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Home > Products > Isolators > Digital Isolators

Skyworks Solutions Inc. SI8640AB-AS

Name: SI8640AB-AS
Brand: Skyworks Solutions Inc.
SKU: SI8640AB-AS
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SI8640AB-AS

Manufacturer:: Skyworks Solutions Inc.

Category:: Digital Isolators

Package:: 16-SOIC (0.295", 7.50mm Width)

Datasheet:: SI8640AB-AS.pdf

Description:: AUTOMOTIVE 2.5 KV 4-CHANNEL DIGI

Quantity:: RFQ Add To RFQ list

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Product details

Overview

SI8640AB-AS from Skyworks is a quad-channel, unidirectional digital isolator with 4 input channels on VDD1 side and 0 on VDD2 side, rated for 2.5 kV_RMS isolation, 150 Mbps data rate, and –40 to 125 °C operation. It features Schmitt-trigger inputs, tri-state outputs with single enable control (EN), and selectable fail-safe low-default output state - used in isolated ADC interfaces, motor control gate drivers, and industrial PLC I/O modules.

For engineers reviewing the SI8640AB-AS datasheet, SI8640AB-AS pinout, SI8640AB-AS application, or SI8640AB-AS equivalent, key selection criteria include its 2.5 kV reinforced insulation rating, SOIC-16 wide-body package with 8 mm creepage, automotive-grade AEC-Q100 qualification, and ultra-low 1.6 mA/channel supply current at 1 Mbps (5 V).

Technical Context

The SI8640AB-AS implements RF-based on/off keying across a silicon-dielectric isolation barrier, eliminating startup initialization and enabling robust noise immunity without optical degradation. Its architecture supports independent undervoltage lockout (UVLO) on both sides, with VDDUV+ = 2.24 V (typ) and hysteresis of 70 mV (typ), ensuring clean power-up behavior in noisy industrial environments.

All four channels are unidirectional from Side A (VDD1) to Side B (VDD2); EN is located on Side B and controls all four outputs simultaneously. The device uses internal pull-downs on inputs/outputs for its default-low fail-safe mode, delivering deterministic logic-low outputs during input-side power loss while maintaining output-side functionality.

Key Specifications

Parameter	Value and Actual Design Meaning
Isolation Rating	2.5 kV_RMS reinforced insulation per UL 1577 and VDE 0884-10 (basic), certified for industrial and automotive use.
Max Data Rate	150 Mbps - supports high-speed serial interfaces like SPI, RS-485 transceiver control, and isolated CAN FD signaling paths.
Propagation Delay	8 ns (typ) - enables tight timing budgets in real-time motor control feedback loops and isolated ADC sampling clocks.
Channel-Channel Skew	0.5 ns (typ) - ensures synchronous edge alignment across all four isolated signals in multi-channel sensor acquisition systems.
Supply Current @ 1 Mbps	1.6 mA per channel at 5 V - reduces thermal load and extends battery life in isolated power monitoring circuits.
Common-Mode Transient Immunity	60 kV/µs (typ) - maintains signal integrity in high-dV/dt environments such as IGBT gate drive circuits and inverters.
Fail-Safe Default	Logic-low output during VDD1 loss - prevents unintended activation of downstream MOSFETs or relays in fault conditions.

Pinout & Package

SI8640AB-AS is housed in a RoHS-compliant SOIC-16 wide-body package (–AS suffix), measuring 10.3 mm × 10.3 mm × 2.3 mm with 8 mm creepage distance and reinforced insulation capability.

Pin/Terminal	Circuit Role	Design Meaning
VDD1	Input-side power supply	2.5–5.5 V supply for Side A logic and RF transmitter; bypassed with 0.1 µF capacitor near pin.
GND1	Input-side ground reference	Return path for VDD1; must be separated from GND2 by ≥8 mm creepage for safety compliance.
INA1–INA4	Unidirectional input channels	CMOS/Schmitt-trigger inputs accepting 2.0–5.5 V logic; no external bias required.
VDD2	Output-side power supply	2.5–5.5 V supply for Side B receiver and output drivers; independent of VDD1 for galvanic isolation.
GND2	Output-side ground reference	Return path for VDD2; forms isolation barrier boundary with GND1.
EN	Enable control input	Active-high signal on Side B; drives all four outputs into high-impedance when low - enables shared bus arbitration.
OUTB1–OUTB4	Isolated output channels	50 Ω nominal output impedance; compatible with 50 Ω PCB traces for >50 Mbps operation.

Key Features

Feature	Design Value
RF-based isolation barrier	Eliminates LED aging and temperature drift issues of optocouplers; guarantees 60-year lifetime at rated working voltage.
Tri-state output control	Single EN pin disables all four outputs simultaneously into high-impedance, enabling multi-drop bus sharing without external logic.
Selectable fail-safe mode	Factory-configured low-default output ensures safe deactivation of power stages during input-side brownout or disconnect.
AEC-Q100 Grade 1 qualification	Validated for automotive applications including battery management systems and on-board chargers operating from –40 to 125 °C.
High CMTI performance	60 kV/µs common-mode transient immunity prevents false triggering in high-noise motor drive and inverter applications.

Applications

Industrial PLC I/O Isolation	Isolated ADC Interface
Use Scenario: Digital input modules in programmable logic controllers require galvanic separation between field sensors and backplane logic. IC Role / Device Role / Timing Role: SI8640AB-AS isolates four 24 V DC sensor inputs to 3.3 V microcontroller GPIOs with precise timing and no latency accumulation. Use Value: 0.5 ns channel-channel skew ensures synchronized sampling of multi-sensor arrays; 2.5 kV rating meets IEC 61000-4-5 surge immunity requirements.	Use Scenario: High-resolution analog-to-digital converters in energy metering systems need isolated digital control and data lines. IC Role / Device Role / Timing Role: SI8640AB-AS carries SPI clock, CS, and data lines across isolation barrier while preserving setup/hold timing margins. Use Value: 8 ns propagation delay and 5 ns minimum pulse width support 10+ MSPS sampling rates; Schmitt-trigger inputs reject EMI-induced glitches.
Motor Control Gate Driver Isolation	Battery Management System Communication
Use Scenario: Isolating PWM signals from MCU to half-bridge gate drivers in servo inverters to prevent ground loop damage. IC Role / Device Role / Timing Role: SI8640AB-AS delivers four matched, low-skew PWM channels to isolated gate driver ICs with fail-safe low default. Use Value: Fail-safe low prevents shoot-through during MCU reset; 150 Mbps rating accommodates advanced modulation schemes like SVM and SVPWM.	Use Scenario: Communication between cell monitor ICs and main BMS controller across isolation barrier in EV battery packs. IC Role / Device Role / Timing Role: SI8640AB-AS isolates UART or custom serial links between isolated slave nodes and master controller. Use Value: AEC-Q100 qualification ensures reliability under automotive thermal cycling; 60 kV/µs CMTI rejects transients from adjacent high-power switching cells.

Industrial PLC I/O Isolation

Isolated ADC Interface

Use Scenario: Digital input modules in programmable logic controllers require galvanic separation between field sensors and backplane logic.

IC Role / Device Role / Timing Role: SI8640AB-AS isolates four 24 V DC sensor inputs to 3.3 V microcontroller GPIOs with precise timing and no latency accumulation.

Use Value: 0.5 ns channel-channel skew ensures synchronized sampling of multi-sensor arrays; 2.5 kV rating meets IEC 61000-4-5 surge immunity requirements.

Use Scenario: High-resolution analog-to-digital converters in energy metering systems need isolated digital control and data lines.

IC Role / Device Role / Timing Role: SI8640AB-AS carries SPI clock, CS, and data lines across isolation barrier while preserving setup/hold timing margins.

Use Value: 8 ns propagation delay and 5 ns minimum pulse width support 10+ MSPS sampling rates; Schmitt-trigger inputs reject EMI-induced glitches.

Motor Control Gate Driver Isolation

Battery Management System Communication

Use Scenario: Isolating PWM signals from MCU to half-bridge gate drivers in servo inverters to prevent ground loop damage.

IC Role / Device Role / Timing Role: SI8640AB-AS delivers four matched, low-skew PWM channels to isolated gate driver ICs with fail-safe low default.

Use Value: Fail-safe low prevents shoot-through during MCU reset; 150 Mbps rating accommodates advanced modulation schemes like SVM and SVPWM.

Use Scenario: Communication between cell monitor ICs and main BMS controller across isolation barrier in EV battery packs.

IC Role / Device Role / Timing Role: SI8640AB-AS isolates UART or custom serial links between isolated slave nodes and master controller.

Use Value: AEC-Q100 qualification ensures reliability under automotive thermal cycling; 60 kV/µs CMTI rejects transients from adjacent high-power switching cells.

Equivalent & Alternatives

The following parts are listed as comparable options for similar digital isolator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ADUM140D0BRIZ	4-channel, 150 Mbps, 3.75 kV_RMS, SOIC-16 narrow body, no EN pin, default-high only	Lacks enable control and fail-safe low option; narrower creepage (4.1 mm) limits high-voltage system use	Choose ADUM140D0BRIZ only if board space is constrained and fail-safe low is not required.
ISO6740QDWR	4-channel, 50 Mbps, 5 kV_RMS, SOIC-16 wide body, AEC-Q100 qualified, no EN pin	Lower data rate restricts use in high-speed SPI or fast UART; lacks tri-state capability for bus sharing	Prefer ISO6740QDWR where higher isolation (5 kV) is mandatory but speed ≤50 Mbps suffices.

Compared with ADUM140D0BRIZ and ISO6740QDWR, SI8640AB-AS uniquely combines AEC-Q100 qualification, 150 Mbps speed, integrated EN control, and factory-set fail-safe low - making it optimal for automotive and industrial systems requiring both safety and real-time responsiveness.

Availability

SI8640AB-AS is available at Aetrix Electronics and suitable for industrial automation systems, battery management systems, and motor control applications requiring stable component supply, long-term lifecycle support, and automotive-grade reliability.

Supply support for SI8640AB-AS 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 Si864x family was designed specifically for high-reliability industrial and automotive isolation needs - emphasizing low power, precise timing, reinforced safety certification, and extended temperature operation without optical compromises.

FAQ

What is the isolation rating and safety certification status of SI8640AB-AS?

SI8640AB-AS is rated for 2.5 kV_RMS reinforced isolation and certified to UL 1577 (1 min), CSA Component Notice 5A, VDE 0884-10 (basic insulation), and IEC 62368-1. It meets AEC-Q100 Grade 1 requirements for automotive use and supports reinforced insulation per IEC 60950-1. Certification documentation is available upon request from Skyworks.

Does SI8640AB-AS support bidirectional communication?

No, SI8640AB-AS is a unidirectional isolator with all four channels configured from VDD1 (input side) to VDD2 (output side). It does not support reverse data flow. For bidirectional applications, consider SI8641AB-AS (3:1 channel split) or SI8642AB-AS (2:2 split), both in the same Si864x family.

How does the EN pin function on SI8640AB-AS?

The EN pin on SI8640AB-AS is an active-high enable input located on the VDD2 (output) side. When EN = high, all four outputs (OUTB1–OUTB4) follow their respective inputs (INA1–INA4). When EN = low, all outputs enter high-impedance state - enabling shared bus architectures without external tri-state logic.

What is the default output state during input-side power loss for SI8640AB-AS?

SI8640AB-AS is configured with a factory-selectable fail-safe mode: "low" default. When VDD1 is unpowered but VDD2 remains active, all four outputs (OUTB1–OUTB4) drive logic-low - preventing unintended activation of downstream power switches or actuators in fault conditions.

Can SI8640AB-AS operate with mixed supply voltages on VDD1 and VDD2?

Yes, SI8640AB-AS supports independent 2.5–5.5 V supplies on VDD1 and VDD2. This allows level-shifting between 3.3 V microcontrollers and 5 V peripheral logic, or interfacing with different domain voltages in isolated power domains - with full timing specifications guaranteed across the entire voltage range.

SI8640AB-AS Specifications

Product attributes: Attribute value

Manufacturer:: Skyworks Solutions Inc.

Series:: Si864x

Package/Case:: 16-SOIC (0.295", 7.50mm Width)

Packaging:: Tube

Product Status:: Active

Technology:: Capacitive Coupling

Type:: General Purpose

Isolated Power:: Yes

Number of Channels:: 4

Inputs - Side 1/Side 2:: -

Channel Type:: Unidirectional

Voltage - Isolation:: -

Common Mode Transient Immunity (Min):: 35kV/µs

Data Rate:: 150Mbps

Propagation Delay tpLH / tpHL (Max):: 13ns, 13ns

Pulse Width Distortion (Max):: 4.5ns

Rise / Fall Time (Typ):: 2.5ns, 2.5ns

Voltage - Supply:: 2.375V ~ 5.5V

Grade:: Automotive

Qualification:: AEC-Q100

Operating Temperature:: -40°C ~ 125°C

Mounting Type:: Surface Mount

Supplier Device Package:: 16-SOIC

SI8640AB-AS FAQ

1.How can I place an order for SI8640AB-AS through Aetrix?

Please submit a Request for Quotation (RFQ) for SI8640AB-AS 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 SI8640AB-AS reliable?

The price and inventory of SI8640AB-AS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI8640AB-AS is usually 5 days.

3.What payment methods are accepted for SI8640AB-AS?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI8640AB-AS transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SI8640AB-AS?

SI8640AB-AS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SI8640AB-AS 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 SI8640AB-AS?

For technical support, including SI8640AB-AS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI8640AB-AS requirements.

6.How does Aetrix verify that SI8640AB-AS is sourced from the original manufacturer or authorized distributors?

All SI8640AB-AS 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 SI8640AB-AS meets industry standards.

7.What is the process for return or replacement of SI8640AB-AS?

All SI8640AB-AS units undergo pre-shipment inspection (PSI). If there is an issue with SI8640AB-AS, 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 SI8640AB-AS part is unused and in its original packaging.

Return procedure for SI8640AB-AS:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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