Transimpedance Preamplifiers and Receivers with Preamplifiers

摘要

A transimpedance pre-amplifier circuit is arranged to have a complex pole response resulting from the interaction of the open-loop pole with the pole associated with a circuit feedback. The pre-amplifier circuit includes a transistor (Q1) with a load capacitor (C1) connected in the transistor output circuit to determine the open-loop pole. The feedback includes a resistive element (F). The first stage of the pre-amplifier comprising the transistor (Q1) may be followed by one or more further amplifying stages (A1, A2). The feedback to the input of the first stage may be from the output of one of the further stages. A receiver incorporating the pre-amplifier circuit (14) includes only post-amplifiers (10, 12) connected to receive the output of the pre-amplifier (14). The response of the pre-amplifier makes it unnecessary to include a dedicated passive filter in the receiver and the post-amplifiers (10, 12) can have smaller bandwidths than in conventional receivers. This makes the receiver particularly useful for use at high frequencies, for example, of the order of 1.6 GHz.