A low power injection-locked divider for body sensor network

This paper presents a low power 866 MHz injection-locked frequency divider (ILFD) based on UMC 0.18 μm CMOS process. Unlike high-cost off-chip inductor ILFD, on-chip spiral inductor and MOS varactor are used. The ILFD is based on dual cross-coupled LC voltage controlled oscillator (VCO) with direct injection for tail transistor. Compared to NMOS/PMOS-only oscillators, cross-coupled VCO enables low-power operation by doubling transconductance, the supply voltage of cross-coupled VCO can be also as low as 0.6 V. It is about 0.6 mW (without output buffers) under supply voltage of 0.8 V. When the injected input signal power is 0 dBm, direct ILFD features a wide locking range of 100 MHz. The ILFD still has a locking range of 10 MHz when the injected input signal power is -10 dBm. It can be used as the driver stage of power amplifier in transmitter systems for body sensor network.