Development of a wideband amplifier for use in a measurement system for the detection of prebreakdown pulses in solid dielectrics

A high-gain wideband amplifier was needed for a system that measures prebreakdown pulses in solid dielectrics. This paper describes the development of an amplifier for this pulse measurement system. The amplifier has a voltage gain of 99 (40 dB) and a bandwidth extending from 130 Hz to 115 MHz. The small-signal rise time of the amplifier is 3.2 ns and the rise time is 4.4 ns for a 1-Volt pulse into a 50 ohm load. Designs for wideband amplifiers developed over the last ten years were reviewed, and a configuration was selected and modified for this application. Circuit biasing was described, and extensive AC and noise analyses were conducted. The results of these analyses were compared with those obtained from a computer model for the circuit. The circuit was fabricated and experimental results are included along with suggestions for improving the design.