USE OF BICMOS-TECHNIQUES IN LOW-VOLTAGE O PERATIONAL-AMPLIFIERS

We will present an overview of the use of BiCMOS-Techniques in low-vol tage operational amplifiers. Focus will be on input-, intermediate- an d output-stages as well as on a voltage generator circuit. The disadva ntages of rail-to-rail input-stages built of complementary differentia l amplifiers will be discussed. An input-stage with improved performan ce, that uses an on-chip generated additional voltage, will be shown. The drawbacks of rail-to-rail class-AB output-stages and methods to co ntrol the quiescent current will be considered. A rail-to-rail voltage -follower output-stage using the generated additional voltages for bia sing will be proposed. The on-chip voltage generator will be presented . Finally, we will direct toward the total circuit of the proposed low -voltage operational amplifier.