A fully integrated 0.5-7 Hz CMOS bandpass amplifier

Arnaud, Alfredo; Galup-Montoro, Carlos

doi:10.1109/iscas.2004.1328227

Cited by 13 publications

(4 citation statements)

References 14 publications

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“…It is interesting to note here that the integrated circuits from two different fabrication batches, reported in this study and in [16], have a center frequency and quality factor very close to the specified ones. If still required, an automatic or trimmable tuning scheme acting on the bias current of one or several OTAs to set the appropriate ω 0 and Q value is possible.…”

Section: Dispersion Analysis and Discussionsupporting

confidence: 66%

Fully integrated signal conditioning of an accelerometer for implantable pacemakers

Arnaud

Galup-Montoro

2006

Analog Integr Circ Sig Process

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This paper shows the development of a fully integrated G m -C 0.5-7 Hz bandpass amplifier (gain G = 400), for a piezoelectric accelerometer to be employed in rate adaptive pacemakers. The circuit, fabricated in a standard 0.8 micron CMOS technology, operates with a power supply as low as 2 V, consumes 230 nA of current, and has only a 2.1 µV rms input referred noise. Detailed circuit specifications, measurements, and a system performance comparative analysis are presented. The physical activity system includes a fully integrated G m -C rectifier and 3-second time average. Fully integrated very low frequency circuits were implemented with the aid of series-parallel current division in symmetrical OTAs. OTAs as low as 33 pS (equivalent to a 30 G resistor) were designed, fabricated, and tested.

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Section: Dispersion Analysis and Discussionsupporting

confidence: 66%

Fully integrated signal conditioning of an accelerometer for implantable pacemakers

Arnaud

Galup-Montoro

2006

Analog Integr Circ Sig Process

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“…Previous works on LVLP CMOS techniques for obtaining a very-low transconductance essentially combine different strategies such as voltage attenuation, source degeneration and current splitting [1][2][3][4]. The intrinsic input-voltage attenuating properties of floating-gate and bulk-driven techniques are exploited in [1].…”

Section: Introductionmentioning

confidence: 99%

“…Because the final current of around 400 pA is well above leakage current levels, a more predictable transconductance is obtained, at the expense of power consumption. Conversely, a smaller division factor of 784 and a lower bias current are defined in [4], reducing the final current to only a few pA, which implies a less accurate transconductance.…”

Section: Introductionmentioning

confidence: 99%

An ultra low power CMOS pA/V transconductor and its application to wavelet filters

Agostinho

Haddad

Lima³

et al. 2008

Analog Integr Circ Sig Process

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Two compact ultra low-power CMOS triode transconductor topologies denoted VLPT-g m and Delta-g m are proposed. In both circuits, input transistors are kept in the triode region to benefit from the lowest g m /I D ratio. This allows achieving a small-signal transconductance g m down to hundreds of pA/V, making such transconductors attractive for the synthesis of g m -C filters with cut-off frequencies in the range of Hz and sub-Hz. The g m value is adjusted by a well defined aspect-ratio (W/L) and drainsource voltage V DS , the latter a replica of the tuning voltage V TUNE imposed as drain-source voltage of input devices. VLPT-g m reaches a minimum g m of 1 nA/V, whereas Delta-g m exhibits a g m as low as 400 pA/V. Inputreferred noise spectral density is typically 12.33 lV/Hz 1/2 @ 1 Hz and 93.75 lV/Hz 1/2 @ 1 Hz for VLPT-g m and Delta-g m , respectively. In addition, setting their g m equal to 1 nA/V and arranging them as first-order lossy integrators, Delta-g m presents higher bandwidth with respect to VLPTg m . Cut-off frequencies are 1.33 kHz and 24 kHz for VLPT-g m and Delta-g m integrators, respectively. Finally, as an application example, both transconductors were used as building blocks to realize a 6th-order wavelet g m -C filter. For both approaches, THD was kept below 1% for signal swings up to 200 mV pp .The design complies with a 1.5 V supply and a 0.35 lm CMOS process and features an overall power consumption of 51 and 114 nW, respectively for VLPT-g m and Delta-g m filters.

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“…In the source-degeneration scheme presented in [2], a triodebiased transistor simply mimics a voltage-controlled resistor. Matching is a crucial problem in current splitting, since a large number of unitycell transistors compose the current mirrors to implement very high division factors [3,4].…”

mentioning

confidence: 99%

Compact nA/V triode-MOSFET transconductor

Lima¹,

Serdijn

2005

Electron. Lett.

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A simple nA=V CMOS transconductor for low-frequency g m-C filters is presented. To benefit from the lowest g m =I D ratio, input transistors operate in the triode region, with g m adjusted by their (W=L) and V DS , the latter a tuning-voltage replica. Since V DS surmounts the equivalent noise of the replica circuit, excellent control of g m is attained. Simulations support theoretical analysis. A 5Hz bandpass filter was designed, featuring SNR ¼ 59.2 dB for THD < 1% at 150 mV and 17 nW consumption.

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A fully integrated 0.5-7 Hz CMOS bandpass amplifier

Cited by 13 publications

References 14 publications

Fully integrated signal conditioning of an accelerometer for implantable pacemakers

Fully integrated signal conditioning of an accelerometer for implantable pacemakers

An ultra low power CMOS pA/V transconductor and its application to wavelet filters

Compact nA/V triode-MOSFET transconductor

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