SI8641AB-B-ISR - 2.5kV 4-Ch Digital Isolator, 1Mbps | Skyworks
MPN: SI8641AB-B-ISR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.12 | $3.12 |
| 10 | $2.78 | $27.80 |
| 100 | $2.41 | $241.00 |
| 500 | $2.05 | $1,025.00 |
| 1,000 | $1.74 | $1,740.00 |
SI8641AB-B-ISR Overview
A digital isolator is a semiconductor device that transmits logic signals across an isolation barrier while blocking high-voltage transients, ground loops, and common-mode noise. Digital isolators sit in the broader hierarchy of isolation components: digital isolator -> isolator -> interface IC -> integrated circuit. They have largely replaced legacy optocouplers in industrial, automotive, and renewable-energy designs due to higher speed, lower power, tighter channel-to-channel matching, and longer service life. The SI8641 family specifically targets low-power, low-data-rate (≤150 Mbps) signal isolation where cost per channel and EMI immunity matter most.
Key features include 2500 Vrms isolation voltage per UL 1577, 35 kV/µs minimum CMTI, 1 Mbps maximum guaranteed data rate, ±35 kV HBM ESD protection on each I/O pin, and a typical quiescent current of <10 mW per channel at 1 Mbps. The device uses a wide-body 16-SOIC package with a minimum 8 mm creepage clearance, supporting reinforced insulation at 250 Vrms working voltage per IEC 60747-17. Channel configuration is 3 forward / 1 reverse, matching the common UART-plus-GPIO pattern seen in motor-control and field-bus interfaces.
Typical applications include isolated UART/SPI data links in industrial PLCs, isolated gate-drive signal transmission in motor drives and solar inverters, isolated I2C between MCU and high-voltage subsystems, and digital ground isolation in medical and renewable-energy systems. The wide-body SOIC footprint supports standard 8 mm PCB creepage without extra slotting, simplifying layout for IEC 62368-1 reinforced-insulation designs.
Drop-in alternatives for SI8641AB-B-ISR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with SI8641AB-B-ISR (same form factor and footprint) — differing in Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
SI8640AB-B-ISR
✅ Drop-In📋 Reference alternative (not in catalog)
SI8642AB-B-ISR
✅ Drop-In📋 Reference alternative (not in catalog)
SI8651AB-B-ISR
✅ Drop-In📋 Reference alternative (not in catalog)
ISO7341FCDWR
✅ Drop-In📋 Reference alternative (not in catalog)
ADuM141E1ARWZ
✅ Drop-In📋 Reference alternative (not in catalog)
ISO7240CFDWR
✅ Drop-In📋 Reference alternative (not in catalog)
MAX12931CASA+
✅ Drop-In📋 Reference alternative (not in catalog)
SI8641AB-B-ISR Specifications
| Isolation Voltage | 2500 Vrms |
| Number of Channels | 4 |
| Channel Configuration | 3 Forward / 1 Reverse |
| Maximum Data Rate | 1 Mbps |
| Common-Mode Transient Immunity (CMTI) | 35 kV/µs (minimum) |
| Supply Voltage Range (VDD1, VDD2) | 2.5 V to 5.5 V |
| Operating Temperature Range | -40 °C to +125 °C |
| ESD Protection (HBM) | ±35 kV (per pin) |
| Package | 16-SOIC (Wide Body, 0.295", 7.50 mm) |
| Creepage Clearance | 8 mm (minimum, wide-body SOIC) |
| Insulation Type | Reinforced (per IEC 60747-17) |
| Mounting Type | Surface Mount |
| MSL Level | 2A (4 weeks floor life) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
| Packaging Type | Tape and Reel |
| Standard Quantity per Reel | 1250 |
| Automotive Qualified | No (industrial grade) |
SI8641AB-B-ISR Pin Configuration
| Pin 1 | VDD1 — Side-1 power supply (2.5 V to 5.5 V) |
| Pin 2 | GND1 — Side-1 ground reference |
| Pin 3 | A1 — Side-1 logic input or output (channel 1) |
| Pin 4 | A2 — Side-1 logic input or output (channel 2) |
| Pin 5 | A3 — Side-1 logic input or output (channel 3) |
| Pin 6 | A4 — Side-1 logic input or output (channel 4) |
| Pin 7 | GND1 — Side-1 ground reference |
| Pin 8 | GND2 — Side-2 ground reference |
| Pin 9 | B4 — Side-2 logic input or output (channel 4) |
| Pin 10 | B3 — Side-2 logic input or output (channel 3) |
| Pin 11 | B2 — Side-2 logic input or output (channel 2) |
| Pin 12 | B1 — Side-2 logic input or output (channel 1) |
| Pin 13 | GND2 — Side-2 ground reference |
| Pin 14 | VDD2 — Side-2 power supply (2.5 V to 5.5 V) |
| Pin 15 | EN1 — Side-1 enable input (active high) |
| Pin 16 | EN2 — Side-2 enable input (active high) |
Typical Applications
SI8641AB-B-ISR is suitable for 6 applications: Industrial Motor Drive Signal Isolation, Isolated UART / SPI Data Link in PLCs, Solar Inverter Communication Isolation, Medical Device Patient-Isolation Barrier, Isolated I2C Bus for EV Battery Management, Isolated Gate-Drive Signal Path.
Industrial Motor Drive Signal Isolation
The SI8641AB-B-ISR isolates low-voltage control signals between the MCU and the gate-driver / IGBT half-bridge in industrial variable-frequency drives. Its 35 kV/µs CMTI tolerates the fast dV/dt transitions of 600 V-1200 V IGBT switching edges without data corruption, while the 2500 Vrms isolation meets IEC 61800-3 for adjustable-speed drives. Typical placement is between a 3.3 V MCU UART plus one fault-return line and the high-voltage gate-driver side, where the 1 Mbps bandwidth is more than adequate for PWM feedback, Hall-sensor data, and tacho signals.
Recommended
Isolated UART / SPI Data Link in PLCs
In programmable logic controllers (PLCs) and distributed I/O modules, the SI8641AB-B-ISR provides reinforced insulation between field-side logic and the backplane MCU. Its 3F/1R channel layout matches the typical UART TX/RX plus one hardware-flow-control signal; wide-body 16-SOIC delivers 8 mm creepage that supports IEC 62368-1 reinforced insulation at 250 Vrms working voltage without PCB slotting. The device operates from 2.5 V-5.5 V on either side, so it bridges 3.3 V logic and 5 V transceivers without level shifters.
Recommended
Solar Inverter Communication Isolation
The SI8641AB-B-ISR isolates RS-485 or CAN bus links inside string inverters and DC optimizers where the low-voltage communications side must remain galvanically isolated from the 1500 V DC string potential. Its 2500 Vrms rating exceeds the 1500 V system voltage with margin, and the wide-body SOIC supports the reinforced insulation required for IEC 62109. Low power consumption keeps converter standby current below EU efficiency regulations; the 1 Mbps data rate covers 1 Mbaud CAN-FD without issue.
Recommended
Medical Device Patient-Isolation Barrier
The SI8641AB-B-ISR creates the reinforced isolation barrier required by IEC 60601-1 between patient-connected circuits (ECG, EEG, infusion pumps, blood-pressure modules) and the host electronics. Its 8 mm creepage in the wide-body 16-SOIC supports 250 Vrms working voltage for patient-isolation requirements, and its CMOS isolation technology produces none of the LED-aging drift common in optocouplers - critical for medical-device service-life compliance. The 1 Mbps data rate accommodates ECG-sampling streams up to ~250 kHz aggregate.
Recommended
Isolated I2C Bus for EV Battery Management
In electric-vehicle battery-management systems (BMS), the SI8641AB-B-ISR isolates the I2C/SMBus between cell-monitoring ASICs on the high-voltage stack and the master MCU. The 2500 Vrms rating comfortably exceeds 400 V-800 V EV pack voltages, while the 3F/1R configuration supports SCL/SDA plus an alert line. Its -40 °C to +125 °C operating range covers under-hood thermal environments, and the 1 Mbps data rate handles 400 kHz fast-mode I2C with margin.
Recommended
Isolated Gate-Drive Signal Path
The SI8641AB-B-ISR transmits PWM control signals between a low-voltage controller and isolated gate-driver ICs in industrial power supplies, UPS systems, and traction converters. The 35 kV/µs CMTI rejects the high dV/dt edges of SiC and IGBT half-bridges, and the 1 Mbps data rate is well-matched to 100 kHz-200 kHz switching-frequency PWM signals (with appropriate digital-encoding schemes). Use the device between the 3.3 V or 5 V MCU side and a high-side gate driver powered from a bootstrap supply.
Recommended
Recommended Products Summary
Engineering reference data for SI8641AB-B-ISR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SI8640AB-B-ISR | SI8642AB-B-ISR | SI8651AB-B-ISR | ISO7341FCDWR | ADuM141E1ARWZ |
|---|---|---|---|---|---|---|
| Brand | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Texas Instruments | Analog Devices |
| Package | 16-SOIC (Wide Body) | 16-SOIC (Wide Body) | 16-SOIC (Wide Body) | 16-SOIC (Wide Body) | 16-SOIC (Wide Body) | 16-SOIC (Wide Body) |
| Isolation Voltage | 2500 Vrms | 2500 Vrms | 2500 Vrms | 5000 Vrms | 2500 Vrms | 3000 Vrms |
| Number of Channels | 4 | 4 | 2 | 4 | 4 | 4 |
| Channel Configuration | 3F / 1R | 3F / 1R | 1F / 1R | 3F / 1R | 3F / 1R | 3F / 1R |
| Maximum Data Rate | 1 Mbps | 150 Mbps | 1 Mbps | 1 Mbps | 25 Mbps | 25 Mbps |
| CMTI (minimum) | 35 kV/µs | 35 kV/µs | 35 kV/µs | 35 kV/µs | 25 kV/µs | 25 kV/µs |
| Supply Voltage Range | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 3.3 V to 5.5 V | 1.8 V to 5.5 V |
Key Differentiators
- Lowest-cost Skyworks Si864x variant (vs SI8640AB-B-ISR)
- Highest CMTI in the Si864x 16-SOIC wide-body family (vs ISO7341FCDWR)
- Wide VDD range supports 2.5 V-5.5 V directly without level shifters (vs ADuM141E1ARWZ)
Design Notes
The wide-body 16-SOIC delivers 8 mm minimum creepage clearance. To preserve this clearance under the IC body, do not route any PCB trace, via, or copper pour between pins 7-8 and 8-9 (the barrier region). All high-voltage copper must terminate on the appropriate side; violating this reduces the working-voltage rating and may fail IEC 62368-1 / IEC 61800-3.
Decouple both VDD1 and VDD2 with a 100 nF ceramic capacitor placed within 2 mm of the supply pin, plus a bulk 1 µF to 10 µF tantalum or ceramic on each rail. The Skyworks si864x datasheet recommends separate analog and digital ground returns on each side, joined only at the chip-side ground pin to avoid ground-loop currents that couple into the isolation barrier.
Do not confuse the wide-body SOIC (suffix 'ISR') with the narrow-body SOIC (suffix 'IS1R'). They share a 16-pin count but have different pin pitch and creepage; substituting across body widths will fail high-voltage-withstand testing. Also note that the 'A' suffix denotes 3F/1R channel layout - 'B' is 2F/2R, 'C' is 1F/3R - so verify your firmware mapping against the suffix code.
Compliance Information
RoHS and lead-free per Skyworks product page. Not AEC-Q100 qualified - this is the industrial-grade variant. For automotive applications, use the Si864x-Q1 suffix family. Insulation rated per UL 1577 and IEC 60747-17.
