Ultra-low-power compact single-transistor all-pass filter with tunable delay capability

A novel first-order voltage-mode all-pass filter is introduced as a true-time delay (TTD) cell with tunable delay capability. The proposed filter consists of a single transistor, a varactor, and four resistors. The operation of the proposed filter is verified by post-layout simulations in 65-nm CMOS technology. The post-layout simulation results of a single stage of the proposed filter demonstrate a wideband operation range of 0.3-3 GHz and a continuously tunable delay in the range 12–40 ps. The circuit layout occupies 375 μm2 and the total power consumption of the circuit is 183.7 μW. © 2021 Elsevier GmbH