EXTRACTING 1 F NOISE COEFFICIENTS FOR BJTS

We present a method for extracting the BJT SPICE noise model parameter s AF and KF based on a general analysis of the small-signal equivalent circuit and the role of the internal BJT noise sources. The analysis is valid even for transistors with poor current gain and large base-co llector conductance, for which the output noise characteristics may no t be dominated by base flicker and shot noise. The method consists of interpreting the measured 1/f corner frequency versus dc current data in terms of the BJT's internal noisy small signal equivalent circuit. Measured data is presented for an implanted-emitter and two polysilico n-emitter bipolar technologies.