A 0.5 V fully differential gate-input operational transconductance amplifier with intrinsic common-mode rejection

2006 ◽  
Author(s):  
M. Abdulai ◽  
P. Kinget
Keyword(s):  
Operational Transconductance Amplifier ◽  
Common Mode ◽  
Fully Differential ◽  
Transconductance Amplifier ◽  
Gate Input

scholarly journals A Complementary Recycling Operational Transconductance Amplifier with Data-Driven Enhancement of Transconductance

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1457 ◽  
Author(s):  
Xiang Li ◽  
Bo Hou ◽  
Chunge Ju ◽  
Qi Wei ◽  
Bin Zhou ◽  
...  
Keyword(s):  
Cmos Technology ◽  
Data Driven ◽  
Experimental Result ◽  
Slew Rate ◽  
Operational Transconductance Amplifier ◽  
Common Mode ◽  
Fully Differential ◽  
Transconductance Amplifier ◽  
Good Potential ◽  
Fast Settling

An improved operational transconductance amplifier (OTA) is presented in this work. The fully differential OTA adopts the current recycling technique and complementary NMOS and PMOS input branches to enhance the total transconductance. Moreover, in order to achieve higher current efficiency, a data-driven biasing circuit was developed to dynamically adjust the power consumption of the amplifier. Two comparators were added to detect the voltage difference at the input nodes, and when the differential input is large enough to activate either comparator, extra biasing current is activated and poured into the amplifier to enhance its slew rate and gain-bandwidth product (GBW). The threshold voltage of the complementary recycling folded cascode (CRFC)-based comparator is configured to suppress overshoot. Complementary common-mode feedback (CMFB) topology with local CMFB structure is built to acquire high common-mode gain. The OTA was fabricated in SMIC 0.18- μ m CMOS technology. The experimental result based on a capacitive feedback loop shows that the data-driven operation improves the average slew rate of the amplifier from 10.2 V/ μ s to 55.5 V/ μ s while the power only increases by 150%. The OTA has good potential to satisfy the fast settling demands for capacitive sensing circuits.

Design of a New Low Power Fully Differential Amplifier with Settling Time Enhancement Characteristics

2015 ◽  
Vol 24 (06) ◽  
pp. 1550078 ◽  
Author(s):  
Seid Jafar Hosseinipouya ◽  
Farhad Dastadast
Keyword(s):  
High Performance ◽  
Settling Time ◽  
Cmos Process ◽  
Output Stage ◽  
Common Mode ◽  
Class Ab ◽  
Fully Differential ◽  
Op Amp ◽  
Transconductance Amplifier ◽  
Adaptive Biasing

High performance of fully differential operational transconductance amplifier is designed and implemented using a 0.18-μm CMOS process. The implemented op-amp uses common mode feedback (CMFB) circuit operating in weak inversion region which does not affect other electrical characteristics due to eliminating common mode (CM) levels automatically leading to improve CM rejection ratio (CMRR) of the amplifier significantly. Moreover, the output stage has class-AB operation so that its current can be made larger due to increasing the output current dynamically using adaptive biasing circuit. Additionally, the AC currents of the active loads have been significantly reduced using negative impedances to increase the gain of the amplifier. The results show the GBW 2.3 MHz, slew rate 2.6 V/μs and 1% settling time 150 ns with a capacitive load of 15 pF. This amplifier dissipates only 6.2 μW from a 1.2 V power supply.

scholarly journals Compact Continuous Time Common-Mode Feedback Circuit for Low-Power, Area-Constrained Neural Recording Amplifiers

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 145
Author(s):  
Joon Young Kwak ◽  
Sung-Yun Park
Keyword(s):  
Low Power ◽  
Continuous Time ◽  
Cmos Technology ◽  
Neural Recording ◽  
Low Noise ◽  
Common Mode ◽  
Passive Components ◽  
Fully Differential ◽  
Transconductance Amplifier ◽  
Differential Difference Amplifier

A continuous-time common-mode feedback (CMFB) circuit for low-power, area-constrained neural recording amplifiers is proposed. The proposed CMFB circuit is compact; it can be realized by simply replacing passive components with transistors in a low-noise folded cascode operational transconductance amplifier (FC-OTA) that is one of the most widely adopted OTAs for neural recording amplifiers. The proposed CMFB also consumes no additional power, i.e., no separate CMFB amplifier is required, thus, it fits well to low-power, area-constrained multichannel neural recording amplifiers. The proposed CMFB is analyzed in the implementation of a fully differential AC-coupled neural recording amplifier and compared with that of an identical neural recording amplifier using a conventional differential difference amplifier-based CMFB in 0.18 μm CMOS technology post-layout simulations. The AC-coupled neural recording amplifier with the proposed CMFB occupies ~37% less area and consumes ~11% smaller power, providing 2.67× larger output common mode (CM) range without CM bandwidth sacrifice in the comparison.

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