A novel waveform generating for generating a waveform having symmetrical rise and fall times. The waveform generator of the present invention includes a first current source, a second current source, a MOS capacitor and a clamping circuit. The first current source and the second current source are coupled to a node such that current generated by the first current source flows into the capacitor and current generated by the second current source flows out of the capacitor. The clamping circuit is also coupled to the node such that the output voltage generated by the waveform generator is limited to a minimum and a maximum value. Therefore, by controlling the current flowing into the node, and the capacitance at the node, the rate at which the output voltage changes over time is controlled. As such, a waveform having very precise rise and fall times is generated.