Nordic Semiconductor introduces nRF21540TM, the first low-noise power amplifier

By Nordic Semiconductor

December 19, 2019 – Nordic Semiconductor announces nRF21540TM RF front-end module (FEM), the first power amplifier / low noise amplifier (PA / LNA) product, perfectly complementing Nordic ’s nRF52 and nRF53 series of Multi-protocol system-on-chip (SoC) . This RF FEM's PA provides a highly adjustable TX power boost up to +21 dBm, while the LNA provides an RX gain of +13 dB. LNA's low noise figure (NF) is only 2.5 dB, ensuring improved RX sensitivity of Nordic Bluetooth 5 / Bluetooth Low Energy / Bluetooth LE, Thread, Zigbee, and 2.4GHz RF low-power wireless solutions . For example, when combined with the nRF52840 SoC running Bluetooth Low Energy at 1 Mbps, the nRF21540 can increase RX sensitivity by 5 dBm. Combined with increased output power, the link link budget can be increased by 18 dBm. For other devices with on-chip TX power less than +8 dBm, the increase is even greater. Therefore, increasing the connection link budget can provide a longer transmission range and help reduce the number of retransmissions due to packet corruption. For all applications that may require extended range or enhanced coverage, the nRF21540 is an invaluable complementary device. Example applications include asset tracking, audio, smart home or industrial use cases.

When used with Nordic's short-range wireless SoCs, the nRF21540 can be used as a "plug and play" complementary device. The nRF21540 is connected to the antenna output of the SoC device and has two additional antenna ports for antenna diversity. The device's gain control, antenna switch, and power mode are controlled through GPIO, SPI, or a combination of both. Although nRF21540 can be used with other radios, future versions of Nordicn RF5 SDK, nRF5 SDK for Thread and Zigbee, and nRF Connect SDK will include driver support, making this device easy to use with Nordic SoCs Sex will be further enhanced.

The TX power of the nRF21540 is dynamically adjustable, and the output power can be set to 21 dBm in small steps. This ensures that the design of the application can operate at an output power within the allowable range of 1 dBm in all areas and operating conditions. During use, power settings can be dynamically controlled by the SoC to match the requirements of the current connection. For example, the Received Signal Strength Indication (RSSI) and other parameters can be monitored to determine the power requirements of a particular connection, and the TX power can be increased or decreased to manage power consumption. Any change due to temperature can be offset to stabilize the output power at the required level.

The nRF21540 can operate from a supply voltage range of 1.7 to 3.6 V. When the TX power is adjusted to +20 dBm, it provides a competitive 115 mA power value, 4.1 mA power in RX mode, and power down mode. 30 nA power. The device operates normally over a temperature range of -40 to 105 ° C and can complement Nordic's high temperature resistant nRF52833 and nRF5340 devices in applications such as professional lighting. The chip is packaged in a 4x4 mm QFN16 and is complemented by the nRF21540 IC itself. Nordic provides development boards that enable the evaluation of RF FEM performance using laboratory equipment and practical performance evaluation in conjunction with the nRF52 series devices.

Kjetil Holstad, Director of Product Management, Nordic Semiconductor, said: "Many applications benefit from the significant range expansion provided by external RF front-end modules. It is important that FEM does not compromise other features of radio performance and does not have a significant impact on battery life. Nordic With decades of rich experience in the field of low-power wireless design, our engineering team has designed a competitive RF FEM product. This FEM is optimized and perfectly complementary to the company's advanced multi-protocol SoC, its size and price Minimize the impact on BOM and board space. "

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