data integrity during fast switching events in IGBT/MOSFET gate drivers |
| Supply Voltage Range | 2.375–5.5 V per side - interoperates with 3.3 V microcontrollers and 5 V analog front-ends without level shifters |
Pinout & Package
SI8421-C-IS uses an 8-pin narrow-body SOIC package (JEDEC MS-012, 3.9 mm body width). Pin assignments are validated per Silicon Labs Preliminary Rev. 0.12 documentation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD1 | Side 1 Power Supply | Supplies logic side (A1/A2 inputs/outputs); must be bypassed with 0.1 µF capacitor near pin |
| A1 | Digital I/O (Side 1) | First bidirectional channel terminal; compatible with CMOS logic levels |
| GND1 | Side 1 Ground | Reference for VDD1 domain; requires separate ground plane from GND2 |
| VDD2 | Side 2 Power Supply | Supplies isolated side (B1/B2); independent voltage rail enables level shifting |
| B1 | Digital I/O (Side 2) | Second bidirectional channel terminal; electrically isolated from A1/A2 |
| GND2 | Side 2 Ground | Reference for VDD2 domain; galvanically separated from GND1 by transformer barrier |
| A2 | Digital I/O (Side 1) | Second bidirectional channel terminal on primary side |
| B2 | Digital I/O (Side 2) | Second bidirectional channel terminal on isolated side |
Key Features
| Feature | Design Value |
|---|---|
| RF-based isolation | Eliminates LED aging and temperature drift issues found in optocouplers; enables stable 150 Mbps operation over –40°C to +125°C |
| No start-up initialization | Delivers valid output within <10 µs of power application - critical for fail-safe motor shutdown sequences |
| DC-correct transmission | Maintains exact duty cycle and logic state during extended low-frequency or static conditions - essential for PWM gate drives |
| Independent dual supplies | Allows VDD1 = 3.3 V (MCU side) and VDD2 = 5 V (analog/power side) without external level translation |
| High CMTI immunity | Withstands >25 kV/µs common-mode transients - prevents false triggering in noisy inverter environments |
Applications
| Motor Control Systems | Isolated Data Acquisition |
|---|---|
Use Scenario: Isolating gate drive signals and current sense feedback in 3-phase inverters for HVAC compressors and EV traction drives. IC Role / Device Role / Timing Role: SI8421-C-IS provides bidirectional isolation between MCU PWM outputs and IGBT gate drivers while synchronizing current-sense ADC readouts. Use Value: ≤3 ns channel skew ensures precise phase alignment of gate signals; 150 Mbps supports high-resolution encoder interpolation data transfer. | Use Scenario: Isolating SPI communication between a host processor and isolated 16-bit sigma-delta ADC in industrial process monitoring. IC Role / Device Role / Timing Role: SI8421-C-IS carries clock and data across isolation barrier with <7.5 ns propagation delay to maintain sampling coherence. Use Value: ≤3.5 ns pulse width distortion preserves SPI clock duty cycle, preventing setup/hold violations at 20 MHz SCLK. |
| Power Factor Correction (PFC) | Industrial PLC I/O Modules |
Use Scenario: Isolating voltage and current sensing inputs and PWM control outputs in active PFC boost converters for server PSUs. IC Role / Device Role / Timing Role: SI8421-C-IS transmits zero-crossing detection signals and control commands across reinforced insulation barrier. Use Value: 2500 VRMS isolation and >25 kV/µs CMTI prevent noise coupling during MOSFET switching transitions at 100+ kHz. | Use Scenario: Providing isolated digital input conditioning and output driving in modular PLC backplanes handling 24 VDC field signals. IC Role / Device Role / Timing Role: SI8421-C-IS interfaces microcontroller GPIOs to opto-coupled input stages and relay driver ICs on isolated side. Use Value: Dual-channel architecture reduces component count vs. two single-channel isolators; SOIC-8 footprint simplifies PCB layout in space-constrained modules. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar digital isolator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADUM1201BRZ | 100 Mbps max data rate; 15 ns propagation delay; 2500 VRMS isolation; uses iCoupler® capacitive technology | Limited to lower-speed industrial bus interfaces (e.g., I²C, slower SPI); less suitable for 150 Mbps encoder links | Select when cost sensitivity outweighs speed requirement and existing ADI ecosystem integration is prioritized |
| ISO6721DR | 50 Mbps max data rate; 25 ns propagation delay; 5000 VRMS isolation; uses capacitive isolation with integrated LDO | Better suited for high-isolation medical/safety-critical systems but lacks bandwidth for real-time motor control loops | Prefer when reinforced 5 kVRMS isolation is mandatory and system data rates remain below 50 Mbps |
Compared with ADUM1201BRZ and ISO6721DR, SI8421-C-IS delivers the highest data throughput (150 Mbps) and lowest timing uncertainty (≤3 ns skew), making it uniquely suitable for closed-loop motor control and high-resolution isolated data acquisition where nanosecond-level synchronization is required.
Availability
SI8421-C-IS is available at Aetrix Electronics and suitable for motor control systems, isolated data acquisition, power factor correction circuits, and industrial PLC I/O modules requiring stable component supply and long-term lifecycle support.
Supply support for SI8421-C-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 Laboratories Inc. is a fabless semiconductor company specializing in mixed-signal ICs for timing, isolation, wireless, and energy-efficient MCU applications.
The Si84xx family was designed specifically to replace optocouplers in high-reliability industrial and automotive systems, delivering superior speed, timing precision, and lifetime stability through RF-based transformer isolation.
FAQ
What is the maximum operating temperature for SI8421-C-IS at 150 Mbps?
The SI8421-C-IS supports continuous operation up to +100°C ambient temperature when running at its full 150 Mbps data rate, as specified in Table 5 of the preliminary datasheet. At lower speeds (e.g., 100 Mbps), operation extends to +125°C. This thermal derating ensures reliable performance in enclosed motor drive enclosures and high-density power supplies where airflow is limited.
Does SI8421-C-IS require external components for basic isolation functionality?
No, SI8421-C-IS requires only two 0.1 µF bypass capacitors-one between VDD1 and GND1, and another between VDD2 and GND2-placed adjacent to the package. Unlike optocouplers, it needs no pull-up resistors, level shifters, or startup calibration circuitry. Its RF-based architecture enables immediate operation after power application with <10 µs startup time.
How does SI8421-C-IS achieve DC-correct signal transmission?
SI8421-C-IS uses RF carrier modulation with on-off keying and built-in encoding/decoding logic that continuously monitors input state, ensuring accurate reproduction of static logic levels and low-frequency signals. This eliminates baseline drift and duty-cycle degradation inherent in optocouplers, making SI8421-C-IS suitable for PWM gate drive and precision analog feedback isolation.
Can SI8421-C-IS be used in bidirectional communication configurations?
Yes, each channel (A1/B1 and A2/B2) of SI8421-C-IS is fully bidirectional and supports data flow in either direction without hardware reconfiguration. This enables flexible use in half-duplex protocols like isolated I²C or custom command-response interfaces where the same pin pair handles both transmit and receive functions across the isolation barrier.
What safety certifications apply to SI8421-C-IS?
SI8421-C-IS is certified to UL1577 (2500 VRMS, 1 minute), CSA Component Acceptance Notice, and IEC 60747-5-2 (VDE 0884-2), with validated creepage (4.60 mm) and clearance (5.0 mm) distances. These approvals confirm suitability for reinforced insulation in industrial equipment operating from 100–240 VAC mains, including motor drives and programmable logic controllers.
SI8421-C-IS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Skyworks Solutions Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Technology:
- Capacitive Coupling
- Type:
- General Purpose
- Isolated Power:
- No
- Number of Channels:
- 2
- Inputs - Side 1/Side 2:
- 1/1
- Channel Type:
- Unidirectional
- Voltage - Isolation:
- 2500Vrms
- Common Mode Transient Immunity (Min):
- 25kV/µs
- Data Rate:
- 150Mbps
- Propagation Delay tpLH / tpHL (Max):
- 9.5ns, 9.5ns
- Pulse Width Distortion (Max):
- 3.5ns
- Rise / Fall Time (Typ):
- 2ns, 2ns
- Voltage - Supply:
- 2.375V ~ 5.5V
- Grade:
- -
- Qualification:
- -
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
SI8421-C-IS FAQ
1.How can I place an order for SI8421-C-IS through Aetrix?
Please submit a Request for Quotation (RFQ) for SI8421-C-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 SI8421-C-IS reliable?
The price and inventory of SI8421-C-IS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI8421-C-IS is usually 5 days.
3.What payment methods are accepted for SI8421-C-IS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI8421-C-IS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SI8421-C-IS?
SI8421-C-IS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SI8421-C-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 SI8421-C-IS?
For technical support, including SI8421-C-IS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI8421-C-IS requirements.
6.How does Aetrix verify that SI8421-C-IS is sourced from the original manufacturer or authorized distributors?
All SI8421-C-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 SI8421-C-IS meets industry standards.
7.What is the process for return or replacement of SI8421-C-IS?
All SI8421-C-IS units undergo pre-shipment inspection (PSI). If there is an issue with SI8421-C-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 SI8421-C-IS part is unused and in its original packaging.
Return procedure for SI8421-C-IS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SI8421-C-IS 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
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ISO7721DWVR
Texas Instruments
-
ISO7762FDBQR
Texas Instruments
-
ISO7741DWR
Texas Instruments
-
ISO7741FDWR
Texas Instruments
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