The nRF21540 from Nordic Semi is an RF front end module for Bluetooth Low Energy, Bluetooth mesh, Thread & Zigbee range extension and other 2.4 GHz Applications. This FEM consists of a Power Amplifier, Low Noise Amplifier and two switches that connect to two separate antenna ports. It improves the range and connection robustness of Nordic Semi's portfolio of short-range wireless modules/SOCs (nRF52 and nRF53 Series).
On the Tx side, the power level of the FEM is dynamically adjustable up to 21 dBm in small increments. This ensures that designs can run with output power within 1 dBm of the allowable range across all regions and operating conditions. On the Rx side, it provides a gain of 13 dB with a noise figure of 2.5 dB. The module requires a DC supply voltage from 1.7 to 3.6 V and draws 115 mA in Tx mode and 4.1 mA in Rx mode.
The nRF21540 is qualified at a temperature range from -40 to 105°C. It also includes two antenna ports for antenna diversity support. When combined with an nRF52 or nRF53 Series SoC, it provides up to 16x range extension and has a sensitivity of -100 dBm. This chip is available in a 16-lead 4x4 QFN package and is suitable for smart home, asset tracking, audio, and industrial applications.
When combined with an nRF52840 SoC running Bluetooth Low Energy at 1 Mbps, for example, the nRF21540 improves the RX sensitivity by 5 dBm to -100 dBm. Coupled with the increased output power, the connection link budget is raised by 18 dBm. For nRF52 and nRF53 Series devices with less than +8 dBm TX power on-chip, the improvements are even larger, reaching 16x longer range.