A 0.9 V Wideband SPLL With an Adaptive Fast-Locking Circuit Achieving
24.68 μs Settling Time Reduction
Abstract
A low-power wideband self-biased phase-locked loop (SPLL) is proposed
for multi-protocol SerDes applications in this letter. With the proposed
adaptive fast-locking current circuit (AFLCC), the settling time is
reduced significantly, and no extra power and jitter contribution. In
addition, a start-up module is adopted to reset the system to an optimal
initial operating frequency quickly. The proposed 1-3-GHz SPLL,
fabricated in TSMC 28-nm CMOS process and occupies a compact 0.028mm2
area. It achieves a roughly constant settling time of 5 μs over all
frequencies and division ratios range. Only 0.96 mW is consumed from a
0.9 V supply at 1 GHz frequency.