New differential difference stage and its application to band-pass filter at 10.7Â MHz with high quality factor

In this study, we present a new NMOS implementation of differential difference stage containing only eight transistors. The introduced new differential difference stage has high input impedance and low output impedance; accordingly, it can be directly cascaded without loading effect. In addition, a detailed study on the input referred noise voltage density of the proposed differential difference stage is performed and low noise design possibility is investigated. As an example, to show performance of differential difference stage, a modified band-pass filter with high quality factor is presented for intermediate frequency stage of FM receiver. Furthermore, the non-ideal, parasitic and stability analyses of the presented filter having high quality factor are surveyed and its working boundaries are determined.