Analysis of a switched ultra-low power bandgap reference source for passive RFID tags

In this paper, a switched ultra-low power bandgap reference source is presented that consumes 185nA and requires a minimum supply voltage of 1.2V. Circuit details to achieve the low power dissipation are discussed and simulation results are demonstrated. Process variations are considered. The reference source is part of a passive RFID tag analog front-end that is compliant with the EPCglobal Class1 Gen2 standard. As technology, a TowerJazz 0.18 um standard logic process is used. The bandgap reference provides a supply-independent PTAT current and a bandgap voltage of 1.05V, which exhibit a minimum PSRR of 120 dBOhm and 40dB, respectively. The start-up requires 750 us.