Technique for offset voltage cancellation in MOS operational amplifiers

1985 ◽  
Vol 21 (9) ◽  
pp. 389 ◽  
Author(s):  
S.L. Wong ◽  
C.A.T. Salama
Keyword(s):  
Operational Amplifiers ◽  
Offset Voltage

scholarly journals Right-direct (BI) type wide bandpass SC ladder filter with compensation for finite amplifier gain and offset voltage

2008 ◽  
Vol 21 (2) ◽  
pp. 233-241
Author(s):  
Nikolay Radev ◽  
Kantcho Ivanov ◽  
Kalin Stanchev
Keyword(s):  
Sixth Order ◽  
Operational Amplifiers ◽  
Switched Capacitor ◽  
Offset Voltage ◽  
Op Amps ◽  
Dc Gain ◽  
Amplifier Gain

In this paper gain- and offset-compensated (GOC) modification of a sixth-order right-direct (BI) type wide bandpass switched-capacitor (SC) ladder filter is proposed. It is based on the use of simple and fast operational amplifiers (op amps) with low but precisely known and stable dc gain A. At first, the conventional integrators in the filter are replaced with GOC integrators and the unswitched capacitors in the capacitive loops are split into two capacitors. Subsequently, the nominal op amps gain value A0 is taking into account in the capacitance sizing of some appropriately chosen capacitors. .

scholarly journals Dynamic Offset Compensated Operational Amplifiers

2021 ◽  
Author(s):  
Ara Abdulsatar Assim Assim ◽  
Evgenii Balashov
Keyword(s):  
Dynamic Range ◽  
Flicker Noise ◽  
Input Voltage ◽  
High Gain ◽  
Operational Amplifiers ◽  
Analog To Digital ◽  
Offset Cancellation ◽  
Offset Voltage ◽  
Low Offset ◽  
The Given

The given work is devoted to designing and implementing different dynamic offset cancellation techniques for 50 nm technology CMOS operational amplifiers. The goal is to minimize or get rid of the effects of the offset voltage. Offset voltage exists in all differential amplifiers due to the fact that no pair of transistors can be fabricated with the same size, there is always a slight difference in their dimensions (length or width), this gives rise to an undesirable effect called offset, the value of offset voltage for cheap commercial amplifiers are in the range of 1 to 10 mV, de-spite the fact that this isn’t a significant value, due to the high gain of such amplifiers, this voltage is amplified by tens or hundreds of times, this results in clipping of the output signal and this further limits the amplifier’s maximum allowable input voltage within the given dynamic range, hence its of great importance to take this small voltage into consideration, low-offset amplifiers find applications in mixers, analog to digital converters, instrumentation devices, etc. In this thesis, by using two different techniques for removing offset voltage (chopping and auto-zeroing), five low offset operational amplifiers were designed. The implemented methods reduced the flicker noise by more than 457 times (from 9.4 nV/√Hz to 20 pV/√Hz) at 1 Hz. All the simulations were done using Cadence Virtuoso.

scholarly journals Dynamic Offset Compensated Operational Amplifiers

2021 ◽  
Author(s):  
Ara Abdulsatar Assim Assim ◽  
Evgenii Balashov
Keyword(s):  
Dynamic Range ◽  
Flicker Noise ◽  
Input Voltage ◽  
High Gain ◽  
Operational Amplifiers ◽  
Analog To Digital ◽  
Offset Cancellation ◽  
Offset Voltage ◽  
Low Offset ◽  
The Given

The given work is devoted to designing and implementing different dynamic offset cancellation techniques for 50 nm technology CMOS operational amplifiers. The goal is to minimize or get rid of the effects of the offset voltage. Offset voltage exists in all differential amplifiers due to the fact that no pair of transistors can be fabricated with the same size, there is always a slight difference in their dimensions (length or width), this gives rise to an undesirable effect called offset, the value of offset voltage for cheap commercial amplifiers are in the range of 1 to 10 mV, de-spite the fact that this isn’t a significant value, due to the high gain of such amplifiers, this voltage is amplified by tens or hundreds of times, this results in clipping of the output signal and this further limits the amplifier’s maximum allowable input voltage within the given dynamic range, hence its of great importance to take this small voltage into consideration, low-offset amplifiers find applications in mixers, analog to digital converters, instrumentation devices, etc. In this thesis, by using two different techniques for removing offset voltage (chopping and auto-zeroing), five low offset operational amplifiers were designed. The implemented methods reduced the flicker noise by more than 457 times (from 9.4 nV/√Hz to 20 pV/√Hz) at 1 Hz. All the simulations were done using Cadence Virtuoso.

scholarly journals Modeling and Simulation of Monolithic Single-Supply Power Operational Amplifiers

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4611
Author(s):  
Ivailo Milanov Pandiev
Keyword(s):  
Supply Voltage ◽  
Circuit Simulation ◽  
Operational Amplifiers ◽  
Model Parameters ◽  
Electrical Parameters ◽  
Macro Model ◽  
Offset Voltage ◽  
Macro Modeling ◽  
Versus Supply Voltage ◽  
Versus Supply

In this paper a simple PSpice (Personal Simulation Program with Integrated Circuit Emphasis) macro-model was developed, and verified for monolithic power operational amplifiers operated with a single-supply voltage. The proposed macro-model is developed using simplification and build-up techniques for macro-modeling of operational amplifiers and simulates the basic static and dynamic characteristics, including input impedance, small-signal frequency responses at various voltage gains, output power versus supply voltage, slew-rate-limiting, voltage limiting, output offset voltage versus supply voltage ripples, and output resistance. Furthermore, the macro-model also takes into account the ground reference voltage in the amplifier at a single power supply voltage. The model is implemented as a hierarchical structure suitable for the PSpice circuit simulation platform. The sub-circuit is built using standard PSpice components and analog behavioral modeling blocks. The accuracy of the model is verified by extracting the model parameters for single-supply power operational amplifier TDA2005 from ST Microelectronics as example. The effectiveness of the model is validated by comparing the simulation results of the electrical parameters with the corresponding measured values obtained by experimental testing of sample circuits. The comparative analysis shows that the relative error of the modeled large-signal parameters is less than 15%. Moreover, an error of 15% is quite acceptable, considering the technological tolerances of the electrical parameters for this type of analog ICs.

Radiation Degradation Modeling of Bipolar Operational Amplifier Input Offset Voltage in LTSpice IV

2014 ◽  
Vol 565 ◽  
pp. 138-141 ◽  
Author(s):  
A.S. Bakerenkov ◽  
V.S. Pershenkov ◽  
A.V. Solomatin ◽  
V.V. Belyakov ◽  
V.V. Shurenkov
Keyword(s):  
Ionizing Radiation ◽  
Integrated Circuits ◽  
Operational Amplifier ◽  
Dose Dependence ◽  
Space Mission ◽  
Electronic Equipment ◽  
Operational Amplifiers ◽  
Offset Voltage ◽  
Voltage Drift ◽  
Radiation Degradation

Integrated circuits are used in electronic equipment of spaceships. Therefore, they are impacted by ionizing radiation during space mission. It leads to electronic equipment failures. At present operational amplifiers are base elements of analog electronic devices. Radiation impact leads to degradation of operational amplifiers input stages. Input bias current increasing and input offset voltage drifts are the results of ionizing radiation expose of operational amplifiers. Therefore, space application electronic equipment fails after accumulation of limit dose. It isn’t difficult to estimate radiation degradation of input bias currents of bipolar operational amplifiers, but estimation of dose dependence of input offset voltage drift is more complex issue. Schematic modeling technique based on Gummel–Poon transistor model for estimation of input offset voltage drift produced by space radiation impact was experimentally verified for LM324 operational amplifier and presented in this work. Radiation sensitive parameters of Gummel–Poon model were determined using 2N2907 bipolar pnp transistor.

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