Abstract

A three stage 56% power added efficiency (PAE) InGaP/GaAs HBT power MMIC for use in GSM applications (900MHz) is described. An output power of 2.7W is obtained at the connectors of the evaluation board with a single supply voltage of 3.2V. The large signal gain is in excess of 32dB and the dynamic range for power control exceeds 80 dB. The chip size of only 2mm² allows housing in a tiny plastic package (TSSOP10) which occupies less than one half of the board area compared to packaged GSM devices before. For circuit design an accurate electrothermal large-signal HBT model is used. For characterisation of large emitter area power transistors on-wafer large signal measurement techniques have been developed which assist model verification and provide new insights in the influence of harmonic load terminations. The design techniques employs two steps. In a first step on-wafer loadpull measurements provide reasonable conditions for output power, which are combined with appropriate small-signal simulations to fix th circuit topology in principal. In a second step refinements of the power performance are achieved by large-signal simulations.