Techniques and systems for determining an output waveform at an output of a complementary metal-oxide-semiconductor (CMOS) logic gate are described. Some embodiments can identify at least one set of inputs of the CMOS logic gate that, when switched together, causes multiple transistors coupled in parallel to simultaneously turn-on and drive the output of the CMOS logic gate. Next, the embodiments can determine a set of current source models that are coupled in parallel to model the CMOS logic gate when the set of inputs of the CMOS logic gate are switched together. The embodiments can then simulate the set of current source models together to determine the output waveform at the output of the CMOS logic gate when the set of inputs of the CMOS logic gate are switched together.