In this study, electrical constant stress method which is one of accelerated tests is applied to power vertical double diffused MOSFETs continued up to 6 hours. The stress induced changes of characteristic parameters (threshold voltage, mobility, etc.) of power MOSFETs are extracted. A resistive load NMOS inverter is set up and degraded power MOSFET effects on its static parameters are investigated experimentally. Besides the obtained experimental results, a simple circuit model is proposed to simulate the stress induced changes in NMOS inverter static parameters. In this manner, obtained experimental results are supported by simulation study. Proposed degradation model has ability to help designers to predict circuit reliability in the early stages of design. (C) 2015 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of Conference Committee Members of International Semiconductor Science and Technology Conference 2015 (ISSTC 2015).