Pulsed RF Life of an L-Band Power Transistor

An accelerated pulsed RF life study of the NSC-2010 L-band power transistor was started to determine suitability for an intended application. The application requires 12.5 W of output power at 1.4 GHz with a collector supply voltage of 28 V. During the study, the RF was pulsed with the pulse width being 1.5 ms, and the duty cycle 50%. Results available indicate that the median life and 0.01 percentile life of the transistor are both greater than the desired life of 1.2 X 106 hours at a junction temperature of 140°C and the electrical conditions indicated above. In addition, the predominant failure mode appears to be emitter-base shorting of the transistor due to the formation of a conductive path between the metalization and the silicon through the dielectric layer.