Design of a low EMI susceptibility CMOS transimpedance operational amplifier

EMI Susceptibility Issue in Analog Front-End for Sensor Applications

“…Interferences in the Analog Circuits In recent years, the effects of the conveyed EMI were carefully investigated both theoretically and experimentally in order to find possible prevention methodologies [17][18][19][20][21][22][23][24][25], in particular, in high-performance digital/analog ICs that may include several operational amplifiers. The most sensitive circuits to EMI are, indeed, the analog ones and, among them, the OpAmps.…”

“…The amplifier is in the voltage follower configuration, as reported in the literature [21][22][23] and shown in Figure 2, since it is the worst case condition, because the input differential pair experience the largest disturbance. One of the most undesirable effects of interferences is the shift of the output DC mean value (offset) that may asymptotically force the amplifier to saturation [23][24][25]. Furthermore, among all the possible interfering signals the ones superimposed on the input pins of the operational amplifier are the most difficult to prevent [24,25].…”

EMI Susceptibility of a Digitally Based Analog Amplifier in a 180-nm CMOS Process

“…The amplifier under test is connected in the voltage follower configuration, as reported in the literature, since it is a worst-case condition when EMI susceptibility is considered [12], [13]. One of the most undesirable effects of the EMI is the shift of the output dc mean value (offset) which asymptotically forces the amplifier to saturation.…”

High EMI Resistivity CMOS Operational Amplifier

“…This assumption represents a worst-case condition, because the interfering signal often decays with time. Furthermore, the amplifier is in the voltage-follower configuration, as reported in [3] and [4], as it is a worst-case condition [3] as well. The undesirable effects concerning about interferences is the shift of the output dc mean value (offset) that may asymptotically force the amplifier to saturation, as depicted in Fig.…”

“…The most sensitive circuits to EMI are, indeed, the analog ones and, among them, the Op Amps [3]. In literature, it has been demonstrated that a successful approach to reduce the EMI susceptibility of the Op Amp is the adoption of symmetrical topologies [4][5]; unfortunately, the high EMI resistance architectures presented in previous works are unsuitable for the low voltage supply of the current ICs, due to the cascode connections. Therefore, recently, other solutions were proposed to intrinsically improve the resistivity of the amplifiers.…”