STMicroelectronics – Low-power 868MHz transceiver provides robust air interface in Sigfox networks


STMicroelectronics’ S2-LP, a low- power RF transceiver operating at frequencies below 1GHz, enables designers to implement wireless equipment designs intended for use in Sigfox networks. The S2-LP also supports the Wireless M-Bus protocol and includes an embedded packet handler to implement proprietary wireless protocols.

The S2-LP is suitable for use in the licence-free ISM and Short-Range Devices (SRD) frequency bands at 433MHz, 868MHz and 920MHz, but can also be programmed to operate at other frequencies in the 430 to 470MHz or 860 to 940MHz bands.

This frequency coverage is suitable for use in Sigfox networks: Sigfox uses ultra-narrowband technology operating in 200kHz of bandwidth in licence-free spectrum: 868 to 869MHz or 902 to 928MHz depending on the region. The S2-LP is capable of supporting narrow channel spacing down to 12.5kHz.

The S2-LP transceiver also provides built-in support for Frequency-Shift Keying (FSK) modulation, which is one of the two modulation schemes that may be applied to Sigfox transmissions – the other is phase-shift keying.

System designers will find the S2-LP’s low-power operation ideal for use in battery- powered Sigfox nodes: it draws less than 7mA when receiving, and 10mA when transmitting at an output power of 10dBm. It also has a very efficient power-management circuit. An integrated switching regulator provides for operation from a 1.8V to 3.6V input at a power- conversion efficiency of 90%.

The S2-LP offers an RF link budget of more than 140dB, providing for long-range communication in many applications. It meets the regulatory requirements applicable in territories worldwide, including Europe, Japan, China and the US.

ST also supplies the BALF-SPI2-01D3, a small balun which features matching impedance configured specifically for the S2-LP.


  • -130dBm receiver sensitivity
  • Excellent receiver selectivity and blocking
  • Programmable RF output power up to 16dBm
  • Programmable digital filter at receiver
  • 500kbits/s maximum data rate
  • Battery indicator and low-battery detector
  • Automatic packet acknowledgment and retransmission
  • Antenna diversity algorithm
  • Flexible packet length with dynamic payload length
  • Supports Wireless M-Bus protocol


  • Smart metering
  • Home energy-management systems
  • Wireless alarm systems
  • Smart home systems
  • Building automation equipment
  • Industrial monitoring and control
  • Smart lighting systems

Orderable Part Number: STEVAL-FKI868V1