IEICE Transactions on Electronics
Online ISSN : 1745-1353
Print ISSN : 0916-8524
Regular Section
A 125MHz 64-Phase Delay-Locked Loop with Coarse-Locking Circuit Independent of Duty Cycle
Pil-Ho LEEHyun Bae LEEYoung-Chan JANG
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2014 Volume E97.C Issue 5 Pages 463-467

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Abstract

A 125MHz 64-phase delay-locked loop (DLL) is implemented for time recovery in a digital wire-line system. The architecture of the proposed DLL comprises a coarse-locking circuit added to a conventional DLL circuit, which consists of a delay line including a bias circuit, phase detector, charge pump, and loop filter. The proposed coarse-locking circuit reduces the locking time of the DLL and prevents harmonic locking, regardless of the duty cycle of the clock. In order to verify the performance of the proposed coarse-locking circuit, a 64-phase DLL with an operating frequency range of 40 to 200MHz is fabricated using a 0.18-µm 1-poly 6-metal CMOS process with a 1.8V supply. The measured rms and peak-to-peak jitter of the output clock are 3.07ps and 21.1ps, respectively. The DNL and INL of the 64-phase output clock are measured to be -0.338/+0.164 LSB and -0.464/+0.171 LSB, respectively, at an operating frequency of 125MHz. The area and power consumption of the implemented DLL are 0.3mm2 and 12.7mW, respectively.

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© 2014 The Institute of Electronics, Information and Communication Engineers
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