Study On The Pulse Effect And Mechanism Of Microwave Low Noise Amplifier

Semiconductor devices and integrated circuits have some intrinsic weakness and vulnerablility, which demonstrate low survival rate under the conditions of external electrical stress. Aimming at the pulse effect mechanism of the semiconductor devices and integrated circuits, the second-breakdown effect and safety area of bipolar devices are studied, and the result shows that in depletion region of collector junction, the current consists of conduction current and displacement current. The rising or falling edges of pulse could induce a sharp increase of displacement current and may even break the collector junction. The signals in common use, such as the rectangular waveform, triangular waveform, sinusoidal waveform are analysed with respect to signal energy, power and power spectra. Among the three waveforms, the superior of rectangular waveform is evidently seen. It would be chosen as the pulse input signal due to its highest energy density of power spectra, and it is the pulse signal that could affect the reliability of the semiconductor devices and integrated circuits most. The negative effect to the reliability of semiconductor devices and integrated circuits is called pulse effect in the paper, which induced by the rising or falling edges of pulse,Based on the theoretical analysis, the A-, B3, B5, B5B four series of microwave low noise amplifier are analysed, and the characteristic and potential weakness of the interior circuits under the pulse effect are located in this paper. Two kinds of LNA were chosen to have the pulse effect experiments respectively. Based on the two experiments results, the paper finds that the rectangular pulse series in low power could induce the pulse effect of the devices and integrated circuits, which confirms the analysis of the theory.Finally,the paper uses the ADS software as the main tool to study the pulse effect, and qualitatively simulate the four kinds of microwave low noise amplifiers above mentioned. The simulation results are very consistent with the experiments data, which is a justification of our study and shows the usefulness in the future quantitative simulation research.