STMicroelectronics – Low-power RF transceiver provides link budget of more than 140dB


STMicroelectronics’ S2-LP is an ultra- low power RF transceiver intended for RF wireless applications operating at frequencies below 1GHz.

It 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 430-470MHz or 860- 940MHz bands. Devices may use the S2-LP to connect to a SIGFOXTM network.

The S2-LP is ideal for use in power- constrained products such as wireless alarm systems: it draws just 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%, making it suitable for use in battery-powered devices.

The S2-LP supports a variety of signal modulation schemes: Gaussian Frequency Shift Keying (GFSK), On-Off Keying (OOK) and Amplitude Shift Keying (ASK). The data rate of the device’s RF transmissions is programmable in a range from 300bits/s to 500kbits/s.

The S2-LP can be used in systems with channel spacing of 12.5kHz/25kHz, supporting narrowband operation.

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.


  • -130dBm receiver sensitivity
  • Excellent receiver selectivity and blocking
  • Programmable RF output power up to 16dBm
  • Programmable digital filter at receiver
  • 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


  • Low-voltage rectification
  • Automotive LED lighting
  • DC-DC converters
  • Switch-mode power supplies
  • Reverse-polarity protection
  • Low-power applications