Product News: Electrical Equipment & Systems

Bidirectional I2C Isolators extend industrial isolation lifetime.

Press Release Summary:

December 14, 2012 - Supplied in 8-pin SOIC packages, ISO1540 and ISO1541 can replace typical implementation of 16 or more discrete devices to isolate I²C signal. Transient immunity of ±50 kV/µsec typ and switching time with max propagation delay of 62 nsec extend isolation. While ISO1540 provides 2 isolated bidirectional channels for clock and data lines for use in applications with multiple masters, ISO1541 includes bidirectional data and unidirectional clock channel for single-master applications.

Texas Instruments, Inc., Semiconductors - Dallas, TX

Original Press Release

Lowest-Power, Bidirectional I2C Isolators Extend Industrial Isolation Lifetime

Press release date: December 12, 2012

Two new TI isolators improve transient immunity and switching performance

DALLAS -- Texas Instruments Incorporated (TI) (NASDAQ: TXN) today introduced a bidirectional isolator family compatible with I2C interfaces that consumes as much as 38-percent lower power than competitive devices. Each of the new integrated circuits (ICs) can replace a typical implementation of 16 or more discrete devices to isolate the I2C signal in industrial applications. In addition, the ISO1540 and ISO1541 offer better transient immunity and faster switching times than optocouplers. This performance provides longer-lasting isolation in a variety of applications, such as power supplies, networking, telecommunications, Power over Ethernet (PoE) and battery management systems. For more information and to order samples, visit

The ISO1540 and ISO1541 employ a unique capacitive isolation technology with a silicon dioxide barrier (SiO2) to separate logic input and output buffers. This approach extends the lifetime of the isolators by more than three times compared to optocouplers or magnetic isolators. The ISO1540 provides two isolated bidirectional channels for clock and data lines for use in applications that have multiple masters. The ISO1541 includes a bidirectional data and a unidirectional clock channel for use in single-master applications. The I2C isolator family joins TI's portfolio of long-lifetime digital isolation products, including devices with isolated CAN or RS-485 interface; isolated amplifiers; or other isolated functions for industrial applications.

Key features and benefits of the ISO1540 and ISO1541

--  Lowest power: With maximum current of less than 8.5 mA at 5 V, the ISO1540 and ISO1541 reduce power consumption by up to 38 percent compared to competitive ICs, reducing heat generation in industrial applications.
--  Fastest switching time: Maximum propagation delay of 62 nanoseconds is 52-percent better than competitive ICs, enabling faster data transfer.
--  Higher reliability: ± 50-kV/us typical transient immunity provides better reliability in harsh environments.
--  Prevents internal logic latch: Isolated bidirectional communications is accomplished within these devices by employing an offset configuration that prevents device latch-up and ensures reliable operation.

Complete isolated system power

To provide secondary power supply to the ISO1540 and ISO1541, the SN6501 transformer driver can be used in conjunction with a transformer, rectifier and a regulator, such as TI's 5V TPS70950 or 3.3V TPS70933. The result is a small, low-cost, high-efficiency, low electro-magnetic interference (EMI) solution for generating isolated power to the system. The SN6501 evaluation module can be used to evaluate the performance of these devices in an application where only a single power supply is available to power both sides of the isolation barrier.

Tools and support

The ISO1540EVM is available to evaluate device parameters for both the ISO1540 and ISO1541, while acting as a guide for board layout. It can be ordered today for US$49.

Support is available on the Industrial Interface Forum in the TI E2E(TM) Community, where engineers designing with the ISO1540 and ISO1541 can ask questions and get answers from TI experts.

Availability, packaging and pricing

The ISO1540 and ISO1541 are available in industry-standard, 8-pin SOIC packages. Suggested retail pricing in 1,000-unit quantities is US$2.00 and US$1.80, respectively.

Learn more about TI's isolation portfolio by visiting the links below:

--  Order ISO1540 samples:
--  Order ISO1541 samples:
--  Order ISO1540 evaluation modules:
--  Order the SN6501 evaluation module:
--  Follow the latest signal chain insights on our blog:
--  Download a news release graphic at:

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