Abstract
In this letter, we present the design of a fully differential direct injection locked frequency divider (D-ILFD) in 65 nm CMOS process. Based on strong coupling of multi-coupled coils, we propose a modified inductive peaking in the D-ILFD to improve the locking range with a compact core area. The proposed injection locked frequency divide-by-2 divider demonstrates an operation frequency range of 6.7 GHz for a low injected power of -8 dBm and single-ended output power of -4 dBm. With a supply voltage of 1 V, the power consumption of the D-ILFD is 2.5 mW and the power efficiency(P-out/P-DC) is 8.3%.