A Low-Jitter Injection-Locked Multi-Frequency Generator Using Digitally Controlled Oscillators and Time-Interleaved Calibration

Abstract

This paper presents a low-jitter, injection-locked frequency generator that can provide multiple output frequencies concurrently. The injection-locked digitally controlled oscillators (DCOs) can be controlled separately so that their output frequencies can be changed independently between 0.9 and 1.2 GHz in 15-MHz steps. Due to the proposed time-interleaved frequency calibrator that operates continuously in the background, all injection-locked DCOs are ensured to maintain excellent jitter performance against process, voltage, and temperature (PVT) variations. As a prototype, the proposed injection-locked, multi-frequency generator (ILMFG) was designed to generate two independently controlled output signals, and it was fabricated in a 65-nm CMOS technology. The 1-MHz phase noise and the rms jitter integrated from 1 kHz to 40 MHz of the 960-MHz output signal were -133.5 dBc/Hz and 375 fs, respectively. The degradation of rms jitter was restricted to less than 10%. The silicon area was 0.05 mm(2), and the total power consumption was 7.7 mW when generating two different output frequencies.