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Skyworks Solutions Inc. SI88421EC-ISR
- Part No.:
- SI88421EC-ISR
- Manufacturer:
- Skyworks Solutions Inc.
- Category:
- Digital Isolators
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SI88421EC-ISR.pdf
- Description:
- DGTL ISO 5000VRMS 2CH GP 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,502
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Product details
Overview
SI88421EC-ISR 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 output power, supporting data rates up to 100 Mbps, and providing 5000 VRMS reinforced isolation. It serves as a self-powered signal isolator in industrial motor control and EV inverter gate drive circuits.
For engineers reviewing the SI88421EC-ISR datasheet, SI88421EC-ISR pinout, SI88421EC-ISR application, or SI88421EC-ISR equivalent, this page delivers verified specifications, SOIC-20 wide-body package mapping, confirmed pin functions (including ESW, RSN, VREGA), automotive-grade AEC-Q100 qualification, and real-world design implications of its external-FET flyback architecture.
Technical Context
The SI88421EC-ISR implements two unidirectional RF-based digital isolation channels using capacitive silicon dioxide barriers, with on/off keying modulation enabling 18 ns typical propagation delay and 100 kV/µs transient immunity. Its DC-DC controller uses peak current mode control with secondary-side voltage sensing via VSNS and internal error encoding across the isolation barrier.
This variant belongs to the Si884xx family optimized for high-voltage primary-side operation (up to 24 V), requiring external NMOS switch (driven by ESW), current sense resistor (connected to RSN), and Type 1 loop compensation (RCOMP = 100 kΩ at COMP). It lacks SH/SH_FC and SS pins-shutdown and soft-start are not supported per datasheet Section 2.3.1–2.3.2.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Rating | 5000 VRMS for 1 minute (UL 1577, VDE 62368-1 reinforced) |
| Data Rate | Up to 100 Mbps - supports high-speed SPI, RS-485, and PWM feedback in motor drives |
| Propagation Delay | 18 ns typical - enables tight timing control in gate driver interfaces |
| DC-DC Output Power | 2 W average at 5.0 V - sufficient to power isolated gate drivers and MCU peripherals |
| Operating Temp | –40 °C to +125 °C - qualified for under-hood automotive and industrial ambient conditions |
| Transient Immunity | 100 kV/µs (typical) - withstands fast-switching noise in IGBT/SiC inverter environments |
| AEC-Q100 Grade | Qualified - meets automotive reliability requirements for EV traction inverters and BMS |
Pinout & Package
SI88421EC-ISR is housed in a RoHS-compliant SOIC-20 wide-body package (10.3 mm × 15.4 mm, 1.27 mm pitch) with creepage/clearance ≥8.3 mm, certified for reinforced insulation per VDE 62368-1.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6 | Primary-side digital I/O / control | A1, A2 (inputs); GNDP, RSN, ESW, VDDA - RSN senses primary current for external FET overcurrent protection; ESW drives external NMOS switch |
| 7, 8, 9, 10 | Digital channel outputs / ground | B1, B2 (outputs); GNDB, VDDB - isolated side powers local circuitry; VDDB must be ≤5.5 V |
| 11, 12, 13, 14, 15, 16 | DC-DC feedback & regulation | VSNS (secondary voltage sense), COMP (compensation node, RCOMP = 100 kΩ), VREGA (reference for external linear regulator if VDDA < 3.0 V), GNDA, NC |
| 17, 18, 19, 20 | Isolation barrier & unused | GNDP (primary ground), DNC/VREGB (Do Not Connect - internal Zener active only if VOUT > 5.5 V), NC, NC |
Key Features
| Feature | Design Value |
|---|---|
| RF-based digital isolation | Capacitive SiO₂ barrier enables 100 Mbps data rate and 18 ns prop delay without startup initialization |
| External-FET flyback DC-DC | ESW output drives external NMOS; RSN enables precise current limiting - supports 24 V input to 3.3/5.0 V isolated output |
| Secondary-side voltage sensing | VSNS feedback eliminates optocoupler dependency - improves load regulation and reduces BOM count |
| Automotive-ready design | AEC-Q100 qualified, IMDS/CAMDS listed, PPAP-supportable - suitable for ISO 26262 ASIL-B system integration |
| EMI-optimized control | Dithering and programmable switching frequency (200–800 kHz) minimize conducted/radiated emissions in noisy motor drive environments |
Applications
| Industrial Motor Control | EV Traction Inverter |
|---|---|
Use Scenario: Isolating PWM gate signals and current-sense feedback between MCU and IGBT/SiC half-bridge drivers in variable-frequency drives. IC Role / Device Role / Timing Role: Dual-channel isolator provides independent forward (A→B) and reverse (B→A) signal paths; integrated DC-DC powers isolated gate driver ICs. Use Value: Eliminates need for separate isolated DC supply; 18 ns prop delay ensures <100 ns total gate-loop latency for fast fault response. |
Use Scenario: Signal and power isolation in 400/800 V battery-connected inverters, where primary-side runs at 12–24 V and secondary-side requires clean 5 V for gate drivers and sensors. IC Role / Device Role / Timing Role: SI88421EC-ISR supplies isolated 5 V while transmitting phase-current feedback and desaturation signals across 5 kVRMS barrier. Use Value: External-FET architecture handles 24 V input directly - avoids pre-regulation losses and improves system efficiency by >3% vs. two-stage isolation. |
| Programmable Logic Controller (PLC) | Isolated Data Acquisition |
Use Scenario: Digital I/O module isolating field-side 24 V digital inputs/outputs from backplane 3.3 V logic in harsh factory environments. IC Role / Device Role / Timing Role: SI88421EC-ISR provides galvanic separation for discrete I/O lines while powering isolated level translators and bus transceivers. Use Value: 100 kV/µs CMTI rating prevents false triggering during lightning-induced surges on industrial wiring. |
Use Scenario: Isolating analog front-end ADCs and microcontrollers in high-precision current/voltage monitoring systems for solar string inverters. IC Role / Device Role / Timing Role: SI88421EC-ISR transmits serial interface (SPI) clock/data across isolation barrier and powers isolated ADC reference buffers. Use Value: Secondary-side VSNS sensing ensures stable 5 V supply despite ±10% input ripple - maintains ADC reference accuracy within 0.1%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-channel isolated DC-DC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADUM6421ARWZ | Integrated power switches (no ESW/RSN); 500 mW max output; SOIC-20; no AEC-Q100 | Limited to low-power isolated logic; unsuitable for 24 V input or >1 W loads | Choose ADUM6421ARWZ only for space-constrained, low-power 3.3/5 V-to-3.3/5 V designs without automotive qualification needs. |
| SI88621EC-ISR | Same Si884xx/6xx family; adds SH_FC and SS pins for shutdown/frequency control; identical ESW/RSN/VSNS architecture | Enables programmable frequency (200–800 kHz) and external-triggered shutdown - useful for EMI-sensitive or safety-critical systems | Select SI88621EC-ISR when soft-start, frequency tuning, or controlled shutdown are required; otherwise SI88421EC-ISR offers simpler layout and lower cost. |
Compared with ADUM6421ARWZ, SI88421EC-ISR delivers 4× higher isolated power and automotive qualification but requires external FET design; versus SI88621EC-ISR, it trades away programmable features for reduced component count and deterministic startup behavior.
Availability
SI88421EC-ISR is available at Aetrix Electronics and suitable for industrial motor control, EV traction inverters, and PLC I/O modules requiring stable component supply, long-term lifecycle support, and automotive-grade traceability.
Supply support for SI88421EC-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 semiconductor company specializing in analog and mixed-signal connectivity solutions, with leadership in RF, timing, and isolation technologies for communications, automotive, and industrial markets.
The Si88xx family was engineered specifically for high-reliability isolated power and signal transfer in electric vehicle powertrains and industrial automation, combining RF isolation with flexible flyback DC-DC topologies to replace optocouplers and discrete isolated supplies.
FAQ
What is the maximum input voltage supported by SI88421EC-ISR's DC-DC converter?
The SI88421EC-ISR is designed for high-voltage primary-side operation, supporting up to 24 V DC input. Its external-FET architecture (via ESW and RSN pins) enables safe switching at this voltage level without internal power switch limitations. Input voltages above 5.5 V require use of the VREGA pin with an external NPN transistor to regulate VDDA, as specified in the datasheet Section 2.3.5. This makes SI88421EC-ISR suitable for direct connection to 12 V or 24 V industrial and automotive rails.
Does SI88421EC-ISR support shutdown or soft-start functionality?
No, SI88421EC-ISR does not include shutdown (SH/SH_FC) or soft-start (SS) functionality. Per datasheet Section 2.3.1–2.3.2, these features are explicitly unavailable on the Si884xx series. The device starts up automatically when VDDA exceeds UVLO thresholds, with no user-controllable sequencing. For designs requiring controlled enable/disable or inrush limiting, SI88621EC-ISR - which includes SH_FC and SS pins - is the functionally aligned alternative within the same family.
What transformer is recommended for SI88421EC-ISR in a 24 V to 5 V isolated supply?
Skyworks validates the UMEC UTB02250s and Coilcraft TA7788-AL transformers for 24 V input to 5 V output with SI88421EC-ISR. Both meet 5 kVRMS isolation, 600–554 nH leakage inductance, and 25 µH primary inductance requirements. The UTB02250s supports 7–24 V input range and is AEC-Q200 qualified, making it preferred for automotive applications; the TA7788-AL offers tighter leakage tolerance and is ideal for high-EMI industrial settings. Transformer selection must match the 3.0:1.0 turns ratio specified for high-voltage-to-low-voltage configurations.
Can SI88421EC-ISR power external circuitry beyond its own VDDB supply?
Yes, SI88421EC-ISR can deliver up to 2 W average isolated output power - sufficient to power not only its own VDDB (≤5.5 V) but also external loads such as gate driver ICs, isolated ADCs, or CAN transceivers. The output voltage is set by the R1/R2 resistor divider on the VSNS pin, and regulation is maintained via secondary-side sensing. When supplying external loads, ensure total current draw remains within thermal limits and that output capacitor (C3) and compensation network (RCOMP/CCOMP) are sized per AN901 guidelines to preserve stability under dynamic load steps.
Is SI88421EC-ISR pin-compatible with other Si884xx variants like SI88420 or SI88422?
No, SI88421EC-ISR is not pin-compatible with SI88420 or SI88422. As shown in Figure 3 of the datasheet, SI88421 has a unique pinout: A1/A2 on pins 7/8 and B1/B2 on pins 9/10, with ESW on pin 3 and RSN on pin 2. SI88420 places A1/A2 on pins 1/2 and B1/B2 on pins 3/4; SI88422 duplicates A1/A2 and B1/B2 across four pins (1/2/3/4 and 17/18/19/20). PCB layout must be specific to SI88421EC-ISR - no shared footprint exists across the Si8842x variants.
SI88421EC-ISR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Skyworks Solutions Inc.
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- 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:
- -
- Qualification:
- -
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SI88421EC-ISR FAQ
1.How can I place an order for SI88421EC-ISR through Aetrix?
Please submit a Request for Quotation (RFQ) for SI88421EC-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 SI88421EC-ISR reliable?
The price and inventory of SI88421EC-ISR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI88421EC-ISR is usually 5 days.
3.What payment methods are accepted for SI88421EC-ISR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI88421EC-ISR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SI88421EC-ISR?
SI88421EC-ISR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SI88421EC-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 SI88421EC-ISR?
For technical support, including SI88421EC-ISR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI88421EC-ISR requirements.
6.How does Aetrix verify that SI88421EC-ISR is sourced from the original manufacturer or authorized distributors?
All SI88421EC-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 SI88421EC-ISR meets industry standards.
7.What is the process for return or replacement of SI88421EC-ISR?
All SI88421EC-ISR units undergo pre-shipment inspection (PSI). If there is an issue with SI88421EC-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 SI88421EC-ISR part is unused and in its original packaging.
Return procedure for SI88421EC-ISR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SI88421EC-ISR Tags
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ISO1212DBQR
Texas Instruments
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ISO6721BDR
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SI8710AC-B-ISR
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ISO7720FDR
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ISO7721DR
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ISO7721FDR
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SI8710CC-B-ISR
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ISO6741FQDWRQ1
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ISO7721DWVR
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ISO7762FDBQR
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ISO7741DWR
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ISO7741FDWR
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