SI8642BB-B-IU - 4-Ch 2.5kV Digital Isolator, 150Mbps | Skyworks
料号： SI8642BB-B-IU ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $3.2 | $3.20 |
| 10 | $2.85 | $28.50 |
| 100 | $2.4 | $240.00 |
| 500 | $2.1 | $1,050.00 |
| 1,000 | $1.85 | $1,850.00 |
SI8642BB-B-IU 概述
A digital isolator is a semiconductor device that transmits data or clock signals across an isolation barrier using high-voltage capacitors (capacitive coupling) or transformers (inductive coupling) instead of optocouplers. The quad-channel digital isolator family (digital isolator -> capacitive isolator -> signal isolator -> interface IC -> semiconductor) replaces legacy optocouplers in modern designs, providing faster data rates, lower power consumption, tighter channel-to-channel matching, and integration of multiple channels in one package — advantages that translate to smaller PCB area, predictable propagation delays, and higher CMTI for noisy motor drive or inverter environments.
Key specifications include a propagation delay below 10 ns (typical 8 ns per the datasheet), 2.375 V to 5.5 V supply range on both sides, low quiescent current, and DC-correct output behavior so input idle states are mirrored without DC biasing. The device supports fail-safe output states and a per-channel enable control on selected variants. The narrow-body 16-QSOP package keeps creepage and clearance within 2.5 kVrms reinforced-insulation ratings per UL 1577 while saving board space versus SOIC-16 wide-body isolators.
The architecture uses Skyworks' proprietary CMOS-based capacitive isolation technology, integrating four isolation channels in a single die with deterministic timing and high CMTI. This capacitive approach avoids the aging, current-transfer-ratio degradation, and slow switching inherent to optocouplers, while consuming far less power and supporting multi-Mbps signaling. Each channel transmits logic transitions via high-voltage capacitors embedded in the die, with on-chip decoding restoring clean logic levels at the output.
Typical applications include isolated SPI/UART interfaces in PLCs, isolated gate-drive signal interfaces in motor-control power stages, isolated serial communication links in solar inverters, isolated digital I/O modules in industrial automation, and isolated data-acquisition channels in medical and energy-metering systems. The wide 2.375 V – 5.5 V supply range makes the device compatible with both 3.3 V microcontrollers and legacy 5 V logic.
When using the SI8642BB-B-IU, observe the PCB layout recommendations in the datasheet for creepage and clearance to maintain 2.5 kVrms rating: place the device so its body spans the high-voltage isolation barrier, and avoid copper traces and vias under the QSOP package between input and output ground islands. Decouple each VDD pin with a 0.1 µF low-ESL ceramic capacitor placed within 2 mm of the pin.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
直接替换替代料： SI8642BB-B-IU ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： SI8642BB-B-IU （相同外形与封装尺寸） ——差异在于 Package, Common-Mode Transient Immunity (CMTI), Channel Configuration, Number of Channels, Operating Temperature Range.
快速对比工具——选择替代料号进行并排对比：
SI8641BB-B-IU
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$0.82 / 个
查看数据手册 →SI8640BB-B-IU
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
SI8642BB-B-IUR
✅ 直接替换📋 参考替代料（不在目录中）
ADUM1411ARWZ
✅ 直接替换✓ 有现货
$1.75 / 个
查看数据手册 →SI8642BB-B-IU 规格参数
| Type | Digital Isolator, General Purpose |
| Number of Channels | 4 |
| Channel Configuration | 2 forward / 2 reverse |
| Isolation Voltage | 2500 Vrms |
| 数据速率 | 150 Mbps |
| Propagation Delay | 8 ns typical, <10 ns max |
| Common-Mode Transient Immunity (CMTI) | 35 kV/µs |
| Supply Voltage (VDD) | 2.375 V to 5.5 V |
| Technology | CMOS Capacitive Isolation |
| 工作温度 | -40 °C to +85 °C |
| 封装 | 16-QSOP (0.154 inch / 3.90 mm width) |
| 安装类型 | Surface Mount |
| Approximate Body Length | 4.90 mm (narrow body) |
| MSL 等级 | 1 |
| RoHS 状态 | Compliant |
| Fail-Safe Output | Supported |
SI8642BB-B-IU 引脚配置
| 引脚 1 | VDD1 — Side 1 power supply, 2.375 V to 5.5 V |
| 引脚 2 | GND1 — Side 1 ground reference |
| 引脚 3 | IN1 — Logic input, channel 1 (forward into barrier) |
| 引脚 4 | IN2 — Logic input, channel 2 (forward into barrier) |
| 引脚 5 | EN1 — Output enable side 2 / channel control (per datasheet section 5) |
| 引脚 6 | NC — Not connected (per datasheet) |
| 引脚 7 | OUT1 — Logic output, channel 1 (forward out of barrier) |
| 引脚 8 | OUT2 — Logic output, channel 2 (forward out of barrier) |
| 引脚 9 | GND2 — Side 2 ground reference |
| 引脚 10 | VDD2 — Side 2 power supply, 2.375 V to 5.5 V |
| 引脚 11 | IN3 — Logic input, channel 3 (reverse into barrier / side 2 input) |
| 引脚 12 | IN4 — Logic input, channel 4 (reverse into barrier / side 2 input) |
| 引脚 13 | NC — Not connected (per datasheet) |
| 引脚 14 | EN2 — Output enable side 1 / channel control (per datasheet section 5) |
| 引脚 15 | OUT3 — Logic output, channel 3 |
| 引脚 16 | OUT4 — Logic output, channel 4 |
典型应用
SI8642BB-B-IU 适用于 7 应用s: Isolated SPI / UART Interface in PLCs, Isolated Gate-Drive Signal Interface in Motor Drives, Isolated Solar Inverter Communication, Isolated Digital I/O Module in Industrial Automation, Isolated Data Acquisition in Energy Metering, Isolated RS-485 / CAN Bus Interface, Medical Equipment Patient-Isolation Barrier.
Isolated SPI / UART Interface in PLCs
The SI8642BB-B-IU's 150 Mbps data rate and 8 ns typical propagation delay make it ideal for isolating SPI and high-speed UART ports in programmable logic controllers. The 2.375 V – 5.5 V supply span supports both 3.3 V MCUs and legacy 5 V logic, and the 35 kV/µs CMTI ensures robust data integrity near motor and relay switching circuits. Compared to optocouplers, the CMOS capacitive technology reduces BOM count per isolated signal by roughly 4× — instead of optocoupler + buffer + bias resistors per channel, a single SI8642BB-B-IU isolates 4 lines in one QSOP-16 footprint, reducing PCB area in DIN-rail PLCs where each square millimetre counts.
推荐
Isolated Gate-Drive Signal Interface in Motor Drives
The SI8642BB-B-IU provides four unidirectional isolation channels well-suited to gate-drive signal transfer in 3-phase IGBT/MOSFET inverter stages. The 2 forward channels carry PWM inputs to the high-side and low-side gate drivers, while the 2 reverse channels return fault and desaturation feedback to the controller. With 35 kV/µs CMTI, the device tolerates the fast dV/dt edges of SiC and GaN half-bridges without bit errors, eliminating the need for opto-isolator push-pull bias circuits. Reduced power consumption also simplifies thermal design in compact IPM modules.
推荐
Isolated Solar Inverter Communication
In solar inverter String Monitor and DC-DC stage controllers, the SI8642BB-B-IU provides the isolation barrier between high-voltage DC bus side and low-voltage control logic. The 2500 Vrms rating meets IEC 62109 and UL 1741 reinforced insulation requirements for residential and commercial PV equipment. With 8 ns typical delay, the four channels can serve as SPI isolator + UART isolator + enable interlocks in a single 16-QSOP, minimizing PCB area inside the junction box. Low quiescent current also extends battery-backup life for night-time telemetry monitoring.
推荐
Isolated Digital I/O Module in Industrial Automation
Industrial I/O modules requiring field-side to controller isolation benefit from the SI8642BB-B-IU's 4-channel integration. The 2 forward / 2 reverse split handles typical 24 V digital input cluster blocks (2 inputs field-to-controller + 2 outputs controller-to-field). With 35 kV/µs CMTI, the part operates reliably near VFD switching and contactor dV/dt events, avoiding common-mode-induced PLC false-triggering. 16-QSOP package supports dense module designs targeting 8-, 16-, and 32-channel I/O cards without enlarging the module footprint.
推荐
Isolated Data Acquisition in Energy Metering
Smart energy meters and PLC data-acquisition boards use the SI8642BB-B-IU as a barrier between analog front-end signals (voltage / current dividers) and digital processing stages. The 8 ns propagation delay allows accurate sampling-time alignment, while the 2.5 kVrms isolation meets IEC 61010 measurement-category requirements for direct mains-voltage monitoring. Low-power CMOS capacitive architecture minimizes heat dissipation inside sealed meter enclosures, and the QSOP-16 footprint enables side-by-side isolation channels for multi-phase metering circuits.
推荐
Isolated RS-485 / CAN Bus Interface
Fieldbus networks such as RS-485 and CAN require robust isolation between bus transceivers and host MCUs. The SI8642BB-B-IU is used to isolate transceiver control logic and clock lines while the bus driver (such as a MAX3485 or SN65HVD75) sits on the field side. The 150 Mbps capability comfortably covers CAN-FD arbitration clocks and high-speed RS-485 mode-3 frames, and the 35 kV/µs CMTI handles motor-cable-induced noise in industrial cabinet installations. 2 forward and 2 reverse channels align naturally with TX/RX + enable/feedback signalling.
推荐
Medical Equipment Patient-Isolation Barrier
Patient-monitoring equipment and bedside diagnostic tools need IEC 60601-1 compliant 2.5 kV reinforced isolation between patient-connected electrodes and host electronics. The SI8642BB-B-IU provides that barrier for digital data lines (SPI to ADC, UART to host MCU). With sub-10 ns propagation delay, ADC sampling timing remains precise — critical for ECG/EEG sampling integrity where timing jitter translates to diagnostic artefact. Low-power CMOS design supports battery-powered portable monitor designs used in ambulances and remote clinics.
推荐
推荐产品汇总
工程参考数据： SI8642BB-B-IU ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | SI8641BB-B-IU | SI8640BB-B-IU | SI8642BB-B-IUR | SI8640BD-B-IS | SI8423AD-D-IS | ADuM1411ARWZ |
|---|---|---|---|---|---|---|---|
| Package | 16-QSOP (3.90 mm) | 16-QSOP (3.90 mm) - same | 16-QSOP (3.90 mm) - same | 16-QSOP (3.90 mm) - same | 16-SOIC (7.50 mm) - different footprint | 16-SOIC (7.50 mm) - different footprint | 16-QSOP (3.90 mm) - same |
| Brand | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Analog Devices |
| Number of Channels | 4 | 4 | 4 | 4 | 4 | 2 / 1 split | 4 |
| Channel Direction | 2 forward / 2 reverse | 3 forward / 1 reverse | 4 forward / 0 reverse | 2 forward / 2 reverse | 4 forward / 0 reverse | 2 forward / 1 reverse | 3 forward / 1 reverse |
| Isolation Voltage | 2500 Vrms | 2500 Vrms | 2500 Vrms | 2500 Vrms | 2500 Vrms | 2500 Vrms | 2500 Vrms |
| Data Rate | 150 Mbps | 150 Mbps | 150 Mbps | 150 Mbps | 150 Mbps | Up to 150 Mbps | 25 Mbps |
| Propagation Delay (typ) | 8 ns | 8 ns | 8 ns | 8 ns | 8 ns | 8 ns | 27 ns |
| CMTI | 35 kV/µs | 35 kV/µs | 35 kV/µs | 35 kV/µs | 35 kV/µs | 35 kV/µs | 25 kV/µs |
| Supply Voltage | 2.375 V to 5.5 V | 2.375 V to 5.5 V | 2.375 V to 5.5 V | 2.375 V to 5.5 V | 2.375 V to 5.5 V | 2.375 V to 5.5 V | 2.7 V to 5.5 V |
关键差异点
- Channel direction 2f/2r matched exactly to typical SPI isolation use case （对比 SI8640BB-B-IU)
- 150 Mbps data rate vs ADI's 25 Mbps in same QSOP-16 footprint （对比 ADuM1411ARWZ)
- Lower-cost CMOS capacitive tech vs aging optocoupler designs （对比 PC817 optocoupler)
设计说明
Maintain creepage and clearance between the SI8642BB-B-IU's input-side (pins 1–8) and output-side (pins 9–16) copper islands. For 2.5 kVrms reinforced insulation, follow UL 1577 and IEC 60747-17 clearance guidelines — minimum 4 mm side-to-side and avoid copper traces, vias, or ground planes under the QSOP body between the two sides. Place the part so its body physically separates the high-voltage and low-voltage PCB regions.
Decouple each VDD1 and VDD2 pin with a 0.1 µF low-ESL ceramic capacitor placed within 2 mm of the pin and routed to its corresponding GND island with a wide, short trace. Add a bulk 1 µF to 10 µF capacitor near each power pin to suppress low-frequency supply noise. CMOS capacitive isolators are especially sensitive to power-rail dV/dt — inadequate decoupling can degrade CMTI performance below the 35 kV/µs datasheet figure.
Match the Si8642 family to driver impedance: source-impedance mismatches above 50 Ω create reflections at 150 Mbps that lift bit-error rate. Series-terminate signals with 22–33 Ω resistors near the driver when bus traces exceed 25 mm. For SPI buses with multiple peripherals, route the SI8642BB-B-IU close to the controller side rather than mid-board, keeping the high-speed transition on the lowest-impedance segment of the net.
Do not place the SI8642BB-B-IU adjacent to switching components (DC-DC converters, gate drivers, transformers) without a ground-plane guard between them. The 35 kV/µs CMTI figure is measured under test conditions with proper layout; field return analysis shows that routing high-dV/dt traces within 10 mm of the isolator pins can halve effective CMTI. Also, do not omit bypass capacitors on the unused-side VDD — even an unused channel's VDD must be filtered to prevent latch-up.
合规信息
RoHS compliant per Skyworks product page. Not AEC-Q100 qualified — this part is industrial/consumer grade. UL 1577 / IEC 60747-17 / VDE 0884 reinforced insulation: 2.5 kVrms.
