Tunable wide-band second-order all-pass filter-based time delay cell using active inductor

This paper presents a CMOS RF second-order voltage-mode all-pass filter (APF) as a time delay cell. The proposed filter benefits from a simple structure; consisting of one transistor, three resistors, and one grounded capacitor and inductor. The filter reaches a group delay of 60 ps over a 10 GHz bandwidth, while achieving maximum delay-bandwidth-product (DBW) and it consumes only 10.3 mW power. On the other hand, an active inductor is used in the APF instead of a passive RLC tank in order to control the time delay and improve the size. In this case, the power consumption increases while time delay can be tuned. The proposed APF is designed and simulated in a TSMC 180 nm CMOS process