Smart meter wireless chip has worldwide RF compatibility

Smart meter wireless chip has worldwide RF compatibility

New Products |
By Graham Prophet

This sub-GHz wireless LSI is aimed at smart meters and wireless networks around the world. The ML7345 covers a wide range of sub-GHz frequencies (160 MHz to 960 MHz), providing universal compatibility. Improving high-frequency amplifiers makes it possible to achieve class-leading wireless performance and environmental stability (more than 3x the transmission power temperature resistance), simplifying wireless network configuration (i.e. of smart meters) while improving reliability (e.g. reducing the number of relays). In addition, a high-speed radio wave check function that performs receiver startup in a short period of time, combined with significantly reduced sleep current during standby (which accounts for the majority of communication time), decreases average current by 48% compared with conventional products, leading to lower system power consumption and longer battery life.


Broad compatibility (160MHz to 960MHz) ensures compliance with the ARIB STD-T108 standard in Japan as well as IEEE802.15.4g, enabling global support for applications such as smart meters and energy management systems (EMS).

The ML7345 is compliant with the latest (2013) version of the Wireless M-bus standard. Improvements made over the conventional Wireless M-bus packet handler ensures support for the newest extended packet specifications.

High output (100 mW) is optimized for the Chinese market in a variant coded ML7345C. Along with 100 mW antenna output, the ML7345C delivers programmable receiver bandwidth settings that support a wide range of specifications, from electricity, gas, water, and thermal meters to crime and disaster prevention systems.

In addition to improving high-frequency amplifier performance, a transmission power variation of less than ±1dB is ensured across the entire operating temperature range, providing more than 3x the stability of conventional products. This allows for network design without the need to consider margins in response to environmental changes in complicated wireless networks such as smart meters that require multi-hop operation, contributing to lower costs and simpler network configuration (i.e. no relays). High reliability communication can be achieved in relatively simple wireless networks used for disaster and crime prevention without being affected by changing conditions.


Low current consumption design technology decreases average current by 48% during standby operation (in 10-second intervals, which comprise most of the communication time).

In addition, an original high-speed radio wave check function reduces the time required for reception startup, minimizing the total time for receiver strength detection (approx. 1 msec). This further decreases current during sleep (when only the timer is ON) to 0.9 µA, 58% less than current products.


An evaluation kit with onboard ML7345 is also available along with reference design data for compact modules (i.e. circuit diagram, peripheral parts list, recommended PCB pattern), multiple test scenarios, and sample programs (simple MAC). Other useful materials, including user manuals and tools, can be downloaded from LAPIS Semiconductor’s website (registration required).










Compatible Frequencies

160MHz to 960MHz

470 to 510MHz

Modulation Method


Transfer Rate

1200 bps to 100kbps

Reception Bandwidth

1.6 kHz to 400 kHz

Coding Scheme

NRZ, Manchester 3 out of 6

Transmission Power



Receiving Sensitivity

-120 dBm @ 2.4kbps to 510MHz

-109 dBm @ 38.4kbps, 750MHz+

-120 dBm @ 2.4kbps


Built-in wakeup and address filter functions

Supply Voltage

1.8V to 3.6V (1mW)

3.3V to 3.6V (100mW)

Transmission Current

25mA @ 10mW

90mA @ 100mW

Receiving Current


Sleep Current (Internal Timer ON)



32-pin WQFN




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