Bandpass ΣΔ modulators using LC resonators typically require an active Q-enhancement circuit in order to achieve a higher resolution. However, the Q-enhancement circuit operating at GHz range suffers from finite speed due to power constraints. In this paper, the effects of finite gain-bandwidth of the Q-enhancement circuit in bandpass ΣΔ modulators are analyzed, and a mathematical model is derived. The model quantitatively clarifies the two kinds of distortion in the noise transfer function due to finite gain-bandwidth, namely a shift of the in-band zeros and an out-of-band peaking. Compensation is then applied such that the original noise shaping is retained. Consequently, Q-enhancement circuit can be designed with a smaller gain-bandwidth in order to reduce its power consumption.