This paper describes a phase noise reduction method with hybrid phase detection in the design of semidigital 螖危 phase-locked loops (PLLs) that employ a finite impulse response (FIR) filtering technique for quantization noise reduction. A static phase offset problem is addressed and the use of a hybrid phase detector is proposed to further enhance noise and spur reduction performance. It is also shown that the FIR filtering not only suppresses out-of-band quantization noise but also improves in-band noise by mitigating the nonlinearity effect of the charge pump. Behavior simulation results show that the proposed semidigital 螖危 PLL improves the in-band noise and reference spur performance by 20dB compared with the conventional 螖危 PLL.