Through-Silicon Via-Based Capacitor and Its Application in LDO Regulator Design

Using coaxial through-silicon technologies, a new 3-D capacitor integrated on a silicon interposer is proposed. The capacitance of coaxial through silicon via (CTSV) capacitors is extracted, analyzed, and compared. The results obtained from the analytical model and the finite-element method exhibit good agreement with various design parameters, and the error between the proposed model and measurement remains less than 7.41%. Due to high capacitance density up to 22.4 nF/mm(2), the 3-D capacitor is adopted as a decoupling capacitor for the on-chip low-dropout (LDO) regulator design. The proposed LDO is developed in a 180-nm CMOS technology and shows unique advantages regarding the power supply rejection (PSR) performance, quiescent current, and area compared with that of the conventional LDOs with off-chip capacitors and capacitor-less (CL) LDOs.