Chumakov, V. E. <br/><br/>
Design features of Op-amp based on bipolar transistors for anti-aliasing active LPF with a low systematic component of zero offset voltage 

 - Vol.15(3), Jul 
 - Telangana  IUP Publications  2022 
 - 24-41p. 
<br/><br/> The zero offset voltage in anti-aliasing Low-Pass Filters (LPF) included in the Analog-to-<br/>Digital Conversion (ADC) input has a significant effect on its effective bit rate. The paper<br/>discusses methods for minimizing the systematic component of zero offset voltage (VOS)<br/>of Operational Amplifiers (Op-Amp) in the structure of the LPF due to the degradation of<br/>the current gain of the base (<br/>) of bipolar transistors for an extremely common subclass<br/>of Op-Amp with one high-impedance node. Methods for matching a high-impedance<br/>Op-Amp node and a buffer amplifier with the help of Special Correcting Multipolars<br/>(SCM) of p-(SCMp<br/>) and n-types (SCMn ) are proposed. Methods of description and<br/>formation of the given coefficients of weak current asymmetry of typical Op-Amp<br/>functional units [Current Mirrors (CM), Input Differential Stage (IDS), Buffer Amplifiers<br/>(BA), Reference Current Sources (SRC), etc.] are presented. The considered circuit<br/>technique is also recommended for Op-Amp based on wide-band Heterojunction Bipolar<br/>Transistor (HBT)-Junction Field Effect Transistor (JFET) technological processes that<br/>implement field-effect (JFET) and Bipolar Junction Transistors (BJT) on a single chip,<br/>especially when the influence of bipolar transistors on VOS needs to be compensated. As<br/>an example, the results of computer simulation of GaAs Op-Amp with small VOS performed<br/>on JFET field and p-n-p bipolar transistors are given. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Electrical Engineering