An Improved SAR Controller for Fast Locking and Relocking All Digital DLL

All digital delay-locked loops are widely used to solve the clock skew in modern day VLSI. However, the conventional SARDLL has the dead-lock problem, which limits its applications. So an improved SAR controller without dead-lock is proposed by embedding a restarting module into the conventional SAR controller. Using the improved SAR controller, a fast locking and relocking all digital SARDLL is implemented in 0.18μm CMOS . Post-layout transistor-level simulation results show that the lock-in and relock-in time are both within N cycles of input clock for N-bit SAR controller.

[1]  Shen-Iuan Liu,et al.  A fast-lock mixed-mode DLL using a 2-b SAR algorithm , 2001, Proceedings of the IEEE 2001 Custom Integrated Circuits Conference (Cat. No.01CH37169).

[2]  Shen-Iuan Liu,et al.  A 40–550 MHz Harmonic-Free All-Digital Delay-Locked Loop Using a Variable SAR Algorithm , 2007, IEEE Journal of Solid-State Circuits.

[3]  S. Moorthi,et al.  A novel 14 ∼ 170 MHz All digital delay locked loop with ultra fast locking for SoC applications , 2011, 2011 IEEE Recent Advances in Intelligent Computational Systems.

[4]  Ching-Che Chung,et al.  A wide-range all-digital delay-locked loop in 65nm CMOS technology , 2010, Proceedings of 2010 International Symposium on VLSI Design, Automation and Test.

[5]  Shen-Iuan Liu,et al.  Clock-deskew buffer using a SAR-controlled delay-locked loop , 2000, IEEE Journal of Solid-State Circuits.

[6]  Yoshinori Okajima,et al.  Digital Delay Locked Loop and Design Technique for High-Speed Synchronous Interface (Special Issue on ULSI Memory Technology) , 1996 .

[7]  Hongyi Chen,et al.  An Implementation of Fast-Locking and Wide-Range 11-bit Reversible SAR DLL , 2010, IEEE Transactions on Circuits and Systems II: Express Briefs.

[8]  Xin Chen,et al.  A Harmonic-Free All Digital Delay-Locked Loop Using an Improved Fast-Locking Successive Approximation Register-Controlled Scheme , 2009, IEICE Trans. Electron..

[9]  Chun-Yuan Cheng,et al.  An improved SAR controller for DLL applications , 2006, 2006 IEEE International Symposium on Circuits and Systems.