High-efficiency power amplifier module with nobel biasing circuit for W-CDMA handsets

A high efficiency two-stage power amplifier (PA) module for 1.95GHz W-CDMA handsets has been developed in 6(W) x 6(D) ×1.7(H) mm size. The module includes nobel biasing circuits with depletion-mode heterojuntion FETs to compensate temperature dependence of a quiescent drain current (Iq). An excellent power-added efficiency (PAE) of 50.3% was obtained with a gain of 25dB, under 3.5V operation while fulfilling the W-CDMA criteria. In the ambient temperature ranging from -30°C to +85°C, the PA shows little variation on an adjacent channel leakage power ratio, operation drain current and Iq. When the PA was operated at as low as 1V, it also exhibited PEA more than 28% in the ambient temperature ranging from -30°C to +85°C with a low output power of 15dBm.