The Design of a Low-Voltage Bandgap Reference [The Analog Mind]

Most integrated circuits incorporate bandgap references (often simply called bandgaps) to define certain dc voltages or currents that serve various building blocks. In this article, we introduce a step-by-step procedure for the design of low-voltage bandgaps. As presented in Figure 1, a typical power-management environment employs a low-dropout (LDO) circuit that, from a global supply of 1.2 V, generates a moderately regulated voltage around 1 V. This voltage acts as a local supply for the bandgap circuit and some other building blocks. It is desirable for the bandgap to provide substantial supply rejection to minimize corruption in its output due to the electronic noise produced by the LDO and the transient perturbations caused by the switching activities within the other building blocks.