High voltage lateral DMOS transistors are very di⁄cult to model due to the complex structure. As a result of complexity and the range of variation in transistor structure no general LDMOS model exists. Standard SPICE models of MOSFETs, JFETs together with a resistor have been used in the sub-circuit model. Self-heating e¡ects have been included in a specially design unit. The model shows good overall accuracy.