Monolithically integrated filter circuit

摘要

A monolithically integrated filter circuit having low transmission losses and a high upper cutoff frequency has at least one charged transfer device with a closed loop transmission channel provided on a doped semiconductor body to which transmission channels of branch charge transfer devices are connected at predetermined nodal points. Each charge transfer device has shift electrodes arranged over an insulating layer over a limiting surface of the semiconductor body which are charged with clock voltages. Shift electrodes in the immediate proximity of a nodal point are charged with the same clock voltage but are separately allocated to different transmission channels and have a pre-determined surface area ratio with regard to each other and the sum of their surface areas is equal to the surface area of an adjacent shift electrode which is allocated to the closed loop transmission channel. The transmission channel of a branch charge transfer device at a nodal point is disposed at an angle with respect to the transmission direction of the closed loop transmission channel which is approximately 45 DEG .