Title :
A 10 GHz operational amplifier in GaAs MESFET technology
Author :
Larson, Lawrence E. ; Chou, C.S. ; Deakin, D.S. ; Hooper, W.W. ; Jensen, J.F. ; Thompson, M.A. ; Delaney, M.J. ; McCray, L. ; Rosenbaum, S.E. ; Pierson, D.A.
Author_Institution :
Hughes Res. Lab., Malibu, CA, USA
Abstract :
Previous implementations of high-performance op amps in GaAs technology have been hindered by low transistor g/sub m/r/sub ds/, light sensitivity, and excessive backgating, which have limited gain and bandwidth. These limitations are overcome in the circuit reported here by the use of improved processing technologies and circuit design approaches. The GaAs MESFET depletion-mode n-channel technology employs 0.2- mu m e-beam defined gates, air-bridge interconnects for low capacitance, and molecular beam epitaxy (MBE) to grow the channel layers. The average threshold voltage of the resulting FETs is -0.6 V, and the extrinsic transconductance is approximately 500 mS/mm. H/sub 21/ measurements on individual devices yield an extrapolated f/sub T/ of approximately 8 GHz. The small-signal equivalent circuit model of a 50- mu m-wide device, derived from the measured S-parameters, is shown, and the resulting element values are presented.<>
Keywords :
III-V semiconductors; field effect integrated circuits; gallium arsenide; linear integrated circuits; operational amplifiers; -0.6 V; 10 GHz; 500 mS; 80 GHz; GaAs; GaAs MESFET depletion-mode n-channel technology; S-parameters; air-bridge interconnects; circuit design; electron beam defined gates; extrinsic transconductance; molecular beam epitaxy; operational amplifier; processing technologies; small-signal equivalent circuit model; threshold frequency; threshold voltage; unity-gain frequency; Bandwidth; Capacitance; Circuit synthesis; FETs; Gallium arsenide; Integrated circuit interconnections; MESFETs; Molecular beam epitaxial growth; Operational amplifiers; Threshold voltage;
Conference_Titel :
Solid-State Circuits Conference, 1989. Digest of Technical Papers. 36th ISSCC., 1989 IEEE International
Conference_Location :
New York, NY, USA
DOI :
10.1109/ISSCC.1989.48184
