This paper proposes the proportional static-phase-error reduction (SPER) for the frequency-multiplier-based delay-locked-loop (DLL) architecture. The frequency multiplier (FM) can synthesize a combined clock to solve the high operational frequency of DLL. However, FM is sensitive to the static phase error of DLL. A SPER loop adopts a timing amplifier and a coarse-fine tuning technique to enhance the deterministic jitter of FM. The SPER loop proportionally reduces the static phase error and can extend the operating range of FM.

This paper describes a high-speed, robust, scalable, and low-cost feed-forward time amplifier that uses phase detectors and variable delay lines. The amplifier works by detecting the time difference between two rising input edges with a phase detector and adjusting the delay of the variable delay line accordingly. A test chip was designed and fabricated in 65 nm CMOS. The measured resulting performance indicates that it is possible to amplify time difference while maintaining high-speed operation.

In this paper, we propose a two-step TDC with phase-interpolator and time amplifier to satisfy high resolution at 2.4 GHz input frequency by implementing delay time less than that of an inverter delay. The accuracy of phase-interpolator is improved for process variation using the resistor automatic-tuning circuit. The gain of time amplifier is improved using the delay time difference between two delay cells. It is implemented in a 0.13 µm CMOS process with a die area of 0.68 mm2. And the power consumption is 14.4 mW at a 1.2 V supply voltage. The resolution and input frequency of the TDC are 0.357 ps and 2.4 GHz, respectively.

This paper presents a time amplifier design that improves time resolution using an inverter chain delay in SR latches. Compared with the conventional design, the proposed time amplifier has better characteristics such as higher gain, wide range, and small die size. It is implemented using 0.13 µm standard CMOS technology and the experimental results agree well with the theory.