A differential HBT power cell and its model

Abstract

A differential heterojunction bipolar transistor (HBT) power cell has been designed and modeled with additional model extraction patterns. The differential power cell, which is composed of a unit differential amplifier with a common emitter ballast resistor, has no gain degradation by the ballast resistors and has been implemented in InGaP/GaAs HBT technology. DC and AC characteristics are extracted from a half circuit of the differential power cell and thermal characteristics are extracted from a common-mode circuit of that. Using the extracted model, a 5-GHz differential power amplifier has been designed and fabricated with on-chip output networks. The 5-GHz differential power amplifier delivers 26 dBm of P-IdB with 30% collector efficiency. (c) 2008 Wiley Periodicals, Inc.