A 3 V small chip size GSM HBT power MMIC with 56 percent PAE

This article describes a three-stage 56 percent power added efficiency (PAE ) InGnP/GaAs hetero-junction bipolar transistor (HBT) power MMIC for use in Global System for Mobile Communications (GSM) applications at 900 MHz. An output power of 2.7 tli is obtained at the connectors of an evaluation boar d with a single supply voltage of 3.2 V. The large-signal gain is in excess of 32 dB, and the dynamic ra range for power control exceeds 80 dB. The ch ip size of only 2 mm(2) allows housing in a thin shrunk small outline packa ge (TSSOP10), which occupies less than one half of the board area compared to the packaged CSM devices used previously. The design is performed in two steps. First, reasonable conditions for output power can be obtained by on -wafer load-pull measurements, which, in conjunction with appropriate small -signal si simulations, a-re used to establish the basic circuit topology. Second further performance improvements are achieved by large-signal simula tions.