SI8645BA-B-IU - 4-Ch 1kV Digital Isolator, 150Mbps | Skyworks
N.º da peça: SI8645BA-B-IU ✓ Ativo| Qtd. | Preço unitário | Total |
|---|---|---|
| 1 | $2.18 | $2,18 |
| 10 | $1.96 | $19,60 |
| 100 | $1.74 | $174,00 |
| 500 | $1.52 | $760,00 |
| 1.000 | $1.34 | $1.340,00 |
SI8645BA-B-IU Visão geral
A digital isolator is a semiconductor device that transfers logic-level signals across an isolation barrier using capacitive, inductive (transformer), or giant-magnetoresistive (GMR) coupling while blocking DC and high-voltage transients. Digital isolators sit within the broader hierarchy of interface ICs > isolators > signal-conditioning ICs > integrated circuits. They replace legacy optocouplers in applications that need high speed, low power, high CMTI, and stable performance over temperature and device lifetime.
Key features of the SI8645BA-B-IU include four unidirectional channels with the same input/output direction (4/0 channel configuration, BA variant), 2.5 V to 5.5 V wide VDD range on both sides for level translation, low power consumption typical of Skyworks' Si86xx family, and 8 ns maximum propagation delay. The CMOS-based isolation barrier delivers stable operating parameters across wide temperature ranges and throughout device service life, easing design-in and yielding highly uniform performance.
The device uses Skyworks' proprietary CMOS isolation technology with on-chip capacitive isolation barriers, providing robust rejection of common-mode transients up to 35 kV/µs. This makes it suitable for noisy industrial environments where fast switching transients can corrupt data transmission across the isolation barrier.
Typical applications include isolated SPI/UART interfaces between microcontrollers and peripherals, industrial fieldbus isolation (RS-485, CAN, Profibus), isolated gate driver signal paths for power converters, and battery management isolation in lithium-ion battery packs. The 4-channel, same-direction configuration is particularly useful when the designer needs to transmit four parallel control or data signals across the isolation barrier.
When designing with this part, ensure that decoupling capacitors are placed close to each VDD pin and that the PCB layout provides adequate creepage and clearance per the application's safety standard (e.g., IEC 60747-17, UL 1577). For best CMTI performance, keep the isolation barrier free of nearby high-dV/dt traces and provide a solid ground return on each side.
This page synthesizes distributor pricing, drop-in alternative listings, and practical design notes not found in the standalone manufacturer datasheet, giving procurement and design engineers a single reference for sourcing the SI8645BA-B-IU.
Alternativas drop-in para SI8645BA-B-IU — mesmo encapsulamento, compatível pino a pino. Peças de encapsulamento diferente que exigem retrabalho na PCB são excluídas.
Variantes desta série
Modelos da mesma série compatíveis como drop-in com SI8645BA-B-IU (mesmo formato e footprint) — diferindo em Channel Configuration, Package, Common-Mode Transient Immunity (CMTI), Data Rate, Operating Temperature.
Ferramenta de comparação rápida — selecione peças alternativas para comparação lado a lado:
SI8645BA-B-IUR
✅ Drop-In✓ Em estoque
$1.62 / unidade
Ver ficha técnica →SI8642BB-B-IU
✅ Drop-In✓ Em estoque
$1.85 / unidade
Ver ficha técnica →SI8645BA-B-IU Especificações
| Isolation Type | Digital Isolator (CMOS capacitive) |
| Number of Channels | 4 |
| Channel Configuration | 4/0 (all same direction, BA variant) |
| Isolation Voltage Rating | 1000 Vrms |
| Taxa de dados | 150 Mbps |
| Common-Mode Transient Immunity (CMTI) | 35 kV/µs |
| Propagation Delay (max) | 8 ns |
| Supply Voltage (VDD) | 2.5 V to 5.5 V |
| Encapsulamento | 16-pin QSOP / SSOP (0.154", 3.90 mm width) |
| Tipo de montagem | Surface Mount |
| Temperatura de operação | -40 C to +125 C (industrial) |
| Status RoHS | Compliant |
| Lead-Free | Yes |
| Technology | CMOS capacitive isolation barrier |
| Direction | Unidirectional (forward) |
Configuração de pinos do SI8645BA-B-IU
| Pino 1 | VDD1 — Side 1 supply voltage (2.5 V to 5.5 V) |
| Pino 2 | GND1 — Side 1 ground |
| Pino 3 | A1 — Side 1 input, channel 1 (forward) |
| Pino 4 | A2 — Side 1 input, channel 2 (forward) |
| Pino 5 | A3 — Side 1 input, channel 3 (forward) |
| Pino 6 | A4 — Side 1 input, channel 4 (forward) |
| Pino 7 | GND1 — Side 1 ground (alternate pin) |
| Pino 8 | GND1 — Side 1 ground (alternate pin) |
| Pino 9 | GND2 — Side 2 ground (alternate pin) |
| Pino 10 | GND2 — Side 2 ground (alternate pin) |
| Pino 11 | B4 — Side 2 output, channel 4 (forward) |
| Pino 12 | B3 — Side 2 output, channel 3 (forward) |
| Pino 13 | B2 — Side 2 output, channel 2 (forward) |
| Pino 14 | B1 — Side 2 output, channel 1 (forward) |
| Pino 15 | GND2 — Side 2 ground |
| Pino 16 | VDD2 — Side 2 supply voltage (2.5 V to 5.5 V) |
Aplicações típicas
SI8645BA-B-IU é adequado para 6 aplicaçãos: Isolated SPI/UART Communication, Industrial Fieldbus Isolation (RS-485 / CAN), Isolated Gate Driver Signal Path, Battery Management System (BMS) Isolation, Medical Device Signal Isolation, Isolated I/O Module for PLCs.
Isolated SPI/UART Communication
The SI8645BA-B-IU isolates SPI or UART signals between a host microcontroller and a peripheral across a 1 kVrms barrier. The 150 Mbps data rate and 8 ns propagation delay comfortably handle SPI clocks above 50 MHz and UART baud rates up to several Mbaud without adding meaningful latency to the communication link. The 4-channel, all-forward configuration maps cleanly to SCLK, MOSI, CS, and a unidirectional control GPIO. Placed between the host MCU and the isolated peripheral IC, the part replaces bulky optocouplers and shrinks the BOM while improving noise immunity and reliability over device lifetime.
Recomendado
Industrial Fieldbus Isolation (RS-485 / CAN)
The SI8645BA-B-IU isolates RS-485, CAN, or Profibus transceivers from their host controller across a 1 kVrms functional isolation barrier. The 35 kV/us CMTI rating rejects fast common-mode transients from motor drives and switching power converters on the bus side, preventing data corruption in noisy industrial environments. Four channels provide TX, RX, DE/RE control, and a fault signal back to the controller. Compared to optocouplers, the CMOS capacitive barrier delivers stable timing over temperature, lower power, and longer service life - critical for factory automation equipment.
Recomendado
Isolated Gate Driver Signal Path
The SI8645BA-B-IU transmits PWM gate-drive control signals from a low-voltage controller to a high-side gate driver IC in IGBT or SiC inverter stages. With 8 ns propagation delay and matched channel-to-channel timing, the device preserves the dead-time and shoot-through protection schemes designed into the controller. The 35 kV/us CMTI is critical here because the high-side switch node generates fast dV/dt edges that would couple into lower-rated isolators. Choose the Si8640 (2.5 kVrms) or Si8641 (5 kVrms) instead when the application requires reinforced isolation for safety.
Recomendado
Battery Management System (BMS) Isolation
The SI8645BA-B-IU isolates communication between a battery-pack microcontroller (master) and the slave monitoring ICs across a 1 kVrms barrier in lithium-ion battery packs. The four forward channels carry clock, data, control, and a wake-up signal from the master to the slave side, while keeping the high-voltage battery stack safely separated from the low-voltage system. Low power consumption suits the always-on battery-monitoring use case, and the wide -40 C to +125 C temperature range handles under-hood and chassis-mounted packs. For 800V EV traction packs, choose the Si8641 (5 kVrms) for reinforced isolation instead.
Recomendado
Medical Device Signal Isolation
The SI8645BA-B-IU provides functional isolation between patient-connected analog front-end circuitry and the digital controller in medical devices such as patient monitors, infusion pumps, and diagnostic instruments. The 1 kVrms rating meets IEC 60601-1 functional isolation requirements; for reinforced isolation the Si8641 (5 kVrms) is required. The CMOS capacitive barrier eliminates optocoupler aging concerns, delivering stable propagation delay and pulse-width distortion over the device lifetime. The 4-channel, same-direction configuration suits single-direction analog front-end control signals.
Recomendado
Isolated I/O Module for PLCs
The SI8645BA-B-IU isolates digital input or output channels on PLC and DCS I/O modules from the backplane logic, providing 1 kVrms functional isolation per channel group. The four forward channels carry 24V digital inputs through the barrier to the logic-side optocoupler-replacement interface, while the CMOS design eliminates the LED-aging issues of legacy optocouplers. Wide 2.5 V to 5.5 V supply range on both sides supports 3.3 V and 5 V logic, and the 150 Mbps speed headroom ensures the part is not the limiting factor in fast I/O update applications.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para SI8645BA-B-IU — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | SI8645BA-B-IUR | SI8642BB-B-IU | SI8641BD-B-ISR |
|---|---|---|---|---|
| Brand | Skyworks | Skyworks | Skyworks | Skyworks |
| Package | QSOP-16 (0.154", 3.90 mm) | QSOP-16 (0.154", 3.90 mm) - same | QSOP-16 (0.154", 3.90 mm) - same | SOIC-16W (300 mil, 7.50 mm) - wider body, NOT pin-compatible |
| Isolation Voltage | 1000 Vrms | 1000 Vrms | 1000 Vrms | 5000 Vrms |
| Number of Channels | 4 | 4 | 4 | 4 |
| Channel Direction | 4 forward (4/0) | 4 forward (4/0) | 2 forward + 2 reverse (2/2) | 3 forward + 1 reverse (3/1, BD variant) |
| Data Rate | 150 Mbps | 150 Mbps | 150 Mbps | 150 Mbps |
| Propagation Delay (max) | 8 ns | 8 ns | 8 ns | 8 ns |
| CMTI | 35 kV/µs | 35 kV/µs | 35 kV/µs | 35 kV/µs |
| Supply Voltage | 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 |
Principais diferenciais
- 1 kVrms functional isolation in compact QSOP-16 package (vs SI8641BD-B-ISR)
- 150 Mbps data rate and 8 ns propagation delay (vs Lower-speed Si86xx variants (1 Mbps / 25 Mbps grades))
- 35 kV/us CMTI for noisy industrial environments (vs Optocoupler-based isolation (typical CMTI 10-25 kV/us))
Notas de projeto
Maintain adequate creepage and clearance across the isolation barrier per IEC 60747-17 / UL 1577. For the QSOP-16 Si8645, the package body itself defines the minimum 1 kVrms clearance when laid out with no copper beneath the package. Route the high-side and low-side PCB traces on separate layers and do not place any signal or power trace under the device package - the capacitive isolation barrier couples energy through the package body.
Place a 0.1 uF ceramic bypass capacitor within 2 mm of each VDD pin (VDD1 and VDD2) and a 1 uF to 10 uF bulk capacitor close to each supply. Both supply domains are independent; proper decoupling on each side is required to maintain low supply ripple and to avoid data corruption from VDD transients. The 2.5 V to 5.5 V range allows direct connection to 3.3 V or 5 V rails without level shifters.
Keep input and output traces matched in length when transmitting clock or high-speed data signals. The 8 ns propagation delay is matched channel-to-channel within a few nanoseconds, but PCB trace mismatch can add skew. For SPI, route SCLK and MOSI with matched lengths and place the isolator close to the connector or barrier edge to minimize stub lengths. Avoid routing noisy signals (high dV/dt switch-node traces) parallel to and close to the isolation barrier.
Do not assume that any Skyworks Si864x QSOP-16 variant is drop-in compatible with the Si8645: the BA, BB, BD, and BE suffixes indicate different channel-direction configurations (4/0, 2/2, 3/1, 1/3). Swapping a 4-forward part for a 2/2 variant will reverse two channels and silently break the design. Verify the channel direction code in the ordering information section of the datasheet before substituting. Also do not exceed 5.5 V on either VDD supply, or the device may suffer permanent damage.
Informações de conformidade
RoHS compliance confirmed per Skyworks product page and DigiKey listing. The Si8645 is not AEC-Q100 qualified; the Si8645BA-B-IUR variant or Si864x-Q1 automotive grades should be selected for automotive applications. REACH, halogen-free, and conflict-mineral statements not located in the provided data and are marked unknown.
