A digital circuit block includes first to fourth conducting segments, a digital logic, first and second conducting layers, and a dielectric layer. The first and second conducting segments are coupled to first and second supply voltages, respectively. The digital logic and dielectric layer are between the first and second conducting segments. The third conducting segment includes a first end electrically connected to the first conducting segment, a second end not electrically connected to the second conducting segment, and a first portion located at the first conducting layer. The fourth conducting segment includes a first end electrically connected to the second conducting segment, a second end not electrically connected to the first conducting segment, and a second portion located at the second conducting layer. The first and second portions and dielectric layer are formed a first capacitive element to reduce the supply voltage drop between the first and second supply voltages.