To provide a wideband amplifier that has flat amplification characteristics in a wide frequency range, prevents deterioration caused by parasitic capacity, and has short group delay time.
In the wideband amplifier, a band-pass filter comprising an L-C parallel resonant circuit and an L-C-R series resonant circuit is loaded in parallel as the load of a current output amplification element. The band-pass filter has a plurality of poles on an s-plane and has a zero point among the poles, and flattening characteristics in a pass band are improved. The output terminal of the amplification element becomes the output terminal as the amplifier and there are no problems of group delay. The capacitor between the output terminal of the amplifier and the GND absorbs the parasitic capacity as one portion of a constant for preventing the deterioration in frequency characteristics.
Eiji Yamada
Toshio Sawada