nRF21540 RF Range Extender Module to Boost Link Budget in Low Power, Short Range Applications

Nordic Semiconductors has introduced the nRF21540TM RF Front End Module (FEM), an integrated Power Amplifier/ Low Noise Amplifier, developed to perfectly complement Nordic’s nRF52 and nRF53 Series multiprotocol Systems-on-Chip (SoCs). When combined with an nRF52840 SoC running Bluetooth LE at 1 Mbps, for example, the nRF21540 improves the RX sensitivity by 5 dBm. Coupled with the increased output power, the connection link budget is raised by 18 dBm. For other devices with less than +8 dBm TX power on-chip, the improvements are even larger. The result of this combination will lead to an increase in connection link budget which offers significantly longer range and helps lower the number of retransmissions due to corrupt packages.

Features of nRF21540:

• Supports Bluetooth Low Energy, Bluetooth mesh, Thread and Zigbee (802.15.4), and 2.4 GHz proprietary protocols
• Tunable output power in small increments (up to +21 dBm)
• Offers competitive power numbers of 115 mA at TX tuned to +20 dBm, 4.1 mA in RX mode, and 30 nA in power-down mode
• +13 dB RX gain with 2.5 dB noise figure
• 2.36-2.5 GHz input frequency range
• 1.7 to 3.6 V supply range
• -40 °C to +105 °C operating temperature range

The nRF21540 can be connected to the SoC’s antenna output and has two additional antenna ports in case of further requirement. The device’s gain control, antenna switching, and power modes are controlled via GPIO or SPI or a combination of both. While the device is in use, the power settings can be dynamically controlled based on the requirement of the current connection. Any variation due to temperature can also be counteracted so the output power is stable at the desired level.

The nRF21540 can act as a valuable addition for applications such as asset tracking, audio, smart home or industrial use cases that require an increased range or robust coverage. The chip is supplied in a 4x4 mm QFN16 package and Nordic also offers development boards that enable evaluation of the RF FEM performance using lab equipment, as well as real application performance combined with an nRF52 Series device. For more information, visit the product page on the official website of Nordic semiconductors.