A Single-Chip WCDMA Envelope Reconstruction LDMOS PA with 130MHz Switched-Mode Power Supply

This paper presents a single-chip ER circuit for cellular applications. It includes a high-band PA and its switched-mode supply modulator on the same silicon die, which avoids the need for an external GaAs chip. The differential PA reaches 60% PAE at 31dBm with a 1.95GHz carrier. The supply modulator is a single- coil SMPS with no additional linear amplifier. It features a 15MHz AC bandwidth without pre-distortion thanks to its 130MHz PWM and achieves 83% peak efficiency at 2W output power. The overall transmitter peak PAE with a WCDMA signal is 49% at 27dBm and at 3.6V supply voltage. Careful PCB implementation keeps switching harmonics below -60dBc. The ER system achieves -39/-47dBc 1st/2nd ACLR and rms EVM below 4% at 27dBm without pre-distortion, in compliance with WCDMA requirements.