Abstract: A differential amplifier comprises two input transistors and two cross-coupled transistors arranged in a translinear loop. A difference voltage across a resistance connected between the emitters of the cross-coupled transistors is equal to a difference voltage across the input terminals plus the sum of the offset voltages across resistors arranged in series with the respective emitters of the input transistors. The difference current through the cross-coupled transistors is replicated in output transistors, thereby producing an output signal amplitude larger than the input signal amplitude across a resistance coupled between the emitters of the output transistors. The differential amplifier is suitable, inter alia, as an interpolating residue signal amplifier with additional underflow and overflow ranges in multi-step dual-residue analog-to-digital converters.

Abstract: A differential voltage-current converter has two input transistors and two cross-coupled transistors arranged in a translinear loop, the difference voltage across the emitter resistors of the cross-coupled transistors being equal to the difference voltage across the input terminals. The difference current through the cross-coupled transistors is replicated in the output transistors, thereby enabling a larger output signal amplitude to be obtained. In order to increase the permissible input voltage the bases of the cross-coupled transistors are coupled to the input transistors via emitter-followers. By connecting the collectors of the emitter-followers to the collectors of the output transistors a compensation is obtained for the decreasing current gain at high frequencies.

Abstract: A track-and-hold circuit includes an input stage (IS), an output stage (OS) and a switching stage (SS). The switching stage is coupled between the input stage and the output stage. The switching stage includes a switching transistor (T10), a differential amplifier (T11/T12), a current source (T13/R11), and a capacitor (C11). In order to improve the frequency response, the input stage is provided with a passive impedance coupled between a base of the switching transistor and a first supply terminal (1) and the input stage is adapted to supply a signal current to the base of the switching transistor. This signal current is related to an input signal applied to the input stage. The output stage includes a first output transistor (T14), a first current source (T15) switched by a tracking signal (Vt), a second output transistor (T16), and a second current source.

Abstract: A current amplifier has an input terminal (1) for an input current (Iin) to be amplified in order to obtain a first output current (Iout1) at a first output terminal (2) via a first transistor (T1) and a second output current (Iout2) at a second output terminal (8) via a current mirror (6). A diode-connected transistor (T5) is coupled between the emitter of the first transistor and the input terminal of the current amplifier so as to improve the current branching at the input terminal, thereby extending the bandwidth and the output swing of the current amplifier.