[Legacy Report] Use of the Overdrive Voltage in the Design of an Internally Matched MMIC Low Noise Amplifier

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A method of biasing low noise amplifiers using the concept of overdrive voltage, Vod is introduced. The RF parameters of different FET sizes are measured against Vod to determine the optimum biasing points for good noise figure and OIP3. It was determined that the best biasing for low noise figures is between 0.15 to 0.25V and for OIP3 is 0.28 to 0.32V. Through careful selection of the biasing architecture, this concept is then applied to the design of a low noise amplifier employing a source degeneration technique. This resulted in the design of Mini-Circuit’s PSA4-5043+ broadband low noise MMIC amplifier which is internally matched and having a typical noise figure of 0.65dB at 1 GHz and 0.9dB at 4GHz using a 0.5um pHEMT process.

Aaron Vaisman is a RF Design Engineer II at Mini-Circuits where he has been involved in the latest Mixers, Limiters, Frequency Multipliers, Couplers and Power Splitter designs. Also, he has assisted in several LNA designs. During his undergraduate studies at “Universidad de los Andes” in Bogota, Colombia, he held several TA positions on different courses on analog communications circuit design, communications theory and microwave circuits. At his first year of his masters program at Universidad de los Andes, he became assistant professor on microwave circuit design and analog communication circuits courses. Later on, as part of a joint research effort he assisted to the University of Manitoba to build in their clean room facilities a recently designed by him Dual Behavior Resonator filter with re-configurable center frequency and bandwidth. During his masters program at Columbia University, Aaron was invited by his Microwave circuits professor to work as an intern at Alcatel Lucent (Former Bell Labs) in the nano-technology group, where he designed a multimodal filter for wideband applications. He received his MSEE degree from Columbia University in 2009 and his BSEE from Universidad de los Andes in 2007. He is a member of the IEEE.

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