The influence of the reverse Early effect on the performance of bandgap references

Abstract

In the literature three key-parameters are commonly used for the design of bipolar bandgap references: EG (bandgap energy), IS (saturation current) and XTI (exponent of the temperature behavior of IS). This paper shows that four key parameters exist: these three and VAR,the reverse Early voltage. This parameter models the influence of the base-width modulation at the base-emitter junction on the collector current. A general expression for the error in the output voltage caused by the reverse Early effect is derived and a comparison is made with other errors.