An 8–12GHz 0.92° Phase Error Quadrature Clock Generator Based on Two-Stage Poly Phase Filter with Intermediate Point Compensation

Abstract

An ultra-low phase error, low power Quadrature Clock Generator (QCG) based on two-stage Poly Phase Filter (PPF) with intermediate point compensation is proposed. With the incorporation of a RC sensing network to detect the process variation, the PPF compensates its quadrature phase error by feeding the network's output to the intermediate point. Meanwhile, output amplitude of the PPF is enhanced as a benefit of intermediate point utilization. In comparison with conventional Type-I and Type-II PPF-based QCGs, the proposed one excels in broadband phase error as a result of lowest phase/amplitude error combination in a typical process variation scenario (ΔR=±20%, ΔC=±10%). Furthermore, it stands out in power consumption performance due to its amplitude enhancement, which effectively reduces the amplification power passive PPF implementations always need. The phase error of proposed QCG is less than 0.32° at 10GHz, and no more than 0.92 ° over 8GHz-12GHz with process variations in Global Foundry 55nm CMOS process. The QCG consumes 9.6mW from a 1.2V supply voltage.