Parametric yield loss has become a serious concern in leakage dominated technologies. In this paper, we discuss the impact of leakage on parametric yield and show that leakage can cause yield window to shrink by imposing a two-sided constraint on the window. We present a mathematical framework for yield estimation under device process variation for a given power and frequency constraints. The model is validated against Monte Carlo simulations for an industry process and is shown to have typical error of less than 5%. We then demonstrate the importance of optimal supply voltage selection for yield maximization. We also investigate the sensitivity of parametric yield to applied frequency and power constraints. Finally, we apply the proposed framework to the problem of maximizing the shipping frequency in the presence of given yield and power constraints.