A 0.03mm/sup 2/ 9mW Wide-Range Duty-CycleCorrecting False-Lock-Free DLL with Fully Balanced Charge-Pump for DDR Interface

Abstract

A duty-cycle-correcting false-lock-free DLL for DDR interface is proposed. A fully balanced charge-pump equalizes the charge and discharge pulses of the phase detector to reduce update noise. The DLL achieved 49% to 51% duty-cycle output from a 30% to 70% duty-cycle input clock operating from 20 to 300MHz, consumes 9mW from a 2 to 4V supply, and occupies 0.03mm2 in a 0.30mum CMOS process