Sumitomo – Power Device Mounting Considerations

A 10-W, GaN HEMT SEDI device is found to be useful for designs from low frequencies up to 5 GHz. A design example over a subband of this performs over more than one octave at lower frequencies. The device is biased class AB. A linear single-ended amplifier for broadband UHF applications using the EGN010MK was designed. The approach uses a series RC on the input to improve gain flatness. Data from the resulting design is reported. > Read More

 
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Paul E. White – Component Distributors, Inc.

Sumitomo – High Power GaAs FET Amplifiers: Push-Pull versus Balanced Configurations

Abstract:
Various methods of combining high power “push-pull” devices are often possible. Two methods, push-pull and balanced configurations, are theoretically discussed. A practical example with a push-pull and a balanced amplifier using the same 150 W, S-band GaAs device(1) is reported and amplifier data are compared and analyzed. Various methods of combining high power “push-pull” devices are often possible. Two methods, push-pull and balanced configurations, are theoretically discussed. A practical example with a push-pull and a balanced amplifier using the same 150 W, S-band GaAs device(1) is reported and amplifier data are compared and analyzed.
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Sumitomo – High-Power GaAs FET Device Bias Considerations

The purpose of this application note is to give some general basic guidelines to bias high-power GaAs FET devices safely. However these guidelines are not a complete insurance against oscillations since each device is a unique case and its stability has to be analyzed by using standard methods if needed.

While considerable effort is spent by the semiconductor companies on characterizing high-power GaAs FET devices in RF and how to match them, little effort is spent for the bias techniques. Experience shows that a lot of amplifier designers spend significant time trying to solve stability problems. These problems are due to the fact that high-power devices have very large gate periphery and consequently large transconductance. Several issues specific to high-power devices have to be addressed for the design of the bias circuits and for the turn-on and –off sequences of these devices.

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