A Flip-Chip Silicon IPMOS Power Amplifier and a DC/DC Converter for GSM 850/900/1800/1900 MHz Systems

An LDMOS-based MOS device, called integrated power MOS (IPMOS), was developed to provide integration of high-performance reliable RF power devices with the rest of the front-end using flip-chip packaging. A 3-stage power amplifier (PA) die containing 1-8-30 and 1-8-40 mm wide IPMOS devices was designed for GSM 1800/1900 and GSM 850/900 MHz systems, respectively. The PA for GSM 850/900 achieved power added efficiencies (PAE) in the range of 54 to 62 % across the band with output power (P_out) ranging from 34.5 to 35.4 dBm when driven with input power (P_in) greater than 3 dBm. The PA for GSM 1800/1900 achieved PAEs in the range of 39 to 42 % with Pout ranging from 32.5 to 33.7 dBm when driven with P_in greater than 4 dBm. A DC/DC buck converter was also designed using the same process, and the bias to the PA for GSM 850/900 was applied through this converter. PAEs when P_in and DC/DC converter output voltage are varied were compared.