Abstract: A limiting transimpedance amplifier includes an amplifier stage including a feedback resistor, a limiting diode coupled across the feedback resistor, and a stabilization diode coupled to the amplifier stage to compensate for feedback instability introduced by the limiting diode. The amplifier stage includes an input transistor and an output transistor, where the feedback resistor couples an output of the output transistor to an input of an input transistor. A stabilization voltage generator is coupled to the stabilization diode to provide a stabilization voltage that causes the desired compensation.

Abstract: A complementary composite PNP transistor includes a p-channel JFET and an operational amplifier coupled to form an ideal PNP transistor. The positive input of the operational amplifier forms the base of the composite transistor and the drain of the JFET forms the collector of the composite transistor. The anode of a diode-connected NPN transistor forms the emitter of the composite transistor, while the cathode is coupled to the source of the JFET. The diode-connected transistor provides complementary current-voltage characteristics for the composite PNP transistor since the saturation current and g.sub.m of the composite transistor are equal to that of an NPN transistor.

Abstract: A high-frequency differential amplifier is provided with a pair of buffer input stages, each having transistors the transconductance of which may be varied by varying a current source connected thereto. Since transistor frequency response and step response are dependent upon transconductance, bandwidth and damping factor of the step response may be varied for optimum performance without degrading gain and dynamic range characteristic of the differential amplifier. One useful application of the differential amplifier of the present invention is as an error amplifier in a cascomp amplifier circuit, such that the apparent damping factor of the step response of the cascomp circuit may be adjusted.

Abstract: A differential shunt feedback amplifier includes dual shunt feedback paths, with an emitter follower in each feedback path to provide a low impedance output with a well-defined gain. A common-mode current generator responsive to only the common-mode component of an input signal generates a current which offsets base current changes in the emitter followers caused by the common-mode component. The circuit is well suited for either push-pull or single-ended input operation over a wide range of frequencies.