Multigigahertz CMOS dual-modulus prescaler IC

A low-power CMOS dual-modulus (divide-by-128/129) prescaler IC is described. The IC has been fabricated with symmetric CMOS technology that optimizes simultaneously the characteristics of both the p-channel and n-channel transistors for low-power-supply-voltage operation. Two different gate oxide thicknesses of 175 and 100 AA have been used. The best prescalar fabricated with 175-AA gate oxide functions at 2.06 GHz with 25-m W power consumption (L/sub eff/=0.5 mu m; V/sub dd/=3.5 V). Preliminary results for prescalars fabricated with 100-AA gate oxide show that 4.2-GHz operation is possible (L/sub eff/=0.4 mu m; V/sub dd/=3.5 V). Power-supply voltage as low as 1.7 V can be used for the prescalar to function at 1 GHz with a power consumption of only 4 mW.<
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