Wide-linear-range subthreshold OTA for low-power, low-Voltage, and low-frequency applications

Mourabit, Aimad El; Lu, Guo‐Neng; Pittet, Patrick

doi:10.1109/tcsi.2005.852011

Cited by 50 publications

(28 citation statements)

References 15 publications

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“…Some involve directly adding or removing charge on the gate through tunneling, hot-electron injection, or ultraviolet exposure. Alternatively, MOS switches (switched-capacitor circuits) and ultrahigh resistance connections (the quasi-floating-gate technique) can be used to establish the gate voltage [10]. All these approaches add complexity and expense to the system.…”

Section: Effect Of the Component Mismatches On Linearitymentioning

confidence: 99%

“…All these approaches add complexity and expense to the system. However, it was pointed out in [10,11] that when poly gate layers are connected to isolated metal layers, but are otherwise floating (a connection referred to here as ''almost-floating''), nearzero initial gate charge is present. This is very useful, as it allows many circuits to be implemented without accounting for initial charge.…”

Section: Effect Of the Component Mismatches On Linearitymentioning

confidence: 99%

“…This is very useful, as it allows many circuits to be implemented without accounting for initial charge. Several circuits have been demonstrated using this approach [10,12].…”

Section: Effect Of the Component Mismatches On Linearitymentioning

confidence: 99%

See 2 more Smart Citations

An alternative to source degeneration of CMOS differential pair

Mourabit

Pittet

2009

Analog Integr Circ Sig Process

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This paper presents a method to extend linear range of conventional CMOS source-coupled pair with transistor polarised on saturation of strong inversion. The used principle is similar to the principle of source degeneration, but the additional device is horizontally added, in parallel with the input transistors, which overcame the constraints on common mode range and supply voltage and allow low voltage operation. SPICE simulations using 0.35 lm CMOS process and a bias current of 10 lA, show that for less than 1% of transconductance variation, the linear range is up to 0.35 V pp in comparison to 0.1 V pp for source-degenerated pair, and 0.01 V pp for conventional differential pair, under the same biasing current and geometrical dimensions.

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Section: Effect Of the Component Mismatches On Linearitymentioning

confidence: 99%

Section: Effect Of the Component Mismatches On Linearitymentioning

confidence: 99%

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An alternative to source degeneration of CMOS differential pair

Mourabit

Pittet

2009

Analog Integr Circ Sig Process

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“…Many linearity improvement techniques have been reported in recent years, such as attenuation [2], source degeneration [3][4][5], nonlinear terms cancelation [6][7][8][9][10][11], and triode-based transconductor [12][13][14]. The linearity can be improved by adding resistance in source of the input transistors in the source degeneration technique.…”

Section: Introductionmentioning

confidence: 99%

A 0.8‐V supply bulk‐driven operational transconductance amplifier and Gm‐C filter in 0.18 µm CMOS process

Abbasalizadeh

Sheikhaei

Forouzandeh

2014

Circuit Theory & Apps

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SUMMARYA low voltage bulk-driven operational transconductance amplifier (OTA) and its application to implement a tunable Gm-C filter are presented. The linearity of the proposed OTA is achieved by nonlinear terms cancelation technique, using two paralleled differential topologies with opposite signs in the third-order harmonic distortion term of the differential output current. The proposed OTA uses 0.8 V supply voltage and consumes 31.2 μW. The proposed OTA shows a total harmonic distortion of better than À40 dB over the tuning range of the transconductance, by applying 800 mV ppd sine wave input signal with 1 MHz frequency. The OTA has been used to implement a third-order low-pass Gm-C filter, which can be used for wireless sensor network applications. The filter can operate as the channel select filter and variable gain amplifier, simultaneously. The gain of the filter can be tuned from À1 to 23 dB, which results in power consumptions of 187.2 to 450.6 μW, respectively. The proposed OTA and filter have been simulated in a 0.18 μm CMOS technology. Simulations of process corners and temperature variations are also included in the paper.

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“…The reason is that weak inversion current in an MOS transistor depends exponentially on voltage. For approximately 1% of transconductance variation, a traditional symmetrical OTA built with a gate-driven differential pair in weak inversion has a linear input range of a few 10 mV [2]. Several modified symmetrical OTAs have been developed to achieve transconductances in the order of a few nA/V with a linear input range up to 1 V or more, where the natural attenuating properties of the floating-gate and bulk-driven transistors have been advantageously utilized for realizing small transconductance values [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

An ultra-low-power CMOS symmetrical OTA for low-frequency G m -C applications

Cotrim

Ferreira

2011

Analog Integr Circ Sig Process

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In this paper an ultra-low-power CMOS symmetrical operational transconductance amplifier (OTA) for low-frequency G m -C applications in weak inversion is presented. Its common mode input range and its linear input range can be made large using DC shifting and bulkdriven differential pair configuration (without using complex approaches). The symmetrical OTA was successfully verified in a standard CMOS 0.35-lm process. The measurements show an open loop gain of 61 dB and a unit gain frequency of 195 Hz with only 800 mV of power supply voltage and just 40 nW of power consumption. The transconductance is 66 nS, which is suitable for lowfrequency G m -C applications.

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Wide-linear-range subthreshold OTA for low-power, low-Voltage, and low-frequency applications

Cited by 50 publications

References 15 publications

An alternative to source degeneration of CMOS differential pair

An alternative to source degeneration of CMOS differential pair

A 0.8‐V supply bulk‐driven operational transconductance amplifier and Gm‐C filter in 0.18 µm CMOS process

An ultra-low-power CMOS symmetrical OTA for low-frequency G m -C applications

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