A single-loop DLL using an OR-AND duty-cycle correction technique

In this paper, we report a single-loop delay-locked loop (DLL) using a novel OR-AND duty-cycle correction (DCC) circuit. The proposed OR-AND DCC circuit employs both an analog blocks to detect duty error precisely and a digital block to control duty-error easily. To prove the proposed concepts, a single-loop DLL employing the proposed OR-AND DCC is demonstrated with SPICE simulation. The DLL using 0.1-mum CMOS process provides clocks with 16-psec peak-to-peak jitter at 1-GHz operating frequency and spends 20-mA bias current at 1.8-V power supply. The proposed DCC has the accuracy of plusmn1 % for plusmn25 % duty error and 300 cycles duty-correction time in the range of 100 MHz -1.3 GHz operating frequencies.