This paper presents a computationally efficient Raychowdhury compact model for the Schottky barrier (SB) carbon nanotube field-effect transistor (CNTFET). In order to achieve an accurate compact model, shot noise sources is added. Then, for the assessment of the SB on circuit performances, an operational amplifier (Op-Amp) is designed using the SB-CNTFET compact model, and results are compared with a conventional CNTFET.