A complementary SiGe HBT on SOI low dropout voltage regulator utilizing a nulling resistor

The present work focuses on reducing dropout voltage and noise by exploiting the unique advantages of a complementary silicon-germanium (SiGe) heterojunction bipolar transistor (C-SiGe HBT) on SOI technology. We also explore the impact of utilizing different PNP device types on regulator performance. Design challenges arose from the off-chip load capacitor required to meet the specification of the instantaneous peak output voltage drop. To overcome these challenges, a right-hand plane (RHP) to left-hand plane (LHP) zero conversion technique with a nulling Miller resistor was applied. The complete solutions for the locations of the converted left-hand plane zero and the Miller pole affected by the nulling resistor were derived utilizing signal flow graphs without any assumptions commonly made in the literature. Two C-SiGe LDO regulators with two different types of PNP output devices were fabricated utilizing a commercially-available C-SiGe on SOI technology, and compared with the literature.