Development and characterization of a high frequency low noise amplifier

In this paper we describe the design, implementation and performance of a low noise cascode amplifier. This amplifier is characterized in term of equivalent input voltage noise density and voltage gain at different drain currents upto a frequency of 80 MHz. The equivalent input voltage noise density of this amplifier is measured by two techniques. In the first technique, the output noise spectrum is downconverted to an intermediate frequency and the noise voltage is acquired using a data acquisition card interfaced with LabView software. Whereas, in the second technique, a spectrum analyzer is used to measure the equivalent input voltage noise density. The equivalent input voltage noise desnity measured by both techniques is found to be less than (1.8 ± 0.2) nV/√Hz in the band (30-80) MHz.