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Fabian Khateb

Brno University of Technology, Department of Microelectronics, Faculty Member

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Papers by Fabian Khateb

0.5 V Current-Mode Low-Pass Filter Based on Voltage Second Generation Current Conveyor for Bio-Sensor Applications

IEEE Access

This paper presents a low-voltage low-power current-mode third-order low-pass filter (LPF) based ... more This paper presents a low-voltage low-power current-mode third-order low-pass filter (LPF) based on voltage second generation current conveyor (VCII). The VCII utilizes the bulk-driven MOS transistor technique to achieve a wide input voltage range at low supply voltage of 0.5 V. Also, the VCII operates in the subthreshold region to achieve nano-power consumption of 390 nW. A third-order low-pass filter that is presented as an application of the VCII can operate as both current-and transimpedance-mode filters. The filter consumes 2.73 µW and the total harmonic distortion (THD) is below 1 % for sine-wave input signal below 350 nA pp @ 10 Hz. The post-layout simulation results based on TSMC 0.18 µm CMOS process are presented and confirms the futures of the filter. INDEX TERMS Voltage second generation current conveyor, third-order low-pass filter, current-mode filter, low-voltage low-power, analog circuit.

1.2 V Differential Difference Transconductance Amplifier and Its Application in Mixed-Mode Universal Filter

Sensors

This paper presents a new mixed-mode universal filter based on a differential difference transcon... more This paper presents a new mixed-mode universal filter based on a differential difference transconductance amplifier (DDTA). Unlike the conventional transconductance amplifier (TA), this DDTA has both advantages of the TA and the differential difference amplifier (DDA). The proposed filter can offer four-mode operations of second-order transfer functions into a single topology, namely, voltage-mode (VM), current-mode (CM), transadmittance-mode (TAM), and transimpedance-mode (TIM) transfer functions. Each operation mode offers five standard filtering responses; therefore, at least twenty filtering transfer functions can be obtained. For the filtering transfer functions, the matching conditions for the input and passive component are absent. The natural frequency and the quality factor can be set orthogonally and electronically controlled. The performance of the proposed topology was evaluated by PSPICE simulator using the 0.18 µm CMOS technology from the Taiwan Semiconductor Manufactu...

format_quoteThe mixed-mode universal filter realizes four modes, yielding at least twenty filtering responses via DDTA design.format_quote

0.5 V Differential Difference Transconductance Amplifier and Its Application in Voltage-Mode Universal Filter

IEEE Access

This paper presents an innovative CMOS structure for Differential Difference Transconductance Amp... more This paper presents an innovative CMOS structure for Differential Difference Transconductance Amplifiers (DDTA). While the circuit operates under extremely low voltage supply 0.5 V, the circuit's performance is improved thanks to using the multiple-input MOS transistor (MI-MOST), the bulk-driven, self-cascode and partial positive feedback (PPF) techniques. As a result, the DDTA structure is less complex, with high gain of 93 dB, wide input voltage range nearly rail-to-rail, and wide transconductance tunability. As an example of application, a second-order voltage-mode universal filter using three DDTAs and two 6 pF integrated capacitors is presented. The filter is designed such that no matching conditions are required for the input and passive components, and the input signals need not be inverted. The natural frequency and the quality factor can be set orthogonally while the natural frequency can be electronically controlled. The circuit was designed and simulated in Cadence environment using 0.18 µm TSMC technology. The simulation results including intensive Monte-Carlo (MC) and process, temperature, voltage (PVT) analysis confirm the stability and the robustness of the design to process, mismatch variation and PVT corners.

0.3-Volt Rail-to-Rail DDTA and Its Application in a Universal Filter and Quadrature Oscillator

Sensors, 2022

This paper presents the extremely low-voltage supply of the CMOS structure of a differential diff... more This paper presents the extremely low-voltage supply of the CMOS structure of a differential difference transconductance amplifier (DDTA). With a 0.3-volt supply voltage, the circuit offers rail-to-rail operational capability. The circuit is designed for low-frequency biomedical and sensor applications, and it consumes 357.4 nW of power. Based on two DDTAs and two grounded capacitors, a voltage-mode universal filter and quadrature oscillator are presented as applications. The universal filter possesses high-input impedance and electronic tuning ability of the natural frequency in the range of tens up to hundreds of Hz. The total harmonic distortion (THD) for the band-pass filter was 0.5% for 100 mVpp @ 84.47 Hz input voltage. The slight modification of the filter yields a quadrature oscillator. The condition and the frequency of oscillation are orthogonally controllable. The frequency of oscillation can also be controlled electronically. The THD for a 67 Hz oscillation frequency was...

A 0.3-V High Linear Rail-to-Rail Bulk-Driven OTA in 0.13 μm CMOS

IEEE Transactions on Circuits and Systems II: Express Briefs, 2022

A 0.5-V 95-dB rail-to-rail DDA for biosignal processing

AEU - International Journal of Electronics and Communications, 2021

Nanopower multiple-input DTMOS OTA and its applications to high-order filters for biomedical systems

AEU - International Journal of Electronics and Communications, 2021

Abstract A new solution for a low-voltage multiple-input dynamic threshold operational transcondu... more Abstract A new solution for a low-voltage multiple-input dynamic threshold operational transconductance amplifier (MIDT OTA) for low-frequency signal processing applications is presented. The differential pairs of the proposed OTA combine, for the first time, the multiple-input MOS technique along with the dynamic threshold voltage MOS to achieve a very simple and power-efficient CMOS structure with increased total transconductance. Further, the proposed MIDT OTA has been used to realize a fifth-order low-pass filter (LP) and a sixth-order band-pass filter (BP) using coupled-biquads. The proposed OTA and the filter applications are supplied with 0.5 V and consume 5 nW and 25 nW, respectively. The input band pass filter noise is 82.76 µV, while the dynamic range is 59.5 dB for the third intermodulation distortion (IMD) of 2%. The proposed circuits were designed in a 0.18 µm TSMC technology, and validated by simulations using Cadence platform.

0.3-V Nanopower Biopotential Low-Pass Filter

IEEE Access, 2020

This paper presents a compact power-efficient CMOS fourth-order low-pass filter suitable for elec... more This paper presents a compact power-efficient CMOS fourth-order low-pass filter suitable for electrocardiogram (ECG) acquisition systems. The CMOS structure of the proposed filter utilize the bulkdriven technique and operates in subthreshold region to achieve extremely low-voltage supply (0.3V) and nanopower consumption (0.676 nW) for cutoff frequency of 100 Hz. The filter was designed and simulated using 0.18 µm CMOS TSMC technology. The total input referred noise of the filter is 87 µVrms and the dynamic range is 58.1 dB. The filter offers the best figure of merit of 2.91 × 10 −14 J, the lowest power consumption and voltage supply, compared with the previous state-of-the-art nanowatt filter designs. INDEX TERMS Biopotential filter, bulk-driven, low voltage, low power.

format_quoteThis paper introduces a CMOS filter operating at 0.3V and 0.676 nW, targeting ultra-low-power ECG systems with minimal noise.format_quote

0.5 V Fully Differential Universal Filter Based on Multiple Input OTAs

IEEE Access, 2020

The design of a low-power, low-voltage, fully-differential universal biquad filter is presented i... more The design of a low-power, low-voltage, fully-differential universal biquad filter is presented in this work, which is constructed from four multiple-input gate-driven operational transconductance amplifiers (MI-OTAs) along with one passive resistor and two passive capacitors. The scheme of presented biquad filter has three high-input impedance voltage nodes and single output voltage node. Five unity gain filtering functions, all-pass (AP), low-pass (LP), band-pass (BP), high-pass (HP) and band-stop (BS) responses, are obtained. The selection of output filtering responses is obtained without the need of component matching condition, inverting or double input voltage. With this feature, it can be easily controlled with digital programming. The quality factor (Q) and angular frequency (ω 0) are electronically and independently tuned. Moreover, the adjustment of ω 0 and Q can be done without affecting the voltage gain. A workability of the design is confirmed via Cadence software and the Spectre simulator based on the 180 nm TSMC CMOS technology parameters. The proposed fully differential filter operates with 0.5 V supply voltage. The results verify that the proposed filter dissipates the total power of 53.3 nW. Additionally, the dynamic range (DR) of band-pass filtering function is 63 dB for 2% third intermodulation distortion (IMD). Also, the simulated RMS value of the band-pass filtering noise is 45 µV. INDEX TERMS MI-OTA, low-power low-voltage circuit, universal filter, analog circuit, electronic control.

Charged Controlled Mem-Element Emulator and Its Application in a Chaotic System

IEEE Access, 2020

This article proposes a charged controlled emulator model for memristor and memcapacitor using se... more This article proposes a charged controlled emulator model for memristor and memcapacitor using second-generation Current Conveyor (CCIIs) and Analog Multiplier (AM). The grounded and floating mem-element circuits have been designed using two CCIIs and one multiplier in addition to some passive components. The grounded type of design requires three resistors and three capacitors while floating design necessitates only two resistors and two capacitors. With the help of a switch, the proposed design can be easily switched into a memristor or memcapacitor. The proposed emulator model has been theoretically analyzed and simulated in PSpice to substantiate the effectiveness and accuracy. The practicability of the circuit has been established using commercially available ICs AD844AN and AD633JN. Non-linear characteristics of the proposed memristor emulator have been used to design a chaotic system. INDEX TERMS Memristor, memcapacitor, pinched hysteresis loop, Chua's circuit.

ECCCII-Based Current-Mode Universal Filter with Orthogonal Control of w_o and Q

This paper presents a new current-mode cur- rent-controlled four-input five-output universal filt... more This paper presents a new current-mode cur- rent-controlled four-input five-output universal filter em- ploying one current-controlled current conveyor (CCCII), one electronically tunable CCCII and two grounded ca- pacitors. The proposed configuration provides lowpass, bandpass, highpass, bandstop and allpass current re- sponses that taken from the high-output impedance termi- nals, which enable easy cascadability of the current-mode operation. The filter also offers both orthogonal and elec- tronic controls of the natural frequency and the quality factor through adjusting the bias current of the CCCIIs. For realizing all the filter responses, the proposed filter does not require passive component-matching condition and both active and passive sensitivities are low. In addi- tion, a new current-mode current-controlled single-input five-output universal filter can be achieved by using an additional multiple-output minus-type CCCII. The proposed filter is simulated using PSPICE simula...

Inductance Simulators and Their Application to the 4th Order Elliptic Lowpass Ladder Filter Using CMOS VD-DIBAs

Electronics, 2021

This paper presents inductance simulators using the voltage differencing differential input buffe... more This paper presents inductance simulators using the voltage differencing differential input buffered amplifier (VD-DIBA) as an active building block. Three types of inductance simulators, including floating lossless inductance, series inductance-resistance, and parallel inductance-resistance simulators, are proposed, in addition to their application to the 4th order elliptic lowpass ladder filter. The simple design procedures of these inductance simulators using a circuit block diagram are also given. The proposed inductance simulators employ two VD-DIBAs and two passive elements. The complementary metal oxide semiconductor (CMOS) VD-DIBA used in this design utilizes the multiple-input metal oxide semiconductor (MOS) transistor technique in order to achieve a compact and simple structure with a minimum count of transistors. Thanks to this technique, the VD-DIBA offers high performances compared to the other CMOS structures presented in the literature. The CMOS VD-DIBAs and their app...

0.5 V Fifth-Order Butterworth Low-Pass Filter Using Multiple-Input OTA for ECG Applications

Sensors, 2020

This paper presents a 0.5 V fifth-order Butterworth low-pass filter based on multiple-input opera... more This paper presents a 0.5 V fifth-order Butterworth low-pass filter based on multiple-input operational transconductance amplifiers (OTA). The filter is designed for electrocardiogram (ECG) acquisition systems and operates in the subthreshold region with nano-watt power consumption. The used multiple-input technique simplifies the overall structure of the OTA and reduces the number of active elements needed to realize the filter. The filter was designed and simulated in the Cadence environment using a 0.18 µm Complementary Metal Oxide Semiconductor (CMOS) process from Taiwan Semiconductor Manufacturing Company (TSMC). Simulation results show that the filter has a bandwidth of 250 Hz, a power consumption of 34.65 nW, a dynamic range of 63.24 dB, attaining a figure-of-merit of 0.0191 pJ. The corner (process, voltage, temperature: PVT) and Monte Carlo (MC) analyses are included to prove the robustness of the filter.

Universal Filter Based on Compact CMOS Structure of VDDDA

Sensors, 2021

This paper proposes the simulated and experimental results of a universal filter using the voltag... more This paper proposes the simulated and experimental results of a universal filter using the voltage differencing differential difference amplifier (VDDDA). Unlike the previous complementary metal oxide semiconductor (CMOS) structures of VDDDA that is present in the literature, the present one is compact and simple, owing to the employment of the multiple-input metal oxide semiconductor (MOS) transistor technique. The presented filter employs two VDDDAs, one resistor and two grounded capacitors, and it offers low-pass: LP, band-pass: BP, band-reject: BR, high-pass: HP and all-pass: AP responses with a unity passband voltage gain. The proposed universal voltage mode filter has high input impedances and low output impedance. The natural frequency and bandwidth are orthogonally controlled by using separated transconductance without affecting the passband voltage gain. For a BP filter, the root mean square (RMS) of the equivalent output noise is 46 µV, and the third intermodulation distor...

format_quoteThis work introduces a design method for universal biquad filters, enabling orthogonal tuning of quality factor and natural frequency.format_quote

0.5-V High Linear and Wide Tunable OTA for Biomedical Applications

IEEE Access, 2021

This paper presents a low-voltage nano-power multiple-input operational transconductance amplifie... more This paper presents a low-voltage nano-power multiple-input operational transconductance amplifier (MI-OTA) with high linearity performance and increased input voltage swing. The enhanced performances are achieved thanks to employing several techniques as the bulk-driven, source-degeneration, self-cascode and negative conductance along with the concept of the input signal attenuation formed by multiple-input MOS transistor. The MI-OTA is widely tunable that serves for biological signals processing. A 3 rd-order Butterworth band-pass filter (BPF) for electrocardiogram (ECG) signal processing with 55.8 dB dynamic rang is presented. The MI-OTA circuit is designed for 0.5V voltage supply and offers a 0.22% total harmonic distortion (THD) for 0.2V pp input signal with total power consumption of 13.4nW. Extensive simulation results including Monte Carlo analysis and process, voltage, temperature (PVT) corners using the 0.18µm CMOS technology from TSMC confirm the characteristics of the proposed MI-OTA and the filter. INDEX TERMS Operational transconductance amplifier (OTA), bulk-driven MOS transistor, multiple-input OTA, high-order filters.

Mem-Elements Emulator Design With Experimental Validation and Its Application

IEEE Access, 2021

An emulator circuit of Memristor, Memcapacitor, and Meminductor commonly termed as mem-elements h... more An emulator circuit of Memristor, Memcapacitor, and Meminductor commonly termed as mem-elements has been demonstrated in this article. The circuit has been realized using the technique of current mode, which provides better performance over voltage mode counterparts. The current mode analog building blocks, along with a few passive components, have been used in the presented circuit implementation. The fingerprint characteristics have been observed in both simulation and experimental results, validating the theoretical analysis. The robustness of the presented design has been supported by performing different types of analysis like process corner, temperature, and non-volatility behavior. The mem-elements emulator design has been simulated using 0.18 µm TSMC process parameter, and ±1.2 V power supply has been used. The commercial ICs AD844 and CA3080 are used for the experimental demonstration of the proposed mem-elements design by making a prototype on a breadboard. A layout area of 4829 µm 2 , 8098 µm 2 , and 8061 µm 2 respectively is required for the Memristor, Memcapacitor, and meminductor circuit. The power consumed by the mem-elements circuit is also provided. A chaotic has been implemented using mem-elements to show the usefulness of the emulator design.

0.5 V sixth-order Chebyshev band-pass filter based on multiple-input bulk-driven OTA

AEU - International Journal of Electronics and Communications, 2019

This paper presents a low-voltage sixth-order Chebyshev band-pass filter based on multiple-input ... more This paper presents a low-voltage sixth-order Chebyshev band-pass filter based on multiple-input operational transconductance amplifier (MI-OTA). The used voltage supply is 0.5 V and the filter employs six MI-OTAs and six capacitors. The third intermodulation distortion (3rd IMD) is below 1% for input sine wave signal with peak-to-peak up to rail-to-rail while the dynamic range (DR) is 66.8 dB. In order to insure low-voltage operation capability, extended linear range, increased voltage gain of the MI-OTA, the multiple-input bulk-driven transistor (MIBD) along with self-cascode techniques have been used. As a result, the proposed MI-OTA based on MIBD is capable to work with 0.5 V supply voltage and consumes power in the range of (2.5-1.2E3) nW for tunable bias current in the range from 1 nA to 500 nA. The MI-OTA and the filter circuits were designed and simulated in Cadence/Spectre environment using 0.18 mm CMOS process from TSMC. The simulation results agree well with theory and confirm the filter functionality.

Four-Input One-Output Voltage-Mode Universal Filter Using Simple OTAs

Journal of Circuits, Systems and Computers, 2019

This paper presents a new electronically tunable voltage-mode universal filter with four-input on... more This paper presents a new electronically tunable voltage-mode universal filter with four-input one-output employing six simple operational transconductance amplifiers (OTAs), two grounded capacitors and two MOS resistors. The use of grounded passive components is beneficial for integrated circuit implementation. The proposed filter can realize low-pass, band-pass, high-pass, band-stop and all-pass filtering functions without active and passive component-matching conditions and inverting-type input signals requirements. The natural frequency and quality factor can be tuned independently and electronically by adjusting the bias currents. The voltage-mode filter offers the features of high-input impedance and low active and passive sensitivities. The characteristics of the proposed universal filter are verified using PSPICE simulators through 0.35[Formula: see text][Formula: see text]m CMOS process. Experimental results are used to confirm the workability of proposed circuit through LM...

Bulk-driven fully balanced second-generation current conveyor in 0.18 µm CMOS

AEU - International Journal of Electronics and Communications, 2019

This paper presents an ultra-low-voltage and low-power fully balanced second-generation current c... more This paper presents an ultra-low-voltage and low-power fully balanced second-generation current conveyor (FBCCII) which is suitable for applications in ultra-low-voltage and low-power analog circuits. To confirm the attractive features of proposed FBCCII, the analog circuits such as fully digital programmable voltage gain amplifier, fully all-pass sections, fully band-pass filter and fully universal filter using the proposed FBCCII as active element have been proposed. The performances of the proposed FBCCII and its applications can be depicted through simulation results using SPICE simulations and 0.18 mm n-well CMOS process from TSMC with a 0.5 V supply.

0.3-V Bulk-Driven Nanopower OTA-C Integrator in 0.18 µm CMOS

Circuits, Systems, and Signal Processing, 2018

This short paper presents the experimental results for a 0.3-V fully differential OTA-C integrato... more This short paper presents the experimental results for a 0.3-V fully differential OTA-C integrator, implemented in a standard n-well 0.18 µm CMOS technology from TSMC with chip area 350 × 100 µm. The integrator consists of an adaptively biased bulk-driven linear operational transconductance amplifier (OTA) and a low-distortion common-mode feedback circuit. The integrator can operate with supply voltages ranging from 0.3 to 0.5 V. For a 0.3-V version, its cutoff frequency can be tuned from 50 to 334 Hz for a 220 pF load capacitance. For a nominal biasing current, its power consumption is 50 nW and the dynamic range is 75 dB.