BROADCAST_BAND_RF_AMPLIFIER

Published:2009/7/7 7:50:00 Author:May | From:SeekIC

The circuit has a frequency response ranging from 100 Hz to 3 MHz；gam is about 30 dB,Field－effecttransistor Q1is configured In the coΠ1mon－source self－biased mode. Optional resistor R1 allows you to setthe input impedance to any desired value；commonly,it will be 50 Ω.The signalis then direct coupled to Q2, a common－base circuit that isolates the input and outputstages and provides the amplifier’s exceptional stability． Last, Q3 functions as an emitter follower, to provide low output impedance at about 50 Ω．If you need higher output impedance,include resistor R8. It willaffect impedance according to this formula：R8≈ROUT -50. Otherwise,connect output capacitor C4directly to the emitter of Q3.



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