A family of tunable MOS resistors based on quasi-floating-gate (QFG) transistors biased in the triode region is analyzed in this paper. From the study results, a new device that outperforms previous implementations, is presented. By means of a capacitive divider, the ac component of the drain-to-source voltage scaled with a factor alpha les 1 is added to the gate-to-source voltage leading to a cancellation of the nonlinear terms. The effect of alpha on resistor linearity is analytically studied. Simulation results are also provided for different technologies. Finally, a complete transconductor has been built which preserves the linearity of the MOS resistor. Three versions of the transconductor have been fabricated for different values of alpha (alpha = 0, 0.5, and 1) in a 0.5 mum CMOS technology with plusmn1.65-V supply voltage. Experimental results show (for alpha = 1 ) a THD of - 57 dB (HD2=-70 dB) at 1 MHz for 2-V peak-to-peak differential input signal with a nominal ac-transconductance of 200 muA/V and a power consumption of 3.2 mW.

Tunable Linear MOS Resistors Using Quasi-Floating-Gate Techniques

A compact implementation of a scheme to improve linearity of MOS resistors is introduced. It is based on capacitive gate voltage averaging in conjunction with large resistive biasing elements implemented using MOS transistors operating in subthreshold. Experimental results from a test chip in 0.5 µm CMOS technology are shown that verify the proposed technique.

Linearisation of MOS resistors using capacitive gate voltage averaging

The quasi- or pseudo-floating gate (QFG) technique addresses a key issue with the floating-gate MOS transistor technique, by using ultra-high resistances to provide dc paths to otherwise floating nodes. Several ways have been suggested to implement the quasi-infinite resistors (QIRs). In this paper, basic QIR structures are analyzed and compared, and three sources of error, dc offset, signal distortion, and signal-dependent offset, are defined. Then, through simulations and experiments, the suitability of several QIR implementations for use in various applications is compared. A particular QIR implementation is found to minimize dc offset, but requires voltage swings to be limited to less than a diode turn-on voltage. Some application circuits using quasi-floating gate are presented, including a QFG translinear geometric-mean circuit and QFG low-voltage fully-differential amplifiers with QFG common-mode feedback using several QIR structures. Measurements on current-mode QFG circuits exhibit large offsets and very long turn-on transients, which could limit practical application of this technique.

Comparison of Quasi-/Pseudo-Floating Gate Techniques and Low-Voltage Applications

Recently, the quasi- or pseudo-floating gate (QFG) technique has been suggested by several authors to implement many of the functions of the widely used floating-gate MOS transistors technique by using ultra-high resistances to isolate a floating node. Several different ways have been suggested to implement these quasi-infinite resistors (QIRs). In this paper, several basic QIR structure are analyzed and compared, and three sources of error, dc offset, signal distortion, and signal-dependent offset, are defined. Then, through simulations and experiments, the suitability of several QIR implementations for use in various applications is compared. One implementation is shown to minimize dc offset, but voltage swing is limited to less than 0.7 V/sub pp/. Configurations using parallel connections of QIRs improve signal distortion and signal-dependent offset, but still suffer from dc offset and limited voltage swing. Series-connected QIR structures allow increased voltage swings, but typically lead to hard-to-predict offsets of up to few hundred mV because of well-substrate leakage currents. Other circuits are also analyzed.

Comparison of quasi-/pseudo-floating gate techniques

A digital to analog converter (DAC) includes an operational amplifier and a plurality of ladder elements. Each ladder element includes an epot for providing a voltage, a capacitor, and a switch for selecting between a first voltage and a reference voltage, and for providing the first selected voltage to the first capacitor. The output of the ladder elements are coupled to the inverting input of the operational amplifier. Alternatively, the ladder elements may use tunable floating-gate resistors.

Programmable voltage-output floating-gate digital to analog converter and tunable resistors

We present a low-voltage/low power second order filter. The filter consists of 6 pseudo floating-gate transistors operated in weak inversion. The filter is suitable for any kind of application requiring low frequency ranges, such as biomedical products. An electronic cochlea consisting of replicas of the filter is presented. The filter operates at a supply voltage below 1 V, consumes power down to 5 nW, and has a harmonic distortion suppression of -60 dB.

A low voltage second order biquad using pseudo floating-gate transistors

A novel single transistor MOSFET circuit equivalent for a resistor is presented. The resistor value is tunable over six orders of magnitude. By exploring short channel effects a linear range of more than 2.5 V with <1% relative error is verified by simulation.

Resistive equivalents in CMOS

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

E.A. Olsen

Author Tools

Chat about Author

Papers

A low voltage second order biquad using pseudo floating-gate transistors

Resistive equivalents in CMOS