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Skyworks Solutions Inc. SI88421BC-ASR
- Part No.:
- SI88421BC-ASR
- Manufacturer:
- Skyworks Solutions Inc.
- Category:
- Digital Isolators
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SI88421BC-ASR.pdf
- Description:
- LINEAR IC
- Quantity:
- Payment:
- Shipping:
Inventory:4,842
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Product details
Overview
SI88421BC-ASR from Skyworks Solutions is a dual-channel digital isolator with integrated isolated DC-DC converter, designed for high-voltage-to-low-voltage conversion (e.g., 24 V input to 3.3/5.0 V isolated output), delivering up to 2 W average isolated power, supporting data rates up to 100 Mbps, and providing 5000 VRMS isolation. It serves as a complete signal + power isolation solution in industrial motor drives and EV battery management systems.
For engineers reviewing the SI88421BC-ASR datasheet, SI88421BC-ASR pinout, SI88421BC-ASR application, or SI88421BC-ASR equivalent, this page delivers verified technical context, SOIC-20 wide-body package mapping, confirmed pin functions (including ESW, RSN, VREGA), real-world timing performance (18 ns typical propagation delay), and validated alternative options for high-voltage isolated power + signal transfer.
Technical Context
The SI88421BC-ASR implements two unidirectional RF-based digital isolation channels using capacitive silicon dioxide barriers, with on/off keying modulation for superior noise immunity and magnetic field rejection. Its isolated DC-DC converter uses modified flyback topology with external NMOS switch control via ESW pin and primary-side current sensing via RSN pin.
This variant is specifically configured for high-voltage input (up to 24 V) to low-voltage isolated output (3.3/5.0 V), requiring external power FET and transformer. It lacks SH/SH_FC and SS pins-shutdown and soft-start are not supported-and uses fixed 250 kHz switching frequency with internal compensation resistor of 100 kΩ at COMP pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Rating | 5000 VRMS for 1 minute - meets reinforced insulation requirements per UL 1577, CSA 62368-1, VDE 62368-1 |
| Data Rate | Up to 100 Mbps - supports high-speed serial interfaces including SPI, RS-485, and digital I/O in real-time control loops |
| Propagation Delay | 18 ns typical, 23 ns max - enables precise timing-critical applications such as gate driver feedback and encoder signal isolation |
| DC-DC Output Power | 2 W average at 5.0 V - sufficient to power secondary-side microcontrollers, ADCs, and isolated transceivers without external regulators |
| Input Voltage Range | Up to 24 V on primary side - supports direct connection to industrial 24 V rails or automotive battery domains |
| Operating Temp | –40 °C to +125 °C - qualified per AEC-Q100 Grade 1 for under-hood and industrial ambient conditions |
| Transient Immunity | 100 kV/µs typical - ensures robust operation in noisy motor drive and inverter environments with fast dv/dt edges |
Pinout & Package
SI88421BC-ASR is housed in a RoHS-compliant SOIC-20 wide-body package (10.3 mm × 7.5 mm, 1.0 mm height) with creepage/clearance ≥ 8.3 mm, certified for reinforced insulation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 | NC or DNC/VREGB | Pins 1–5, 11–15, 17–20 are no-connect; Pin 6 is DNC/VREGB - internally zener-referenced, used only when output voltage > 5.5 V |
| A1, A2 | Primary-side digital input | Unidirectional CMOS inputs accepting 3.3/5.0 V logic; tied to VDDA (≤5.5 V) and GNDA |
| B1, B2 | Secondary-side digital output | Unidirectional CMOS outputs referenced to VDDB; support 3.3/5.0 V levels with rail-to-rail swing |
| VDDA | Primary-side signal supply | Must be ≤5.5 V; powers digital transmitter circuitry; requires local 0.1 µF bypass to GNDA |
| VDDB | Secondary-side signal supply | Powered by isolated DC-DC output; supplies receiver logic and output drivers |
| GNDP | Primary-side power ground | Reference for VDDP and ESW; must be short-traced to VDDP and connected directly to ground plane |
| GNDA | Primary-side signal ground | Separate from GNDP; connects to VDDA return; must be short-traced to VDDA |
| GNDB | Secondary-side signal ground | Reference for VDDB and B1/B2; connects to VSNS and COMP return |
| ESW | External switch driver | Drives gate of external NMOS FET (Q1); operates at 250 kHz; requires RC snubber to suppress VSW ringing |
| RSN | Current sense input | Monitors primary-side switch current via shunt resistor; enables cycle-skipping and overcurrent protection |
| VREGA | Voltage reference output | Zener-referenced 5.0 V output; used with external NPN transistor to generate VDDA if primary supply > 5.5 V |
| VSNS | Feedback voltage input | Accepts resistor-divider output from isolated secondary; sets regulated VDDB via internal error amplifier |
| COMP | Compensation node | Connect 100 kΩ resistor + capacitor to GNDB for Type-1 loop compensation; critical for stable 24 V → 5 V regulation |
Key Features
| Feature | Design Value |
|---|---|
| RF-based digital isolation | Capacitive SiO₂ barrier with on/off keying - eliminates magnetic coupling issues and enables >100 kV/µs CMTI without shielding |
| High-voltage DC-DC architecture | External-FET flyback with primary-side current sensing (RSN) and secondary-side voltage feedback (VSNS) - supports 24 V input while maintaining tight load regulation |
| Integrated VREGA reference | On-chip 5.0 V Zener output - eliminates need for separate LDO to bias VDDA when primary rail exceeds 5.5 V |
| AEC-Q100 qualification | Grade 1 temperature range (–40 °C to +125 °C) with AIAG PPAP and IMDS support - suitable for automotive battery disconnect units and BMS |
| Thermal shutdown protection | Automatic junction temperature cutoff - prevents permanent damage during overload or poor heatsinking in enclosed industrial enclosures |
Applications
| Motor Drive Isolation | Battery Management Systems |
|---|---|
Use Scenario: Isolating gate driver signals and current-sense feedback in 3-phase IGBT/SiC inverter stages powered from 24 V or 48 V DC bus. IC Role / Device Role / Timing Role: SI88421BC-ASR provides dual-channel signal isolation plus 5 V isolated supply for gate driver ICs and ADC front-ends. Use Value: Eliminates optocouplers and isolated DC-DC modules, reducing BOM count by 3+ components while maintaining 23 ns max propagation delay for precise PWM timing. | Use Scenario: Monitoring cell voltages and pack currents in EV traction battery packs where primary side connects to 24–48 V auxiliary supply and secondary side interfaces with MCU over isolated SPI. IC Role / Device Role / Timing Role: SI88421BC-ASR isolates analog front-end digital control lines and powers isolated ADC reference and level-shifters. Use Value: Enables single-component isolation + power for 16-cell BMS stacks, meeting AEC-Q100 and UL 5000 VRMS safety requirements without external regulators. |
| Industrial PLC I/O Modules | Renewable Energy Inverters |
Use Scenario: Digitally isolating 24 V digital input/output channels in modular PLC backplanes with centralized 24 V supply. IC Role / Device Role / Timing Role: SI88421BC-ASR isolates status and command signals while powering isolated level translators and LED indicators on field-side PCB sections. Use Value: Supports hot-swap I/O modules with 5000 VRMS working voltage and 8.3 mm creepage, eliminating need for separate isolated DC-DC for each slot. | Use Scenario: Isolating communication between central controller and string-level optimizers or microinverters in solar PV systems with 24–60 V DC input rails. IC Role / Device Role / Timing Role: SI88421BC-ASR isolates UART/RS-485 control signals and supplies isolated 3.3 V for local MCU and sensor interface. Use Value: Delivers certified reinforced insulation and 100 kV/µs CMTI in outdoor-rated enclosures, enabling compliance with IEC 62109 and UL 1741 without additional filtering. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-channel isolated power + signal applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADUM6421AARWZ | 4-channel isolator with integrated 500 mW isolated DC-DC; SOIC-20; 5000 VRMS; 25 Mbps max data rate | Lower power (0.5 W vs. 2 W), lower speed (25 Mbps vs. 100 Mbps), no external FET support | Choose ADUM6421AARWZ for space-constrained, lower-power applications where full 2 W is unnecessary and 25 Mbps suffices. |
| ISO7842FDWR | 2-channel isolator only - no integrated DC-DC; requires external isolated power supply; SOIC-16; 5000 VRMS; 100 Mbps | No power integration - increases BOM, layout area, and design complexity for isolated supply generation | Choose ISO7842FDWR only when existing isolated power architecture exists and maximum channel density per mm² is prioritized over system-level integration. |
Compared with ADUM6421AARWZ and ISO7842FDWR, SI88421BC-ASR uniquely combines 2 W isolated power delivery, 100 Mbps speed, and external-FET scalability for 24 V input systems - making it optimal for new designs requiring both high-speed signal integrity and self-contained isolated power without compromising safety certification.
Availability
SI88421BC-ASR is available at Aetrix Electronics and suitable for industrial motor control, automotive battery management, and renewable energy inverters requiring stable component supply, long-term lifecycle assurance, and AEC-Q100-compliant sourcing.
Supply support for SI88421BC-ASR 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 high-reliability applications.
The Si88xx family was engineered to replace optocoupler + discrete DC-DC combinations in industrial and automotive systems, delivering integrated signal + power isolation with reinforced safety certification and extended temperature operation.
FAQ
What is the maximum input voltage supported by SI88421BC-ASR?
The SI88421BC-ASR supports primary-side input voltages up to 24 V DC. Its high-voltage configuration uses external NMOS switching (driven by ESW pin) and primary-side current sensing (via RSN pin), enabling safe operation across industrial 24 V rails and automotive auxiliary domains without internal switch limitations.
Does SI88421BC-ASR include shutdown or soft-start functionality?
No, SI88421BC-ASR does not include shutdown (SH) or soft-start (SS) functionality. As confirmed in Section 2.3.1 and 2.3.2 of the datasheet, these features are unavailable on Si884xx variants. The device starts automatically when VDDA and VDDP rise above UVLO thresholds, with no user-controllable enable or ramp control.
What transformer is recommended for SI88421BC-ASR in a 24 V to 5 V application?
Skyworks validates the UMEC UTB02250s and Coilcraft TA7788-AL transformers for 24 V input to 5 V output use with SI88421BC-ASR. Both meet 5 kVRMS isolation, ≤600 nH leakage inductance, and 25 µH ±5% primary inductance - ensuring stable regulation and EMI compliance per AN901 design guidelines.
Can SI88421BC-ASR power external circuitry beyond its own VDDB supply?
Yes, SI88421BC-ASR can deliver up to 2 W average isolated power - sufficient to power its own VDDB domain plus external loads such as isolated ADCs, transceivers, or microcontroller peripherals. Output voltage is set via VSNS resistor divider, and regulation remains stable under full load with proper transformer and compensation design.
Is SI88421BC-ASR qualified for automotive applications?
Yes, SI88421BC-ASR is AEC-Q100 qualified (Grade 1, –40 °C to +125 °C) and supports AIAG-compliant PPAP documentation and IMDS/CAMDS listings. It is certified to UL 1577, CSA 62368-1, and VDE 62368-1 for reinforced insulation - making it suitable for automotive battery disconnect units, onboard chargers, and 12/24 V domain controllers.
SI88421BC-ASR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Skyworks Solutions Inc.
- Series:
- Si88x2x
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Technology:
- Capacitive Coupling
- Type:
- General Purpose
- Isolated Power:
- Yes
- Number of Channels:
- 2
- Inputs - Side 1/Side 2:
- 1/1
- Channel Type:
- Unidirectional
- Voltage - Isolation:
- 5000Vrms
- Common Mode Transient Immunity (Min):
- 40kV/µs
- Data Rate:
- 100Mbps
- Propagation Delay tpLH / tpHL (Max):
- 18ns, 23ns
- Pulse Width Distortion (Max):
- 7ns
- Rise / Fall Time (Typ):
- 2.5ns, 2.5ns
- Voltage - Supply:
- 3V ~ 5.5V
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SI88421BC-ASR FAQ
1.How can I place an order for SI88421BC-ASR through Aetrix?
Please submit a Request for Quotation (RFQ) for SI88421BC-ASR 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 SI88421BC-ASR reliable?
The price and inventory of SI88421BC-ASR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI88421BC-ASR is usually 5 days.
3.What payment methods are accepted for SI88421BC-ASR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI88421BC-ASR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SI88421BC-ASR?
SI88421BC-ASR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SI88421BC-ASR 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 SI88421BC-ASR?
For technical support, including SI88421BC-ASR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI88421BC-ASR requirements.
6.How does Aetrix verify that SI88421BC-ASR is sourced from the original manufacturer or authorized distributors?
All SI88421BC-ASR 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 SI88421BC-ASR meets industry standards.
7.What is the process for return or replacement of SI88421BC-ASR?
All SI88421BC-ASR units undergo pre-shipment inspection (PSI). If there is an issue with SI88421BC-ASR, 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 SI88421BC-ASR part is unused and in its original packaging.
Return procedure for SI88421BC-ASR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SI88421BC-ASR Tags
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ISO6721BDR
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SI8710AC-B-ISR
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SI8710CC-B-ISR
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ISO7741FDWR
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