0.9mW 7GHz and 1.6mW 60GHz frequency dividers with locking-range enhancement in 0.13µm CMOS

Frequency dividers are key components for frequency synthesis in wireless and wireline communication systems. Among different types of frequency dividers, LC-based injection-locked frequency dividers (ILFDs) feature high- frequency operation at low power consumption, but their locking range is quite narrow due to the high-Q nature of the resonator. Recently, design techniques to enhance the locking range of ILFDs have been reported. Injection into two coupled LC oscillators and sandwiched injection into two identical LC oscillators are proposed, but these techniques are suitable for dividers with quadrature outputs. Inductive-peaking and transconductance enhancement techniques are also used but they require extra inductors and thus larger chip area. In this paper, a simple but effective technique is presented to improve the locking range of ILFDs without extra inductive components while consuming low power.