Large-signal modeling and characterization of a plastic packaged HBT for use in wireless portable units

A method is presented for the extraction of an accurate large-signal model for plastic-packaged GaAs HBTs. The packaged device model is extracted by a combination of DC and small-signal on-wafer characterization of the chip device and small-signal characterization of short and open package structures through on-wafer probing of ceramic launchers to the package. The technique has been applied to M/A-COM's 32-finger HBT in an SOT-89 package; the resulting model shows excellent agreement with large-signal measurements for the packaged device, predicting the power and gain within 0.5 dB for a wide range of input power drive and device biases.