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TI Introduces Industry's First On-Chip Capacitive Digital Isolators

Increased Speed and Magnetic Immunity with High Reliability Improve System Performance and Reduce Cost

Jan 23, 2006

DALLAS (Jan. 23, 2006) - Texas Instruments Incorporated (TI) [NYSE: TXN] today introduced a family of high-performance digital isolators, featuring on-chip capacitors to enable faster data transmission with higher signal integrity. These capacitive isolators lead the industry with the fastest data rates combined with high reliability, provide six orders of magnitude higher magnetic immunity than existing inductive devices, and use 60 percent less power than high-performance optocouplers. (See www.ti.com/iso721-pr.) The new isolators improve system performance and reduce cost in high-voltage, noisy applications such as factory automation, process control and data acquisition systems.

"Using the intrinsic capacitor properties, TI's technology behind the ISO721 and ISO721M delivers great immunity from magnetic noise sources," said Art George, vice president of TI's high performance linear business. "It enables the perfect combination of high-speed data transmission with industrial-grade requirements for reliability to match the performance and long lifetime needs of industrial isolation applications."
The ISO721 and ISO721M provide high-performance data transmission and circuit protection with isolation of up to 560 Volts of operating voltage or 4000-V peak overvoltage transient. The ISO721M is suited for applications requiring fast digital data to be transmitted with low incidence of system noise. The ISO721 is more flexible and robust for transmitting data in noisy environments. The devices meet the standards for isolators set by Underwriters Laboratory (UL 1577), International Electrotechnical Commission (IEC 60747-5-2) and Canadian Standards Association (CSA Component Acceptance Notice 5A).
By using on-chip, high-voltage capacitors, the TI isolators transmit data up to three times faster while using less power than commonly-used high-performance optocouplers. In addition, TI's capacitive technology offers the advantage of immunity from external magnetic fields that frequently occur in the industrial environment and can distort signal integrity. These devices also offer high immunity against data corruption due to fast voltage transients, providing a minimum protection level of 25 kV/microsecond.
TI's isolators use a semiconductor-grade silicon oxide dielectric. This stable, high-performance insulator provides proven reliability and long operational life. These are critical requirements in industrial applications where voltage surges can otherwise degrade device lifetime. At typical operating voltage, each device's life expectancy exceeds 25 years.

ISO721 Additional Key Features

  • TTL inputs with noise filter: 100 Mbps 
  • Low propagation delay: 17 ns (typical) 
  • Low jitter: 2 ns (typical) 
  • Supports 3-V or 5-V


ISO721M Additional Key Features 

  • CMOS inputs without noise filter: 150 Mbps 
  • Low propagation delay: 10 ns (typical) 
  • Low jitter: 1 ns (typical) 
  • Supports 3-V or 5-V





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Available Today

The ISO721 and ISO721M devices are now available from TI and authorized distributors in an eight-pin small-outline integrated circuit (SOIC) package. The price is $1.65 in 1,000-unit quantities. An evaluation module is available.