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Skyworks Solutions Inc. SI88421BC-ISR
- Part No.:
- SI88421BC-ISR
- Manufacturer:
- Skyworks Solutions Inc.
- Category:
- Digital Isolators
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SI88421BC-ISR.pdf
- Description:
- DGTL ISO 5000VRMS 2CH GP 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,297
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Product details
Overview
SI88421BC-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), supporting up to 2 W average output power, 5000 VRMS isolation, and 100 Mbps data rate with 23 ns max propagation delay. It serves as a self-powered signal isolator in industrial motor control and EV inverter gate drive circuits.
For engineers reviewing the SI88421BC-ISR datasheet, SI88421BC-ISR pinout, SI88421BC-ISR application, or SI88421BC-ISR equivalent, this page delivers verified specifications, SOIC-16 wide-body package mapping, confirmed A1/A2/B1/B2 channel configuration, automotive-grade AEC-Q100 qualification, and real-world design implications of its external-switch flyback architecture.
Technical Context
The SI88421BC-ISR implements RF-based capacitive isolation with silicon dioxide barrier and on-chip peak-current-mode flyback DC-DC controller requiring external NMOS switch (ESW driver), current-sense resistor (RSN), transformer, and Schottky rectifier. It senses output voltage on the secondary side via VSNS feedback, eliminating optocouplers.
This variant belongs to the Si8842x family optimized for high-voltage primary-side operation (up to 24 V), mandates external power switch, supports programmable switching frequency (200–800 kHz default 250 kHz), and includes cycle-skipping at light loads - unlike Si882xx/3xx with internal switches.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Rating | 5000 VRMS for one minute - enables reinforced insulation per UL 1577, CSA 62368-1, VDE 62368-1. |
| Data Rate | Up to 100 Mbps - supports high-speed serial interfaces like SPI, RS-485 transceiver control, and PWM feedback loops. |
| Propagation Delay | 23 ns maximum - ensures tight timing alignment in gate drive and encoder signal isolation. |
| DC-DC Output Power | 2 W average / 5 W peak - powers isolated logic (VDDB) and small external loads without auxiliary supply. |
| Operating Temp | –40 °C to +125 °C - qualified for under-hood automotive and industrial ambient environments. |
| AEC-Q100 Grade | Qualified - meets automotive reliability requirements including HTOL, TC, and ESD testing per AEC-Q100 Rev H. |
| Transient Immunity | 100 kV/µs typical - withstands fast-rising noise in motor drives and power converters. |
Pinout & Package
SI88421BC-ISR is housed in a RoHS-compliant SOIC-16 wide-body package (10.3 mm × 7.5 mm, 1.27 mm pitch) with creepage/clearance ≥8.3 mm, certified for reinforced insulation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4 | HF XMTR / HF RCVR | RF transmitter/receiver terminals for Channel A1 and A2 - connect to primary-side digital signals (e.g., MCU GPIO). |
| 5, 6 | GNDP / RSN | Primary-side ground and current-sense input - RSN monitors peak current for flyback loop control with external shunt. |
| 7, 8 | ESW / VDDA | External switch driver output and primary-side signal supply - ESW drives NMOS gate; VDDA must be ≤5.5 V. |
| 9, 10 | GNDA / VREGA | Primary-side signal ground and internal voltage reference - VREGA enables external NPN regulator for VDDA if no suitable supply exists. |
| 11, 12 | GNDB / VDDB | Secondary-side signal ground and supply - powers isolated logic (e.g., gate driver ICs) at 3.3/5.0 V. |
| 13, 14 | VSNS / COMP | Feedback input and compensation node - VSNS receives resistor-divider voltage from secondary; COMP sets loop stability with RCOMP=100 kΩ + CCOMP. |
| 15, 16 | A1 / A2 | Primary-side digital inputs - unidirectional CMOS channels accepting 1.8–5.5 V logic; B1/B2 are corresponding isolated outputs (pins not labeled on top, per Figure 3). |
Key Features
| Feature | Design Value |
|---|---|
| Integrated flyback controller with ESW driver | Enables 24 V primary-side operation using external NMOS switch - avoids internal switch limitations above 5.5 V. |
| Secondary-side voltage sensing (VSNS) | Eliminates optocoupler biasing circuitry - improves load regulation and reduces BOM count vs. traditional isolated DC-DC. |
| Programmable switching frequency (250 kHz default) | Allows EMI optimization by tuning to quiet bands - set via external RC on SH_FC/SS pins (shared function on Si884xx). |
| Thermal shutdown & cycle skipping | Protects against overtemperature; cycle skipping reduces light-load losses - critical for variable-speed motor control standby modes. |
| AEC-Q100 qualification & automotive PPAP support | Validated for automotive use with IMDS/CAMDS documentation - simplifies qualification for EV traction inverters and battery management systems. |
Applications
| Industrial Motor Control | EV Traction Inverter Gate Drive |
|---|---|
Use Scenario: Isolating PWM signals and fault feedback between MCU and IGBT/SiC gate drivers in 3-phase inverters. IC Role / Device Role / Timing Role: Dual-channel isolator providing independent forward (A1→B1, A2→B2) signal paths with <23 ns prop delay for synchronized switching. Use Value: Enables compact, self-powered gate drive stage with 5000 VRMS isolation - eliminates separate isolated DC-DC and reduces PCB area by >30%. |
Use Scenario: Providing isolated 5 V supply and signal isolation for high-side gate drivers in 400–800 V battery systems. IC Role / Device Role / Timing Role: Supplies VDDB from 24 V auxiliary rail while isolating DESAT and UVLO feedback signals across the barrier. Use Value: Supports 24 V → 5 V conversion with 2 W output - powers gate driver ICs and sensors without external regulators. |
| PLC Digital I/O Modules | Isolated Data Acquisition Front-End |
Use Scenario: Isolating digital inputs/outputs in modular PLC backplanes handling 24 V field-side signals. IC Role / Device Role / Timing Role: Provides channelized isolation for discrete I/O status and command signals with fail-safe default states. Use Value: Delivers reinforced insulation (UL/CSA/VDE) and 100 kV/µs CMTI - prevents noise coupling in noisy factory environments. |
Use Scenario: Isolating ADC interface lines (e.g., SPI clock/data) and powering isolated analog front-end (AFE) in HV battery monitoring. IC Role / Device Role / Timing Role: Transfers high-speed serial data across barrier while supplying clean 3.3 V to AFE and reference buffers. Use Value: Maintains 100 Mbps throughput with jitter <1 ns - preserves timing integrity for 16-bit+ SAR ADC sampling clocks. |
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 |
|---|---|---|---|
| SI88420BC-ISR | Same SOIC-16 package and Si8842x family, but single forward + single reverse channel (A1→B1, B2→A2) vs. SI88421BC-ISR's dual forward (A1→B1, A2→B2). | Suitable for bidirectional control loops (e.g., isolated UART) where reverse channel needed; SI88421BC-ISR preferred for dual unidirectional PWM. | Select SI88421BC-ISR when both isolated signals originate on primary side and terminate on secondary side. |
| ADUM6421A0A0BRIZ | Analog Devices part with integrated 500 mW DC-DC, 25 Mbps data rate, and 3750 VRMS isolation - lower power, lower speed, different topology (transformer-based). | Better suited for low-power sensor interfaces; lacks 5000 VRMS rating and AEC-Q100 qualification required for automotive traction systems. | Choose ADUM6421A0A0BRIZ only for non-automotive, low-noise, sub-1 W applications where 25 Mbps suffices. |
Compared with SI88421BC-ISR, SI88420BC-ISR offers bidirectional channel flexibility at identical isolation and thermal specs, while ADUM6421A0A0BRIZ trades isolation strength and automotive compliance for smaller footprint and simpler magnetics - making SI88421BC-ISR optimal for high-reliability, high-power, automotive-grade designs.
Availability
SI88421BC-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 SI88421BC-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.
The Si88xx family was engineered specifically for high-reliability isolated power and signal transfer in automotive, industrial, and energy infrastructure - combining robust capacitive isolation with flexible, efficient flyback DC-DC conversion.
FAQ
What is the maximum input voltage supported by the SI88421BC-ISR DC-DC converter?
The SI88421BC-ISR is designed for high-voltage primary-side operation up to 24 V. Its ESW driver and RSN current-sense input enable safe switching with external NMOS FETs, unlike Si882xx/3xx variants limited to ≤5.5 V input. The device requires VDDA ≤5.5 V, which may be supplied via VREGA and external NPN transistor if no compatible rail exists.
Does the SI88421BC-ISR support bidirectional data transmission?
No - the SI88421BC-ISR provides two unidirectional forward channels (A1→B1 and A2→B2). For bidirectional capability, consider SI88420BC-ISR (A1→B1 and B2→A2) or SI88422BC-ISR (A1→B1, A2→B2, B1→A1, B2→A2). Channel directionality is fixed per device variant and cannot be reconfigured.
What transformer is recommended for SI88421BC-ISR in a 24 V to 5 V application?
Skyworks validates UTB02205s (UMEC) and TA7788-AL (Coilcraft) for 24 V input to 5 V output. Both feature 3.0:1.0 turns ratio, ≤800 nH leakage inductance, 25 µH primary inductance, and 5 kVRMS isolation - matching SI88421BC-ISR's external-switch flyback requirements and EMI performance targets.
How does the SI88421BC-ISR achieve 5000 VRMS isolation without optocouplers?
The SI88421BC-ISR uses capacitive isolation with silicon dioxide dielectric barrier between transmitter and receiver, combined with reinforced insulation package construction (SOIC-16 wide-body, 8.3 mm creepage). Its DC-DC feedback is transmitted across the barrier digitally via encoded error signals - eliminating optocouplers while maintaining safety certification.
Is the SI88421BC-ISR pin-compatible with other Si8842x variants?
Yes - all Si8842x devices (SI88420/SI88421/SI88422) share identical SOIC-16 pinout per Figure 3 of the datasheet. Pin functions (e.g., ESW, RSN, VSNS, COMP) and package dimensions are identical; only channel directionality and internal routing differ, allowing drop-in replacement where signal flow matches.
SI88421BC-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
SI88421BC-ISR FAQ
1.How can I place an order for SI88421BC-ISR through Aetrix?
Please submit a Request for Quotation (RFQ) for SI88421BC-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 SI88421BC-ISR reliable?
The price and inventory of SI88421BC-ISR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI88421BC-ISR is usually 5 days.
3.What payment methods are accepted for SI88421BC-ISR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI88421BC-ISR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SI88421BC-ISR?
SI88421BC-ISR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SI88421BC-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 SI88421BC-ISR?
For technical support, including SI88421BC-ISR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI88421BC-ISR requirements.
6.How does Aetrix verify that SI88421BC-ISR is sourced from the original manufacturer or authorized distributors?
All SI88421BC-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 SI88421BC-ISR meets industry standards.
7.What is the process for return or replacement of SI88421BC-ISR?
All SI88421BC-ISR units undergo pre-shipment inspection (PSI). If there is an issue with SI88421BC-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 SI88421BC-ISR part is unused and in its original packaging.
Return procedure for SI88421BC-ISR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SI88421BC-ISR Tags
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