A passive RLC notch filter design using spiral inductors and a broadband amplifier design for RF integrated circuits

The extensive use of wireless personal communication systems has engendered considerable research interest. The current market demands low power devices, whence a need to pay attention to the passive networks within communication systems arises. In this work, notch filter designs and the broadband amplifier designs using passive circuits are analyzed and assessed.; The role of a notch filter is band-rejection to diminish the unwanted signal in the communication systems. Especially, the notch filter followed by the mixer for the image signal rejection is widely used in the front-end heterodyne receivers. Recently, passive filters have grown in importance because the active RC filters have such problems as finite gain-bandwidth product, higher electrical noise, increased power dissipation, inherent dynamic range limitations, and difficulty operating at low voltages. In this work, a new approach to realize a passive RLC notch filter using the open-circuit impedance parameters (Z-parameters) is introduced and its third order transfer voltage-gain function is analyzed to predict the performance, such as the attenuation at the notch frequency and the tuning of the notch frequency. The feasibility for on-chip implementation using planar on-chip spiral inductors is demonstrated. The controllability of the symmetrical notch characteristic is obtained by providing the method of pole-zero cancellation to reduce the parasitics of the spiral inductor. A design example of front-end heterodyne receiver is shown and it is compared with that of only a low noise amplifier (LNA). HSPICE simulations that confirm the propriety of the adopted design methodology are provided.; One way to improve amplifier bandwidth entails a shunt-series peaking methodology. A broadband amplifier with the previous T-coil configuration for bandwidth extension has peaking in its frequency response due to parasitic capacitances. The peaking affects the nonlinear operation of the system and results in non-monotonic step responses. To reduce these effects, a modified T-coil configuration is proposed and is analyzed by tracing the poles and zeros in the transfer function. The effects of the component deviations are examined for the design guidelines as well.