Abstract: A circuit according to an example includes an immitance converter amplifier based on a plurality of transistors of a first conductivity type and a supply transistor coupled between an output of the immitance converter amplifier and a supply for a supply potential, the supply transistor being a transistor of a second conductivity type complementary to the first type.

Abstract: A circuit according to an example includes an immitance converter amplifier based on a plurality of transistors of a first conductivity type and a supply transistor coupled between an output of the immitance converter amplifier and a supply for a supply potential, the supply transistor being a transistor of a second conductivity type complementary to the first type.

Abstract: According to one or more aspects of the present invention, an amplifier arrangement is disclosed. The arrangement comprises a first, a second and a third amplifier. The first and second amplifiers are coupled to one another such that they form a negative feedback loop. In addition, an output node of the first amplifier is connected to a signal input of the third amplifier. An output node of the third amplifier circuit forms the amplifier output of the amplifier arrangement. In addition, the third amplifier circuit is designed for switchably changing its gain on the basis of a signal at an actuating input of the amplifier arrangement.

Abstract: An amplifier arrangement is provided having a first differential amplifier stage and a second differential amplifier stage, which are connected to one another with negative feedback. The second differential amplifier stage has a first voltage divider that is connected to the controlled path of the second differential amplifier stage and has at least two signal taps. The second differential amplifier stage also has a second voltage divider with at least two signal taps. Furthermore, a switching device is provided, and is connected to the at least two signal taps of the first voltage divider and to the at least two signal taps of the second voltage divider. The switching device is used to connect one of the at least two signal taps of the first voltage divider to a first output tap of the amplifier arrangement, and one of the at least two signal taps of the second voltage divider to a second output tap of the amplifier arrangement. The overall input impedance can thus be adjusted in a suitable preferred manner.

Abstract: Provision is made of a differential amplifier arrangement with a current source (S1), two controllable paths (T1, T2), which are in each case coupled by one terminal to the current source (S1) and the control terminals of which form the input of the differential amplifier arrangement. Via a respective cascode circuit (K1, K2), a load (L1, L2) is respectively connected to the first and second controllable paths (T1, T2). At least one tap (A1) between one of the loads and one of the cascode circuits forms an output of the differential amplifier arrangement. Provision is made of a comparison means (D1) having two inputs, which is designed for outputting a control signal dependent on a comparison. A first input is coupled to the first tap (A1) and the second input is designed for feeding a reference signal.

Abstract: A low-noise amplifier circuit is specified which has a switchable gain ratio. For this purpose, a parallel circuit comprising a first and a second current path (3, 4) is provided between a radio-frequency signal input and output (1, 2), with the first current path (3) having a transistor which is connected in a common-base circuit for signal amplification, and the second current path (4) having a transistor which is connected in a common-emitter circuit (7) for signal amplification, and has input impedance matching (25, 27). Owing to the good noise characteristics and the good linearity characteristics, the described low-noise amplifier circuit is suitable for use in radio-frequency receivers in which adaptive pre-amplification is required even before a frequency converter, that is to say at the radio-frequency level, because the input signal has a wide dynamic range, such as that in the case of UMTS.

Abstract: An amplifier arrangement is provided having a first differential amplifier stage and a second differential amplifier stage, which are connected to one another with negative feedback. The second differential amplifier stage has a first voltage divider that is connected to the controlled path of the second differential amplifier stage and has at least two signal taps. The second differential amplifier stage also has a second voltage divider with at least two signal taps. Furthermore, a switching device is provided, and is connected to the at least two signal taps of the first voltage divider and to the at least two signal taps of the second voltage divider. The switching device is used to connect one of the at least two signal taps of the first voltage divider to a first output tap of the amplifier arrangement, and one of the at least two signal taps of the second voltage divider to a second output tap of the amplifier arrangement. The overall input impedance can thus be adjusted in a suitable preferred manner.