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Wireless Communication LSIs Compatible
with the Wireless M-Bus Standard for Smart Meters in Europe    ML7406

2013 News Release

May 23, 2013

Wireless Communication LSIs Compatible with the Wireless M-Bus Standard for Smart Meters in Europe    ML7406

Long-term operation even with compact low-capacity batteries

LAPIS Semiconductor Co., Ltd., a ROHM Group Company, has recently developed a wireless communication LSI compatible with 868MHz Wireless M-Bus *1, the European smart meter communication standard. Signal processing functions required for each mode are built in, reducing microcontroller load by about 20% and contributing to lower power consumption of the entire system along with longer operating time and reduced maintenance for battery-operated smart meters.

In recent years, efforts to establish smart meters have begun in several countries. The 868MHz band Wireless M-Bus transmission method, which is likely to become popular in Germany and the surrounding countries and ultimately adopted as the mainstream communication method in Europe, has 3 modes. Signals must be discriminated differently for each mode based on the operating function. Conventionally, packet processing for discriminating modes and messages was commonly performed by software on the microcontroller side, placing an extremely high load on the microcontroller, resulting in higher power consumption.

The ML7406, which supports the frequency band from 750MHz to 960MHz, is compatible with the ARIB STD-T108*2 standard in Japan as well as the global standard IEEE802.15.4g, making it suitable for a wide range of fields throughout the world, including smart meters and energy management systems (EMS).

LAPIS Semiconductor, in collaboration with Steinbeis, a major vendor and key member of the group responsible for establishing the OMS (Open Metering System)*3protocol, developed specifications for hardware-based packet processing and integrated a Wireless M-Bus packet handler into the LSI. The packet handler is designed to perform hardware-based processing of a variety of functions, such as simultaneous standby for interoperability between C and T Modes, automatic discrimination of Format A and B messages in C Mode, and address filtering that automatically distinguishes whether packets are intended for this or other devices. As a result, microcontroller operating rate is reduced by about 20% compared with conventional software-based systems, significantly cutting device power consumption.

LAPIS Semiconductor can supply sample software and C source code that include all of the T, C, and S Mode functions compatible with EN113757-4:2011 in the Wireless M-Bus protocol stack. In addition, an industry-standard OMS-compatible protocol stack that can be used without modification in OMS-based meters, along with Wireless M-Bus protocol analysis software, can be licensed from Steinbeis.

The 868MHz ML7406 joins the ML7344E, which is compatible with the 169MHz (N Mode) and 433MHz (F Mode) bands, completing LAPIS Semiconductor’s lineup for the Wireless M-Bus standard and ensuring compatibility with smart meter applications throughout Europe.


  • *1 : Wireless M-Bus (Meter-Bus)
    • A European standard for the remote reading of meters (‘Communication Systems for Meters and Remote Reading Part 4: Wireless Meter’). It defines operation at 868MHz for T, C, and S Modes, 433MHz for F Mode, and 169MHz for N Mode.
      • T Mode (Frequent Transmit Mode)
        A mode for systems that require frequent data transfer such as electric meters
      • C Mode (Compact Mode)
        Optimized for battery-operated systems such gas and water meters
      • S Mode (Stationary mode)
        Developed for systems that transfer data infrequently
  • *2 : ARIB STD-T108
    • A wireless equipment standard for telemetry, telecontrol, and data transmission using the 920MHz band in Japan
  • *3 : OMS (Open Metering System)
    • A protocol standard for meter systems established by the German meter industry that run on Wireless M-Bus


  • Sample Shipment
    • Now (Samples), September 2013 (OEM Quantities)

Key Features

  • Wireless M-Bus packet handler
    • Supports T, C, and S Modes
    • Equipped with an automatic discrimination function for Formats A and B in C Mode
    • Integrates an automatic discrimination function for C and T Modes
    • Automatically executes operation and insertion of CRC data corresponding to each mode
    • Can connect to conventional T Mode supporting a data rate deviation of 12%
  • General-purpose packet handler
    • Functions as an IEEE 802.15.4g*4 packet handler based on register settings
  • Automatic Wakeup/Sleep, and high-speed carrier checking functions
    • By controlling the built-in timer using internal 32kHz RC oscillation or external clock input, the LSI can periodically, without any instructions from the microcontroller, wake up from Sleep Mode, run in Receive or Send Mode, and then return to Sleep Mode. Combining this operation with a high-speed carrier checking function allows the microcontroller to regularly detect the presence of radio waves in the shortest time possible and, if no radio waves exist, go back to sleep.
  • Multiple sleep modes
    • The ML7406 features five sleep modes (including Deep Sleep mode). The most suitable sleep mode can be selected based on system configuration and needs.


  • *4 : IEEE 802.15.4g
    • A wireless standard for smart utility networks established by the US standards organization IEEE


  • Smart meters, HEMS / BEMS / FEMS*5 systems in Japan
  • Smart meters (Wireless M-Bus T, C, and S Mode devices) in Europe


  • *5 : HEMS / BEMS / FEMS
    • Types of Energy Management Systems (EMS). H stands for Home, B for Building, and F for Factory.

Sales Plan

  • Part No.
    • ML7406
  • Packaging
    • Tape and reel (1000pcs)
  • Sample Shipment
    • April 2013
  • Sample Price
    • 500 yen (tax not included)
  • Evaluation Board (Single Unit)
    • April 2013 (delivered approx. 2 months after ordering)
  • Mass Production
    • From September 2013 (planned)


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