SI8645BA-B-IUR - 4-Ch 1kVrms Digital Isolator, 150Mbps | Skyworks
Артикул: SI8645BA-B-IUR ✓ Активен| Кол-во | Цена за ед. | Итого |
|---|---|---|
| 1 | $3.38 | $3,38 |
| 10 | $2.96 | $29,60 |
| 100 | $2.41 | $241,00 |
| 500 | $1.93 | $965,00 |
| 1.000 | $1.62 | $1.620,00 |
SI8645BA-B-IUR Обзор
A digital isolator is a semiconductor device that transfers data across an galvanically-isolated barrier using high-frequency CMOS signaling through on-chip transformers or capacitive barriers instead of optocouplers' LED-phototransistor links. Compared to legacy optocouplers, CMOS digital isolators deliver up to 10x faster data rates, 5x lower power consumption, tighter channel-to-channel timing skew, and superior CMTI. Within the signal-chain hierarchy, the SI8645 sits under: digital isolator -> isolation IC -> interface IC -> integrated circuit.
Key features include headroom: 2.5 V to 5.5 V wide-side supply range on both sides of the barrier (allowing level translation between 3.3 V and 5 V domains), default-high fail-safe output state that drives the output logic-high if the input side loses power, Schmitt-trigger inputs for slow/noisy edges, and a propagation delay of approximately 10 ns typical with sub-ns skew. The part integrates four unidirectional isolation channels configured per the "BA" pinout ordering.
Architecturally, the SI8645 uses Skyworks' proprietary CMOS isolation technology with on-chip RF carriers and miniature transformers, achieving 1 kVrms isolation in a sub-2 mm-tall QSOP-16 package. Typical power consumption is below 6 mW per channel at 150 Mbps, an order-of-magnitude improvement over optocouplers at the same throughput.
Typical applications include industrial field-bus isolation (RS-485, RS-232, CAN, SPI), microcontroller I/O isolation, isolated ADC/DAC signal paths, motor-control gate-driver signal isolation, and isolated power-supply feedback paths. The wide 2.5-5.5 V supply on both sides lets it bridge logic domains without extra level-shifters.
When designing with this part, observe the layout guidance from the datasheet: route the isolated ground returns directly under the IC, place bypass capacitors on each VDD pin within 2 mm, and keep data traces matched to avoid skew. The fail-safe default-high output must be considered in any system where loss of input power must NOT cause a false enable signal on the isolated side.
This page consolidates distributor pricing, drop-in alternatives, and PCB-layout guidance not found in the manufacturer datasheet, providing engineers a faster path to a drop-in design decision.
Аналоги без доработки для SI8645BA-B-IUR — тот же корпус, pin-to-pin совместимость. Компоненты в других корпусах, требующие переработки PCB, исключены.
Варианты в этой серии
Модели той же серии, совместимые без доработки с SI8645BA-B-IUR (тот же форм-фактор и посадочное место) — отличается по Package, Common-Mode Transient Immunity (CMTI), Channel Configuration, MSL Level, Operating Temperature Range.
Инструмент быстрого сравнения — выберите альтернативные компоненты для сравнения бок о бок:
SI8645BA-B-IU
✅ Прямая замена✓ В наличии
$1.34 / шт.
Открыть даташит →SI8645BB-B-IUR
✅ Прямая замена📋 Справочный аналог (нет в каталоге)
SI8642BB-B-IU
✅ Прямая замена✓ В наличии
$1.85 / шт.
Открыть даташит →SI8641BD-B-ISR
✅ Прямая замена✓ В наличии
$1.62 / шт.
Открыть даташит →SI8640BD-B-IS
✅ Прямая замена✓ В наличии
$1.89 / шт.
Открыть даташит →SI8645BA-B-IUR Характеристики
| Isolation Rating | 1 kVrms |
| Number of Channels | 4 |
| Channel Configuration | 4/0 (unidirectional) |
| Скорость передачи данных | 150 Mbps (max) |
| Common-Mode Transient Immunity (CMTI) | 35 kV/µs (min) |
| Supply Voltage Range (VDD1, VDD2) | 2.5 V to 5.5 V |
| Output Default State | High (fail-safe high) |
| Input Type | Schmitt-trigger CMOS |
| Диапазон рабочих температур | -40°C to +125°C (industrial) |
| Корпус | QSOP-16 / SSOP-16 (0.154", 3.90 mm body width) |
| Тип монтажа | Surface Mount |
| Packaging | Tape & Reel (2500 pcs/reel) |
| Статус RoHS | Compliant |
Конфигурация выводов SI8645BA-B-IUR
| Контакт 1 | VDD1 — Power supply, side 1 (input side) |
| Контакт 2 | GND1 — Ground reference, side 1 |
| Контакт 3 | INA — Digital input, channel A (side 1) |
| Контакт 4 | INB — Digital input, channel B (side 1) |
| Контакт 5 | INC — Digital input, channel C (side 1) |
| Контакт 6 | IND — Digital input, channel D (side 1) |
| Контакт 7 | NC — Not connected (per datasheet) |
| Контакт 8 | GND1 — Ground reference, side 1 (alternate) |
| Контакт 9 | GND2 — Ground reference, side 2 (output side) |
| Контакт 10 | OUTD — Digital output, channel D (side 2) |
| Контакт 11 | OUTC — Digital output, channel C (side 2) |
| Контакт 12 | OUTB — Digital output, channel B (side 2) |
| Контакт 13 | OUTA — Digital output, channel A (side 2) |
| Контакт 14 | NC — Not connected (per datasheet) |
| Контакт 15 | GND2 — Ground reference, side 2 (alternate) |
| Контакт 16 | VDD2 — Power supply, side 2 (output side) |
Типичное применение
SI8645BA-B-IUR подходит для 7 применениеs: Industrial RS-485 / Fieldbus Isolation, Isolated SPI Bus for ADC / DAC, Isolated Gate-Driver Signal Path, Isolated CAN-FD Bus Node, Isolated I2C Bus (Bidirectional Channel Use), Battery-Management System (BMS) Isolation, Isolated Digital I/O for PLCs.
Industrial RS-485 / Fieldbus Isolation
The SI8645BA-B-IUR's 1 kVrms isolation, 35 kV/µs CMTI, and 150 Mbps throughput make it an excellent match for isolating RS-485 transceivers on Modbus, PROFIBUS, and DMX512 industrial fieldbuses. Its 4-channel count covers TX, RX, RE/DE, and a fault-line signal cleanly. The 2.5-5.5 V dual-side range lets it bridge 3.3 V MCU UARTs to 5 V bus-side transceivers without extra level shifters, and its Schmitt-trigger inputs tolerate the slow, noisy edges typical of long cable runs. Power consumption stays below 6 mW per channel at full 150 Mbps, easing thermal budgets in dense PLC designs.
Рекомендуется
Isolated SPI Bus for ADC / DAC
For precision data-acquisition systems, the SI8645BA-B-IUR isolates the SPI bus between an MCU and an ADC or DAC, breaking ground loops that would otherwise inject noise into the analog front end. The 150 Mbps data rate comfortably exceeds the requirements of 24-bit sigma-delta converters running at full sample rate, while the 35 kV/µs CMTI protects the digital side from the high-dV/dt switching nodes of motor drives or solenoids in mixed-signal systems. The fail-safe default-high output prevents a false chip-select assertion if the controller side loses power, a critical safety feature for industrial instrumentation.
Рекомендуется
Isolated Gate-Driver Signal Path
In motor-drive and inverter designs, the SI8645BA-B-IUR carries the PWM logic signals from the low-voltage MCU to the high-side gate driver, providing the 1 kVrms barrier required to protect the controller from the high-voltage bus. The 35 kV/µs CMTI is well-matched to the dV/dt stress seen at the gate-driver outputs of SiC and IGBT switching stages, preventing the isolator from latch-up or data corruption. The four channels let the designer isolate three PWM phases plus a fault feedback in one IC, simplifying the BOM.
Рекомендуется
Isolated CAN-FD Bus Node
The SI8645BA-B-IUR isolates a CAN-FD bus node at 1 kVrms while easily supporting the 5 Mbps peak rate of CAN-FD frames. The 35 kV/µs CMTI rejects the transient stress present on the bus stubs of electric-vehicle and industrial CAN networks, preventing bit-error spikes during fault conditions. Pair the isolator with a 3.3 V CAN transceiver on the bus side and the MCU UART on the controller side; the dual 2.5-5.5 V supply lets either side run independently of the other. Industrial temperature range (-40°C to +125°C) makes it suitable for under-hood automotive and outdoor industrial deployments.
Рекомендуется
Isolated I2C Bus (Bidirectional Channel Use)
Although the SI8645BA-B-IUR is a unidirectional-only isolator, two channels can be paired to isolate a bidirectional I2C bus (SCL + SDA), with pull-ups placed on each side of the barrier. The 150 Mbps rate vastly exceeds I2C's 400 kHz / 1 MHz / 3.4 MHz speeds, leaving timing margin for slow rise-time filtering. The fail-safe default-high keeps both SDA and SCL high when the controller side powers down, avoiding false START conditions. Use a Skyworks Si8602 or Si8641BD-B-ISR (1+1 channel bidirectional variant) if bidirectional isolation in a single IC is required.
Рекомендуется
Battery-Management System (BMS) Isolation
In multi-cell battery management systems, the SI8645BA-B-IUR isolates the high-voltage cell-monitoring stack from the low-voltage MCU host, while its 150 Mbps headroom easily handles the SPI traffic to multi-megahertz AFEs such as the LTC6811. The 35 kV/µs CMTI handles the dV/dt transitions of large MOSFET half-bridges in the battery pack. The four-channel count supports SPI CLK, MOSI, MISO, and a chip-select or alert line in a single IC, reducing the BOM and PCB area. Industrial temperature grade suits under-hood automotive and stationary-storage environments.
Рекомендуется
Isolated Digital I/O for PLCs
The SI8645BA-B-IUR is well-suited to isolated digital-input modules in programmable-logic controllers (PLCs), where each channel carries a 24 V field input back to the 5 V or 3.3 V logic domain. The 1 kVrms isolation barrier protects the PLC backplane from field-side transients, while the 35 kV/µs CMTI rejects the noise induced by nearby relay and contactor coils. Four channels per IC give a compact solution for 4-channel DI cards; stacking multiple SI8645BA-B-IURs scales to 8, 16, or 32-channel modules without layout changes. The wide supply range accepts both 24 V-derived and 5 V-rail designs.
Рекомендуется
Сводка рекомендуемых товаров
Справочные инженерные данные для SI8645BA-B-IUR — сравнение, рекомендации по проектированию и информация о соответствии.
Руководство по выбору
Сравнение с аналогами
| Параметр | Этот товар | SI8645BA-B-IU | SI8645BB-B-IUR | SI8642BB-B-IU | SI8641BD-B-ISR | SI8640BD-B-IS |
|---|---|---|---|---|---|---|
| Package | QSOP-16 (3.90mm) | QSOP-16 (3.90mm) - same | QSOP-16 (3.90mm) - same | QSOP-16 (3.90mm) - same | QSOP-16 (3.90mm) - same | QSOP-16 (3.90mm) - same |
| Brand | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions |
| Channels | 4 (unidirectional) | 4 (unidirectional) | 4 (3 fwd / 1 rev) | 2 (unidirectional) | 2 (1 fwd / 1 rev) | 4 (unidirectional) |
| Isolation Voltage | 1 kVrms | 1 kVrms | 1 kVrms | 1 kVrms | 1 kVrms | 1 kVrms |
| Data Rate | 150 Mbps | 150 Mbps | 150 Mbps | 150 Mbps | 150 Mbps | 150 Mbps |
| CMTI | 35 kV/µs | 35 kV/µs | 35 kV/µs | 35 kV/µs | 35 kV/µs | 35 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 | 2.5 V to 5.5 V | 2.5 V to 5.5 V |
| Fail-Safe Default | High | High | High | High | High | High |
| Operating Temperature | -40°C to +125°C | -40°C to +125°C | -40°C to +125°C | -40°C to +125°C | -40°C to +125°C | -40°C to +125°C |
| Packaging | Tape & Reel (2500) | Tube | Tape & Reel | Tube | Tape & Reel | Tube |
Ключевые отличия
- Higher CMTI than typical TI ISO77xx family (против TI ISO7741)
- Wider supply-voltage range than ADUM1402 (против Analog Devices ADUM1402)
- Same Skyworks family vs cross-brand alternatives (против TI ISO7741 / ADI ADUM1402)
- Higher data rate than most 1 kVrms competitors (против TI ISO7741)
Заметки по проектированию
Route the isolated ground returns (GND1 and GND2) directly under the IC body with a continuous pour, and place 0.1 µF + 10 µF bypass capacitors on each VDD pin within 2 mm. The QSOP-16 package requires that the data traces not cross the isolation barrier (pin 1-8 to pin 9-16) on any layer, since coupling across the barrier reduces effective CMTI.
Do not leave unused input pins floating. Tie them to VDD1 or GND1 to prevent shoot-through current in the input buffer. The fail-safe default-high output pulls the output high when the input side loses power - design the downstream logic so that a high level on the output is the safe state, not an enable signal.
At data rates above 100 Mbps, match the input trace lengths (INA, INB, INC, IND) to within 2 mm to avoid channel-to-channel skew. The SI8645BA-B-IUR's typical propagation delay is approximately 10 ns with sub-ns skew, so PCB skew should be a small fraction of this budget. Use 50 ohm controlled-impedance traces if extending beyond the QSOP, and add a 22 ohm series resistor at the driver output to dampen reflections.
Estimated: at full 150 Mbps and 5.0 V on both supplies, each channel consumes approximately 5 mW, totaling ~25 mW for the part. With a theta_JA of approximately 80 C/W for QSOP-16, the junction temperature rise above ambient is roughly 2°C - well within thermal limits. No heatsink or thermal vias are required.
Информация о соответствии
RoHS compliant per Skyworks product page. Not AEC-Q100 qualified - this is a general-purpose industrial part. The Si864x family is now serviced by Skyworks Solutions following Silicon Labs' 2021 sale of its isolation portfolio.
