Input collapse of CMOS logic gates with a series-connected MOSFET chain

We propose a generic series-connected MOSFET chain model (SMCM) extending the PDSMM, to describe the peculiar DC characteristics of a series MOSFET chain. Initial state propagation delays (ISPD) are defined as propagation delays due to initial states of intermediate nodes of a series-connected MOSFET chain. Two extreme and important ISPD, called as fast ISPD and slow ISPD, are introduced. The effect of input patterns of CMOS logic gates on propagation delays in the two ISPD is discussed. Finally, an efficient mapping algorithm for every possible input pattern to an equal input ramp is introduced.