A new ultra low voltage dynamic floating input D flip-flop (DFIDFF) is proposed for high speed prescaler circuit. Prescaler and VCO are the main blocks that determining the speed of phase locked-loop (PLL). In this paper, a very low power-delay product divide-by 4/5 prescaler based on our DFIDFF is proposed. The prescaler implemented with 0.13 mum 1P8M N-well CMOS process with an ultra low 0.5 V power supply voltage. By HSPICE simulation results, the power-delay product (PDP) of the novel divided-by 4/5 prescaler can be reduced over 39% in comparison to conventional divided-by 4/5 prescaler. Moreover, the novel divided-by-4/5 prescaler circuit can operate at 613 MHz with the power consumption of 8.014 uW under a 0.5 V supply voltage.
2006 The 13th IEEE International Conference onElectronics, Circuits and Systems (ICECS '06),pp.902 - 905