An inductorless PLL with 1/2- and 1/4-integral as well as integral subharmonic injection locking is realized, which can solve tradeoff between the selectable frequency step and phase noise of injection-locked PLLs (ILPLLs).The proposed ILPLL was fabricated in 90nm CMOS process (PLL area: 0.083mm2, tuning range: 1.1–2.0 GHz). For a 80MHz reference, it shows that the 1-MHz-offset phase noise is -106 dBc/Hz at 1.8 GHz (= 11:25 160 MHz) with injection.
A 15-dB reduction is achieved, compared with that in the case without injection.