An Output-Capacitorless Linear Regulator for Integrated Portable Power Solutions

This paper proposes a linear regulator that offers a very fast transient response of less than 150ns for a load step with a 100ns rise time. The voltage regulator is designed so that no output capacitor is needed to save die area and system cost. Total on-chip capacitance is a mere 3pF for this design. It also operates at very high power efficiency with only a 39 mu A quiescent current. This design can be ideal for portable applications powered by a Li-ion battery with a small to moderate digital core, such as a power management IC for cellular phones. The process used in this work is a mature 0.35 mu m BiCMOS process commonly employed for power management devices by Texas Instruments.