A scalable DC model of lateral double diffused MOSFETs (LDMOSFETs) is presented in this paper. This model is based on physical analysis considering device geometry, carrier distributions, mobility degradation effect, and the effect of impact ionization. In this model, we divide the LDMOSFET into two regions to obtain the physical conduction model: one is channel region and the other is drift region. The channel region model is based on the BSIM3v3 model and the drift region employs voltage dependent resistance model considering the length of depleted region in the drift region. The modeling results are compared with measured I-V characteristics and the results show good agreements with the maximum error of 10% compared to the measured results of devices.