Home > News > News Room > STMicroelectronics’ RS-485 transceivers combine robust signaling with superior speed for cutting-edge applications in industrial automation, smart buildings, and robotics

News

STMicroelectronics’ RS-485 transceivers combine robust signaling with superior speed for cutting-edge applications in industrial automation, smart buildings, and robotics

10/04/2024
article image

STMicroelectronics has introduced the ST4E1240 RS-485 transceiver with 40Mbit/s speed, PROFIBUS-compatible output, and transient and hot-swap protection.

The ST4E1240 is the first in a new family of transceivers from ST featured to deliver robust and reliable RS-485 signaling for modern, performance-hungry industrial applications. The new transceivers support data speeds far above the original RS-485 standards and allow multipoint connections over extended cable runs with more than 64 transceivers on the bus. Typical uses are in programmable logic controllers (PLCs), robots, telecom infrastructures, smart-building controls, servo drives, optical networking devices, grid infrastructure, data-acquisition systems including smart meters, and backplane buses.

The protection built into the ST4E1240 meets IEC 61000-4-2 up to +/-12kV contact discharge, allowing the devices to be used without external ESD protection. There is also class-A fast-transient protection up to +/- 4kV, meeting IEC 61000-4-4, ensuring data integrity and bus stability. Hot-swap circuitry prevents unwanted states on the bus during device switch-on or plug-in and is capable of discharging up to 100pF parasitic capacitance. Furthermore, the transceiver integrates failsafe protection that drives the output high to avoid an indeterminate state upon detecting an open, shorted, or idle bus. Other features include 250mA short-circuit protection and thermal shutdown.

The ST4E1240 fulfils all TIA/EIA-485 (RS-485) standards and ensures the output differential voltage exceeds 2.1V, at 5V supply, for compatibility with the popular PROFIBUS field bus standard. There is also a shutdown mode, controlled with external enable pins, that reduces the quiescent current below 3.5µA for use in energy-conscious applications.

The ST4E1240 RS-485 transceiver is part of ST’s 10-year longevity program that ensures long-term product support. The devices are in production now and available in the SO-8 4.9mm x 3.91mm package, from $0.81 for orders of 1000 pieces.

High-speed 3.3 V / 5 V RS485 transceiver with ± 12 kV IEC 61000-4-2 contact ESD protection

The ST4E1216 and ST4E1240 are low-power differential line transceivers for data transmission standard RS485 applications in half-duplex mode, compatible with either 3.3 V or 5 V rail power supplies, fully operating from 3 V to 5.5 V.

The ST4E1216 and the ST4E1240 operate respectively up to 16 Mbps and 40 Mbps. They are ideal for multipoint applications over extended cable runs. They are robust to ESD transients. In particular, the bus pins support ±12 kV IEC 61000-4-2 contact discharge. They also feature robust hot-swap capability during switching on and off, or during hot insertion.

The ST4E1216 and ST4E1240 are available in the standard SO-8 package and operate respectively with a -40 °C to 125 °C and -40 °C to 85 °C temperature range.

  • All features

    • Meets or exceeds TIA/EIA-485A standard requirements
    • 3 V to 5.5 V supply voltage
    • Differential output voltage (VOD) exceeds 2.1 V at 5 V supply for PROFIBUS compatibility
    • High speed: up to 40 Mbps data rate
    • More than 64 transceivers on the bus (up to 100 nodes)
    • Integrated protections
      • Fail-safe receiver (bus open, idle, and shorted)
      • Thermal shutdown protection
      • Hot-swap capability (with parasitic capacitance up to 100 pF)
      • Bus I/O ESD protection±12 kV IEC61000-4-2 contact discharge≥ ±8 kV HBM ESD±4 kV IEC61000-4-4 class-A fast transient burst (EFT)
    • Low quiescent current in shutdown mode
    • Available in industry standard SO-8
SPECIALIST NEWS
  • 08/09/2023

    RSA Design: LORA

  • 22/08/2023

    FG23 Wireless Sub-GHz SoC

    Silicon Labs’ wireless sub-GHz SoC enables Amazon Sidewalk, mioty, Wireless M-Bus, and Z-Wave Silicon Labs’ FG23 is the industry’s first wireless sub-GHz SoC with an Arm® Cortex®-M33, a dedicated security core and Arm PSA3 certification. The device improves on the leading RF performance of Series 1 and now enables 10+ year coin cell battery operation. The […]

  • 23/08/2023

    STEVAL-IDS001V3, Demonstration Board based on the SPIRIT1 Low data-rate, short-range USB dongle transceiver in 433-MHz band

    Description STEVAL-IDS001V3, Demonstration Board based on the SPIRIT1 Low data-rate, short-range USB dongle transceiver in 433-MHz band. The STEVAL-IDS001V4 demonstration board is based on the SPIRIT1, which is a sub-GHz low power, low data-rate transceiver suitable for ISM bands and Wireless M-BUS. The board is equipped with an STM32L low power microcontroller to control the […]

  • 22/08/2023

    Silicon Labs xG28 Now Available; Helping Customers Like Chamberlain Group and Honeywell with Long-Range Applications at the Edge

    In June, we announced our dual-band FG28 SoC, designed for long-range networks and protocols like Amazon Sidewalk, Wi-SUN, and other proprietary protocols. Today, we’re excited to share that the FG28 is now generally available through Silicon Labs and our distribution partners. Learn more about the dual-band FG28 SoC here. We’re also extending our xG28 family of SoCs with the ZG28, […]

  • 31/07/2023

    FG25 Sub-GHz SoC Now Available for Smart Cities and Long-Range Deployments

    During our Works With 2022 Developer Conference, we announced our new flagship sub-Ghz SoC, the FG25, and today we are pleased to announce that it is generally available through Silicon Labs and our distribution partners. The FG25 is the ideal SoC (system on chip) for long-range, low-power transmissions, capable of broadcasting up to 1.6km with minimal data […]

  • 31/07/2023

    Smart City Living Lab Series: Making Hyderabad, India a Smarter City with Wi-SUN

    Specifically designed for smart cities, Wireless Smart Ubiquitous Network (Wi-SUN) is a protocol for low-power Internet of Things (IoT) mesh networks. With its scalability, security, interoperability, and support for a wide range of existing and emerging apps, Wi-SUN is an excellent foundation for sustainable city operations and, ultimately, better quality of life for residents. Cities around […]

  • 27/07/2023

    Smart City Living Lab Wi-SUN FAN 1.1 Mesh Deployment – Phase 2

    As part of the ongoing blog series on the Smart City Living Lab at IIIT Hyderabad, this second post will delve deeper into the details of the inner workings of the state-of-the-art Wi-SUN-enabled Smart City Living Lab. The lab, which stands as a testament to the immense potential of IoT in daily life, mirrors a Smart City on […]