Abstract-To improve the immunity against process gradients, a common centroid constraint, in which every pair of capacitors which has been derived by dividing some original capacitors into two halves should be placed symmetrically with respect to a common centroid, is widely used. Xiao et al. proposed a method to obtain a placement satisfying the common centroid constraints, but this method has a defect. In this paper, we propose a decoding algorithm to obtain a placement which satisfies common centroid constraints