An Active-Inductor Injection Locked Frequency Divider With Variable Division Ratio

This letter presents a wide-locking range, body-injected, injection locked frequency divider (ILFD) with tunable active inductors (TAIs) and variable division ratio. The ILFD was fabricated in the 0.18 mum 1P6M CMOS technology, and it has the modulus of 2, 3, 4, and 5, and can be used as a first-harmonic injection-locked oscillator (ILO). The divide-by-3 function is performed by injecting differential a signal to the bodies of cross-coupled transistors in the VCO. At the supply voltage of 1.5 V, the free-running divider is tunable from 0.53 to 1.72 GHz. At the incident power of 0 dBm the operation range in the first-harmonic ILO is from the incident frequency 0.53 to 3.2 GHz. The operation range in the divide-by-3 (divide-by-2) mode is about 3.59 (4.13) GHz, from the incident frequency 1.55 to 5.14 (0.87 to 5.0) GHz.