© 2013 IEEE. Mixed-signal 3D-ICs have a stacked structure of digital and analog circuit chips. In this study, the effect of noise propagation from a digital circuit on an analog circuit was evaluated using an actual mixed-signal 3D-IC. The noise propagation via through-silicon vias (TSVs) was measured, with a ring-oscillator as a noise source. For a comprehensive investigation, TSV-liner interface states were evaluated along the depth direction using unique multiwell-structured TSVs and a charge-pumping method. It was considered that the interface traps and nonconformal thickness of the TSV liner increased the noise propagation among stacked chips.