A monolithic wide-band GaAs IC amplifier

The design and performance of a general purpose, monolithic, wide-band GaAs IC amplifier is described. This amplifier features a high-voltage gain (26 dB), wide bandwidth (5 MHz to 3.3 GHz), and very low input: VSWR (less than 1.3:1). No matching components are used on-chip, allowing for a small chip size of /SUP 1///SUB 4/ mm/SUP 2/. The input stage consists of a 248 /spl mu/m MESFET in a common-gate configuration with a noise figure under 10 dB (f=1 GHz) with a 50 /spl Omega/ source resistance. Noise figure limitations of both common-source and common-gate MESFET stages are discussed in detail. The amplifier uses 1 /spl mu/m gate length MESFETs, GaAs Schottky diodes for level shifting, thin-film silicon nitride capacitors for AC coupling, and GaAs implanted resistors. The high gain and wide bandwidth make this amplifier useful for many signal processing and instrument/measurement applications.