TY - GEN
T1 - Theoretical investigation on the effect of individual stage-gain selection on the 3-dB bandwidth of three-op-Amp difference amplifiers
AU - Aldisi, Reem S.
AU - Jaber, Fadi T.
N1 - Publisher Copyright:
© 2016 IEEE.
PY - 2016/9/22
Y1 - 2016/9/22
N2 - The differential gain of a three-op-Amp difference amplifier is determined by the product of the gain values of its two stages. Usually, the total desired differential gain is assigned to the first stage while the gain of the second stage is set to unity in order to achieve higher common mode rejection ratio (CMRR) values. On the other hand, the effect of this choice on the frequency response of the amplifier is not fully understood. For this purpose, this paper presents a theoretical study on the influence of gain choice for the first and second stages of the amplifier on its 3-dB bandwidth. To achieve this, the closed-loop transfer function of the amplifier is derived while considering the effect of the finite open-loop gain and bandwidth of the op-Amps used to implement this type of amplifier. The equations presented here demonstrate that the 3-dB bandwidth is increased considerably when the gain of the first stage is reduced and that of the second stage is raised while keeping the value of the total differential gain constant. Although this happens at the expense of CMRR, designers of this type of amplifier should consider the tradeoff between the two.
AB - The differential gain of a three-op-Amp difference amplifier is determined by the product of the gain values of its two stages. Usually, the total desired differential gain is assigned to the first stage while the gain of the second stage is set to unity in order to achieve higher common mode rejection ratio (CMRR) values. On the other hand, the effect of this choice on the frequency response of the amplifier is not fully understood. For this purpose, this paper presents a theoretical study on the influence of gain choice for the first and second stages of the amplifier on its 3-dB bandwidth. To achieve this, the closed-loop transfer function of the amplifier is derived while considering the effect of the finite open-loop gain and bandwidth of the op-Amps used to implement this type of amplifier. The equations presented here demonstrate that the 3-dB bandwidth is increased considerably when the gain of the first stage is reduced and that of the second stage is raised while keeping the value of the total differential gain constant. Although this happens at the expense of CMRR, designers of this type of amplifier should consider the tradeoff between the two.
KW - 3-dB bandwidth
KW - finite op-Amp bandwidth
KW - finite open-loop gain
KW - three-op-Amp difference amplifier
UR - https://www.scopus.com/pages/publications/84992049072
U2 - 10.1109/ISCAIE.2016.7575055
DO - 10.1109/ISCAIE.2016.7575055
M3 - Conference contribution
AN - SCOPUS:84992049072
T3 - ISCAIE 2016 - 2016 IEEE Symposium on Computer Applications and Industrial Electronics
SP - 155
EP - 158
BT - ISCAIE 2016 - 2016 IEEE Symposium on Computer Applications and Industrial Electronics
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 2016 IEEE Symposium on Computer Applications and Industrial Electronics, ISCAIE 2016
Y2 - 30 May 2016 through 31 May 2016
ER -