A detailed analysis of nonideal effects on high precision bandgap voltage references

Until recently a closed-form expression for the output voltage of the most basic bandgap references was not available making it difficult to analytically and systematically determine the effects of the temperature dependence of non-ideal components on the magnitude of the output voltage, on the inflection point location, and on the curvature of these bandgap circuits. In this paper several non-ideal components that can adversely affect the performance of bandgap references are identified. A systematic approach is proposed to analytically determine the effects of the temperature dependence of non-ideal components. Analytical expressions for the effects of two of the most common non-ideal components, the temperature-dependent gain-determining resistors and the amplifier offset voltage, on the temperature characteristics of basic band-gap circuits are developed. The effectiveness of the analytical expression is validated by comparing analytical results with simulation results obtained from Spectre.