A monolithic 3.7 W silicon power amplifier with 59% PAE at 0.9 GHz

Low-cost and highly-efficient RF power amplifiers with high output power are necessary for today's mobile communications. However, monolithic integrated silicon bipolar RF power amplifiers have not yet been reported operating at high power-added efficiency (PAE) around 60%. To date, only GaAs MMICs, GaAs hybrid modules or Si power-MOS modules have been reported. The reasons for this are conduction losses, switching losses and charge-storage effects of the silicon bipolar power transistor. Further, at low supply voltages around 3 V, the on-chip interstage matching circuit is critical for high PAE and high output power. This work presents an integrated 2-stage RF power amplifier for the 0.8-1 GHz band based on spiral on-chip transformers. The application target for this power amplifier IC is a GSM mobile. The chip is fabricated in a standard 25 GHz-f/sub T/, 0.8/spl mu/m, 3-layer-interconnect silicon bipolar production technology.