Divide-by-3 injection-locked frequency divider implemented with active inductor

This article presents a wide locking-range divide-by-3 injection-locked frequency divider (ILFD) employing tunable active inductors (TAIs), which are used to extend the locking range and to reduce die area. The CMOS ILFD is based on a voltage-controlled oscillator (VCO) with cross-coupled switching pairs and TAI-C tanks, and was fabricated in the 0.18-mu m IP6M CMOS technology. The divide-by-3 function is performed by injecting differential signal to the gates of two injection MOSFETs with the drains connected to the VCO outputs and with grounded sources. Measurement results show that at the supply voltage of 1.8 V, the divider free-running frequency is tunable from 1.20 to 1.284 GHz, and at the incident power of 4 dBm the locking range is about 1.9 GHz (45.2%), from the incident frequency 3.3 to 5.2 GHz. The core power consumption is 12.96 mW. The die area is 0.45 x 0.513 mm(2). (c) 2008 Wiley Periodicals, Inc.