The nRF21540 is an RF front-end module (FEM) for Bluetooth® LE, Bluetooth mesh, 2.4 GHz proprietary, Thread, and Zigbee range extension.
When combined with an nRF52 or nRF53 Series System on Chip (SoC), the nRF21540 RF FEM’s +21 dBm TX output power and 13 dB RX gain ensure a superior link budget for up to 16x range extension.
The nRF21540’s TX power is dynamically adjustable and output power can be set 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. The LNA has a low noise figure of 2.5 dB that ensures improved RX sensitivity.
The nRF21540 FEM has a 50Ω SubMiniature Version A (SMA) input and 2x 50Ω SMA outputs. This enables connecting an SoC or a signal generator to the input. It also enables connecting the outputs to measurement tools or to antennas directly. The FEM can be configured through the pins available on the Arduino headers.