Bộ khuếch đại ba giai đoạn [27] sử dụng cấu trúc này cho giai đoạn thứ hai và thứ ba. Giai đoạn đầu tiên được thực hiện như một giai đoạn cửa khẩu phổ biến, cung cấp phù hợp với đầu vào tốt và tiếng ồn thấp. Tất cả các giai đoạn trong thiết kế này đơn kết thúc AC cùng. | MA CIRCUIT IMPLEMENTATIONS 215 is caused by the falling edge at the output of the source follower My which is coupled to node b through the R-C high-pass network. Similarly M2 helps to accelerate the transitions of My The output signals from the source follower cascade drive the differential pair M4 and My FET Mị acts as a voltage-controlled resistor which varies the amount of series feedback and thus the gain of this stage. The source degeneration resistor Rs improves the linearity. The AGC amplifier in 78 consists of an input buffer four DC-coupled stages of the type shown in Fig. and an output buffer. A passive on-chip R-C-R feedback network reduces the offset voltage cf. Section . The voltage Vagc is produced by an on-chip AGC circuit. In 77 a similar differential stage has been reported which is part of a three-stage LA with a bandwidth of GHz implemented in a zm GaAs-HFET technology. In contrast to Fig. this stage has no gain control and therefore the degeneration devices Rs and M5 are removed and nodes s and s are shorted together. With this modification the stage operates at its maximum gain. Furthermore this LA stage uses inductive loads for shunt peaking. BJT and HBT Technology Cherry-Hooper stage. Figure shows a simplified schematic of the bipolar gain stage reported in 86 . This stage is part of a three-stage LA which has a bandwidth of 45 GHz and is implemented in a 105-GHz SiGe-HBT technology. This type of stage is known as a Cherry-Hooper stage and has been used successfully since 1963 when the original Cherry-Hooper paper 22 was published . see 38 96 133 143 .12 Fig. BJT HBT implementation of a gain stage based on the Cherry-Hooper architecture . 86 . -The paper 22 describes the design of single-ended wideband amplifiers using an alternation of series-and shunt-feedback stages. Later this concept was extended to a differential topology and to include emitter followers see Fig. . 216 MAIN .
