Clock buffers and clock inverters are usually balanced optimally for a better clock distribution. Other cells like muxes are optimized for avoiding glitches. Lots of good reasons not to use conventional cells.
Clock buffers and clock inverters are usually balanced optimally for a better clock distribution. Other cells like muxes are optimized for avoiding glitches. Lots of good reasons not to use conventional cells.
1. In the early days of CTS you wanted the clock to arrive to every flop at the exact same time. So you had to balance the rising and falling paths along the clock tree to make it happen. Nowadays this is less important as CTS tries to exploit clock skew on purpose.
2. Transistor order, essentially.