The present invention relates to an output driver circuit for a semiconductor memory device, in particular, a memory device using a DDR II concept or a concept similar thereto, which can reduce a variation in the slew rate of an output driver thereof between maximum and minimum values, while satisfying requirements of characteristics associated with slew rate. The support members include opposing ends and a body portion, and further include an exterior channel and a central bore, the channel defining a flange portion and the bore being in communication with a retention feature. The tip of the tooth of the gear to be in mesh with a triangular tooth formed in the plate trigger is made sharp.