A four transistor layout can include an isolation region that defines an active region, the active region extending along first and second different directions. A common source region of the four transistors extends from a center of the active region along both the first and second directions to define four quadrants of the active region that are outside the common source region. Four drain regions are provided, a respective one of which is in a respective one of the four quadrants and spaced apart from the common source region. Finally, four gate electrodes are provided, a respective one of which is in a respective one of the four quadrants between the common source region and a respective one of the four drain regions. A respective gate electrode includes a vertex and first and second extending portions, the first extending portions extending from the vertex along the first direction and the second extending portions extending from the vertex along the second direction.