RF Operational Life Test of Power GaAs FET Amplifiers

This paper describes the life testing of twenty-four 3/4-W, X-band, solid-state, three-stage power amplifiers through 24,000 hours. Sixteen actively driven modules were subjected to a temperature of 75°C for 24,000 hours, and eight modules started at 75°C for 8000 hours were tested at 125°C for 16,000 additional hours. Measurements of module output phase and amplitude were made at room temperature after each 1000 hours of test. No catastrophic failures occurred through 24,000 hours of testing, although one module exceeded failure limits in the 75°C test and six modules exceeded limits in the 125°C test. Average RF amplitude drift for the 75°C test modules is -0.31 dB, while standard deviation for RF phase is 9.0 degrees.