A fully integrated pulse width modulator for Class-S power amplifiers

Abstract

A fully integrated pulsewidth modulator for Class-S power amplifiers is presented. It consists of a triangular signal generator, a comparator and output buffer. The HBT BiCMOS design of PWM circuit is applied to the LTE frequency range, which converts digitally modulated 955MHz RF carrier with 2.87GHz sampling clock. This PWM shows an EVM 6.6%, a differential output voltage swing 1.35Vp-p with 62.7mA dissipating at 3.3V power supply.