An exact expression for the noise resistance R/sub n/ for the Hawkins bipolar noise model

A simple, but exact formula for R/sub n/ has been presented for the Hawkins noise model of the bipolar transistor. This formula can be used in conjunction with the Hawkins formula for F/sub min/, R/sub s1opt/, and X/sub s1opt/ to provide a complete set of equations for representing the low-medium frequency range noise performance of a bipolar transistor in chip form. The authors caution that the range of validity of the derived expression for R/sub n/ should be confined to that of the Hawkins model, itself. In practice, the neglected equivalent circuit parameters in the Hawkins model and the effect of embedding the chip in a package must be taken into account at higher frequencies.<>