A wideband Injection Locked Frequency Divider based on a process and temperature compensated ring oscillator

We describe a divide-by-4 injection-locked frequency divider (ILFD) based on a novel process and temperature compensation technique. The ILFD possesses a wide locking range over process corners and a wide temperature range due to the proposed compensation technique. The core of the ILFD consists of ring oscillator based on a modified version of symmetric load (Maneatis) delay elements. A calibration circuitry can be used to further enhance the locking range. Measurement results show that the proposed ILFD functions as a divide-by-4 circuit for an input frequency range from 1.8 GHz to 3.2 GHz for a power level as low as -3 dBm. The worst-case power consumption was approx. 2 mW from a 1.8 V power supply. The proposed ILFD can be used as a low-power prescaler for multi-band applications.