Tail-injected divide-by-4 quadrature injection locked frequency divider

Abstract

This article presents a divide-by-4 quadrature 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 quadrature voltage-controlled oscillator (QVCO) with NMOS cross-coupled switching pairs, two tail MOSFETs and TAI-C tanks, and was fabricated in the 0.35 μm 2P4M CMOS technology. The divide-by-4 LC-tank ILFD is performed by injecting an external signal to the common gate of tail MOSFETs of two coupled VCOs. Measurement results show that at the supply voltage of 2.3 V, the divider free-running frequency is tunable from 0.36 to 1.51 GHz, and at the incident power of 0 dBm the locking range is about 4.6 GHz, from the incident frequency 1.44–6.04 GHz. The core power consumption is 29.37 mW. The die area is 0.976 × 0.812 mm2.