Accurate and Fast Testing Technique of Operational Amplifier DC Offset Voltage in µV-Order by DC-AC Conversion

Author(s):  
Yuto Sasaki ◽  
Tamotsu Ichikawa ◽  
Anna Kuwana ◽  
Kazumi Hatayama ◽  
Haruo Kobayashi ◽  
...  
Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1157 ◽  
Author(s):  
Robert Chebli ◽  
Mohamed Ali ◽  
Mohamad Sawan

We present in this paper a fully integrated low-noise high common-mode rejection ratio (CMRR) logarithmic programmable gain amplifier (LPGA) and chopped LPGA circuits for EEG acquisition systems. The proposed LPGA is based on a rail-to-rail true logarithmic amplifier (TLA) stage. The high CMRR achieved in this work is a result of cascading three amplification stages to construct the LPGA in addition to the lower common-mode gain of the proposed logarithmic amplification topology. In addition, the 1 / f noise and the inherent DC offset voltage of the input transistors are reduced using a chopper stabilization technique. The CMOS 180 nm standard technology is used to implement the circuits. Experimental results for the integrated LPGA show a CMRR of 140 dB, a differential gain of 37 dB, an input-referred noise of 0.754 μ Vrms, a 189 μ W power consumption from 1.8 V power supply and occupies an active area of 0.4 mm 2 .


Doklady BGUIR ◽  
2021 ◽  
Vol 19 (4) ◽  
pp. 52-60
Author(s):  
O. V. Dvornikov ◽  
V. A. Tchekhovski ◽  
V. L. Dziatlau ◽  
Y. D. Galkin ◽  
Nikolay N. Prokopenko

Structured arrays and master slice arrays are often used to reduce cost, design and test time for radiation hardened analog integrated circuits. One of such master slice arrays is МН2ХА030, which uses bipolar and junction field-effect transistors. The purpose of this article is to estimate the effect of ionizing radiation on the parameters of the operational amplifier OAmp2 and comparators ADComp1 and ADComp3 created on the МН2ХА030 master slice array. Еhe results of measurements of analog components after exposure to 60Co gamma quanta with an absorbed dose of up to 700 krad and a fast electron fluence of up to 2.9·1015 el./cm2 with an energy of 6 MeV are presented. The OAmp2 operational amplifier provides a satisfactory level of basic static parameters (input current, offset voltage, voltage gain) at a fast electron fluence of up to 3.7·1014 el./cm2 with an energy of 6 MeV. There are a decrease in the voltage gain and an increase in the offset voltage at electron fluence of greater than 1015 el./cm2. The latter can be caused by a decrease in the efficiency of the common-mode signal feedback integrated into operational amplifier with a significant drop in current gain of bipolar transistors. All considered analog components provide a satisfactory level of basic static parameters at a fast electron fluence of up to 3.7·1014 el./cm2 with an energy of 6 MeV and an absorbed dose of 60Co gamma quanta of at least 700 krad. It is assumed that resistance of OAmp2, ADComp1, ADComp3 to the action of 60Co gamma quanta is significantly higher and requires further research. The developed analog components can be used in signal reading devices required in front-end of sensors for space instrumentation and nuclear electronics.


Author(s):  
Nicholas Konkol

Abstract Series capacitors, under certain conditions, within high speed differential pair signals were found to have negative effects on mother board functions inside a personal computer (PC). It was noted in one case study that three conditions affected capacitors with this type of application: capacitor aging, DC offset voltage, and cold temperatures. These conditions led to the decrease in capacitance which then disabled the network connection inside the PC. It was concluded that a strategically chosen capacitor type alleviates these conditions. The capacitor type primarily depends on the dielectric material.


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