The main purpose of the input stage of an operational amplifier is to amplify differential signals and to reject common-mode input voltages. An important specification of an input stage is the common-mode input range. If the common-mode voltage is kept within this range, the input stage will properly respond to small differential signals. Hence, an application has to be designed such that the common-mode input voltage stays within the common-mode input range. Other important specifications of the input stage are the input referred noise, offset and the common-mode rejection ratio.


Tail Current Current Mirror Input Stage Strong Inversion Current Switch 
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Copyright information

© Springer Science+Business Media Dordrecht 1996

Authors and Affiliations

  • Ron Hogervorst
  • Johan H. Huijsing
    • 1
  1. 1.T.U. DelftThe Netherlands

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