triquint semi hfet application notesIn the application notes, Triquint introduces : TriQuint Semiconductor has developed a range of Heterostructure FETs designed for power amplifier applications where high power-added efficiency is a key specification. They also offer the unique possibility to construct amplifiers with high efficiency and low intermodulation products near compression. This technical note describes how power amplifiers may be designed using this device, and includes a specific design example. The reader is referred to Ref 1 and Ref 2, which describe the structure and properties of the device and contain measured data from a number of HFET power amplifiers. Copies of Ref 2 are available from TQS Microwave GaAs Products (MGP) on request.

The TQS HFET family consists of four devices with different gate peripheries (see below). One gate and one drain pad are provided per 1.2 mm of gate periphery for each device with gates to the left and drains to the right. Sources are connected to the backside of the chip using via holes. Extra gate and in some cases elongated drain pads are provided to allow devices, connected in parallel to achieve higher power levels, to be interlinked to avoid odd-mode oscillations.

Devices should be soldered to the baseplate using Au/Sn eutectic. It is recommended not to exceed 300 deg C for greater than three minutes during soldering. For experimental purposes only, epoxy mounting has been used. The use of epoxy will result in slightly degraded performance due to the higher device operating temperature. This will also have a negative effect on device lifetime, of course.

For more details about the semiconductor application note in pdf , including the information on descrete HFETs, TGA4230, TGA4240, TGA4250, TGA4260, specifications, typical DC characteristics, device selection and characterization, bias point, optimum load impedance, recommended setting for representing load impedance, output network design, input network design, intermodulation performance of class AB hfet amplifiers, hybrid implementation of HFET amplifiers, graphical representation of maximum and minimum inductance, monolytic implementation, design file output, hfet power amplifier design example, test fixture for capacitor loss measurement, download the pdf document free from the following application notes collection:

Triquint Semiconductor Application Notes pdf : Designing High Efficiency Amplifiers using HFETs Download

[source : triquint.com]