Soft computing-based approach for optimal design of on-chip comparator and folded-cascode op-amp using colliding bodies optimization

2016 ◽  
Vol 29 (5) ◽  
pp. 873-896 ◽  
Author(s):  
Bishnu Prasad De ◽  
R. Kar ◽  
D. Mandal ◽  
S. P. Ghoshal
Keyword(s):  
Optimal Design ◽  
Soft Computing ◽  
Op Amp ◽  
Colliding Bodies Optimization ◽  
Folded Cascode ◽  
On Chip

A 1-mm2 CMOS-pipelined ADC with integrated folded cascode operational amplifier

2020 ◽  
Vol 37 (4) ◽  
pp. 205-213
Author(s):  
Norhamizah Idros ◽  
Zulfiqar Ali Abdul Aziz ◽  
Jagadheswaran Rajendran
Keyword(s):  
Operational Amplifier ◽  
Open Loop ◽  
Cmos Process ◽  
Silicon Area ◽  
Content Type ◽  
Op Amp ◽  
Dc Gain ◽  
Input Range ◽  
Folded Cascode ◽  
The Impact

Purpose The purpose of this paper is to demonstrate the acceptable performance by using the limited input range towards lower open-loop DC gain operational amplifier (op-amp) of an 8-bit pipelined analog-to-digital converter (ADC) for mobile communication application. Design/methodology/approach An op-amp with folded cascode configuration is designed to provide the maximum open-loop DC gain without any gain-boosting technique. The impact of low open-loop DC gain is observed and analysed through the results of pre-, post-layout simulations and measurement of the ADC. The fabrication process technology used is Silterra 0.18-µm CMOS process. The silicon area by the ADC is 1.08 mm2. Findings Measured results show the differential non-linearity (DNL) error, integral non-linearity (INL) error, signal-to-noise ratio (SNR) and spurious-free dynamic range (SFDR) are within −0.2 to +0.2 LSB, −0.55 LSB for 0.4 Vpp input range, 22 and 27 dB, respectively, with 2 MHz input signal at the rate of 64 MS/s. The static power consumption is 40 mW with a supply voltage of 1.8 V. Originality/value The experimental results of ADC showed that by limiting the input range to ±0.2 V, this ADC is able to give a good reasonable performance. Open-loop DC gain of op-amp plays a critical role in ADC performance. Low open-loop DC gain results in stage-gain error of residue amplifier and, thus, leads to nonlinearity of output code. Nevertheless, lowering the input range enhances the linearity to ±0.2 LSB.

Optimal design of nonlinear large-scale suspendome using cascade optimization

2017 ◽  
Vol 33 (1) ◽  
pp. 3-18 ◽  
Author(s):  
Ali Kaveh ◽  
Masoud Rezaei ◽  
MR Shiravand
Keyword(s):  
Optimal Design ◽  
Large Scale ◽  
Simple Procedure ◽  
Geometry Optimization ◽  
Steel Structures ◽  
Optimization Method ◽  
Scale Space ◽  
Cross Sectional ◽  
Colliding Bodies Optimization ◽  
Design Variables

Large-scale suspendomes are elegant architectural structures which cover a vast area with no interrupting columns in the middle. These domes have attractive shapes which are also economical. Domes are built in a wide variety of forms. In this article, an algorithm is developed for optimum design of domes considering the topology, geometry, and size of member section using the cascade-enhanced colliding bodies optimization method. In large-scale space steel structures, a large number of design variables are involved. The idea of cascade optimization allows a single optimization problem to be tackled in a number of successive autonomous optimization stages. The variables are the optimum height of crown and tubular sections of these domes, the initial strain, the length of the struts, and the cross-sectional areas of the cables in the tensegrity system of domes. The number of joints in each ring and the number of rings are considered for topology optimization of ribbed and Schwedler domes. Weight of the dome is taken as the objective function for minimization. A simple procedure is defined to determine the configuration of the domes. The design constraints are considered according to the provisions of Load and Resistance Factor Design–American Institute of Steel Constitution. In order to investigate the efficiency of the presented method, a large-scale suspendome with more than 2266 members is investigated. Numerical results show that the utilized method is an efficient tool for optimal design of large-scale domes. Additionally, in this article, a topology and geometry optimization for two common ribbed and Schwedler domes are performed to find their optimum graphs considering various spans.

Design of a New Folded Cascode Op-Amp Using Positive Feedback and Bulk Amplification

2007 ◽  
Vol E90-C (6) ◽  
pp. 1253-1257 ◽  
Author(s):  
M. ASLONI ◽  
K. HADIDI ◽  
A. KHOEI
Keyword(s):  
Positive Feedback ◽  
Op Amp ◽  
Folded Cascode
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