Accurate Analysis of Temperature Effects in /c-l/BE Characteristics with Application to Bandgap Reference Sources

The inaccuracy of the analyses commonly used for predicting the temperature behavior of the IcV~ characteristics of transistors and the output of bandgap reference sources is pointed out. The problem is traced to a basic assumption implicit, in such analyses, namely that the variation of the bandgap voltage of silicon with temperature is Iinear; this assumption is shown to be of poor accuracy. By taking into account the nonlinearity in this variation, new accurate formulas tire derived. Both the previous analyses and the proposed analysis tie compared to experiment; a valuable improvement is dem. onstrated. Equations which should prove of vake in the design of bandgap reference sources and bipolar transistor temperature transducers are given. H@her order effects are discussed.