Tutorial: Design of Voltage References

Voltage references are indispensable components in IC design. Their applications range from simple biasing to providing adequate accuracy for ADCs, DACs, VFCs, and other building blocks. In this tutorial, bandgap reference (BGR) fundamentals and the design of CMOS BGRs will be covered. Topics include classic BGRs, op-amp based and non-op-amp based BGRs; BGRs with and without output buffers; stability issues arose from negative and positive feedback; loop-gain function and power-supply rejection; startup issues, trimming and design of resistor strings. Advanced topics include curvature compensation, sub-1V references, micropower references, and alternatives to bandgap references such as fully CMOS references and resistor-less references.