Increasing the immunity to electromagnetic interferences in a bandgap voltage reference

In this paper a bandgap reference cell with low susceptibility to electromagnetic interferences is presented. The circuit, based on a classical architecture, is modified by using a symmetrical topology amplifier in the output stage leading to a robust electromagnetic immunity, still preserving good performances in the overall bandgap circuit. Results of the simulations, carried out on the circuit extracted from the layout, are reported and compared to a classical bandgap topology. The reference circuit exhibits a 1200 mV shift for interfering signals in the frequency range of 1 MHz-4 GHz, while the shift in the modified version of the same architecture is only 6 mV in the same frequency range.