Navigating 5G Complexity: Understanding Power Class 2 In RF Front-End Design

Since our last discussion of Power Class 2 (PC2) in 2017, the cellular market has rapidly advanced, introducing foldable phones, 5G New Radio (NR), and complex carrier aggregation (CA) techniques. The latest 3GPP specifications now integrate PC2 into Frequency Division Duplex (FDD) bands, enabling higher transmit power for 5G devices, especially in high-frequency ranges. PC2, which originally supported high-power user equipment (HPUE) in 4G LTE, addresses challenges related to propagation loss and signal coverage in higher frequency bands, improving network efficiency.

PC2 devices can transmit at a maximum of 26 dBm, offering improved coverage and network performance compared to the default PC3 class (23 dBm). While higher power improves signal strength, it also introduces RF challenges, such as increased power consumption, thermal management, and the risk of signal interference. Additionally, PC2 systems must ensure compliance with regulatory limits for specific absorption rates (SAR), which measure the amount of RF energy absorbed by the human body.

To address these challenges, RF front-end designs need efficient solutions that minimize losses, manage heat, and avoid interference. Companies like Qorvo are developing integrated modules, such as RF Flex™ and RF Fusion™, that combine filters, switches, and power amplifiers to reduce matching losses and optimize link budgets. Additionally, BAW filters enhance performance by providing superior attenuation and low insertion loss, critical for carrier aggregation and PC2 applications. These innovations help engineers meet the power and efficiency demands of modern 5G devices, ensuring robust performance in increasingly complex designs.