Power amplifiers (PAs) are among the most crucial functional blocks in the radio frequency (RF) frontend for reliable wireless communication. PAs amplify and boost the input signal to the required output power. The signal is amplified to make it sufficiently high for the transmitter to propagate the required distance to the receiver. Attempted advancements of PA have focused on attaining high-performance RF signals for transmitters. Such PAs are expected to require low power consumption while producing a relatively high output power with a high efficiency. However, current PA designs in nanometer and micrometer complementary metal–oxide semiconductor (CMOS) technology present inevitable drawbacks, such as oxide breakdown and hot electron effect. A well-defined architecture, including a linear and simple functional block synthesis, is critical in designing CMOS PA for various applications. This article describes the different state-of-the art design architectures of CMOS PA, including their circuit operations, and analyzes the performance of PAs for 2.4 GHz ISM (industrial, scientific, and medical) band applications.

Readerless RFID has become more significant for reliable wireless communication. The Phase Locked Loop (PLLs) are among the most crucial functional blocks in the Readerless RFID where the PLL performance greatly depend on the Charge Pump (CP). Conventional CP circuits suffer from current mismatching characteristics which generate phase offset and spurs in the PLL output signals. In order to overcome these problems, the CP current mismatch has to be minimized. An enhanced CP circuit with zero current mismatch is presented in this article adopting an ideal current mirror technique and an additional inverter to provide a rail-to-rail voltage. The post-layout simulation shows that the proposed CP maintain the steady current over a wide range of output voltage from 0.1-1.8 V consuming the substantially lower power of 0.178 µW. The CP circuit is designed in 130 nm CMOS process that operates at 1.8 V and the core occupies 17 x 59.5 μm². The proposed CP will be a good solution for low voltage, high-frequency PLL structure which suffers from poor performances.