X-band GaAs RF Power Amplifier Thermo Mode Research

摘要

Important parameter of high power RF integrated circuits (IC) is a high density of heat generation elements on die. It causes extremely overheating HEMT active regions, parameters, and lifetime degradation. It's important to determine to die maximum temperature as a function of timing. The research of thermo heating mode for 10W X-band GaAs RF high power amplifier was done. Scientific software and infrared SC5700 camera were used. It was shown that output stage transistors are most critical in terms of thermal mode. The paper contains maximum die temperature and output RF power as a function of the power supply duty cycle. It was shown that the duty cycle increasing from 5% to 15% causes the die temperature increasing on 30C and output RF power decreasing on 20%. Output transistors maximum temperature as a function of power supply pulse width (with a constant duty cycle) have determined. It was shown that power pulse width increasing from 25 μs to 150 μs causes die overheating on 10 - 15C and output RF power decreasing on 8 - 10%. Experimental results show good agreement with computer simulation [1]-[3].