Bulk Linearization Techniques

Arnaud, Alfredo; Puyol, Rafael; Hardy, Denisse; Miguez, Matías; Gak, Joel

doi:10.1109/iscas.2019.8702327

Cited by 6 publications

(3 citation statements)

References 14 publications

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“…improves transistor matching, output conductance, and immunity against process variations (particularly to threshold voltages). It also increases the common-mode rejection ratio (CMRR), while it is reported to improve transconductance linearity [20,28,29]. The two types of series-parallel associations employed in this work (rectangular and trapezoidal) are detailed in Appendix -Transistors Associations.…”

Section: A Transconductance Reduction Through Current Subtractionmentioning

confidence: 99%

“…Input offset voltage and flicker noise are limited by the active area of input devices (M R5 and M R6 ). Considering a fixed biasing current, if the aspect ratio of input pair transistors is increased, the inversion level decreases, thus leading linearity to decrease [29]. For a very low inversion level, the transistor length and resulting area tend to be very large.…”

Section: A Transconductance Reduction Through Current Subtractionmentioning

confidence: 99%

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A 59 pA/V and 62 nW Differential OTA with 0.35% THD for Biomedical Applications

Silva

Rodovalho

Marques

et al. 2021

JICS

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This paper presents a novel differential pA/V Operational Transconductance Amplifier (OTA) topology. The circuit is suitable for the implementation of fully integrated operational transconductance amplifier-capacitance (OTA-C) filters with small feature size capacitors, suited for electrophysiological signal acquisition and conditioning. Unlike typical OTA-Cs, the proposed topology consists of transconductance reduction technique based on unbalanced output branches thatallow current subtraction thus enabling transconductances in the order of pA/V. The technique is demonstrated through the design of a 59pA/V transconductor, which is very suited for designing long-time-constant filters. This OTA-C achieved a worst-case 0.35% THD with just 61.7nW average power consumption, which allows its applicability to biomedical implants. Simulations were carried out with STMicroelectronics 0.13µm HCMOS9 node using Cadence’s IC design tools. Weemployed the OTA in a design of a fourth-order bandpass filter with a narrow bandwidth of 12.5–21.8Hz. Similar results to the ideal transfer function, turn the proposed OTA ideal for biosensing-based applications.

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Section: A Transconductance Reduction Through Current Subtractionmentioning

confidence: 99%

Section: A Transconductance Reduction Through Current Subtractionmentioning

confidence: 99%

A 59 pA/V and 62 nW Differential OTA with 0.35% THD for Biomedical Applications

Silva

Rodovalho

Marques

et al. 2021

JICS

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“…A schematic of the proposed G mRect precision rectifier is shown in Figure 3, based on a bulk-degenerated OTA. 15,16 The rectifier consists of a linearized differential pair with two different current mirrors copying the current to the output with a different sign; a second, nonlinearized symmetrical OTA G m2 actuating as comparator controls two NMOS switches to select which of the outputs I Out1 or I Out2 is the active one. The resulting output current is…”

Section: A 120-na Rectifier Transconductormentioning

confidence: 99%

Nano–power‐integrated precision rectifiers for implantable medical devices

Alvarez

Arnaud

Gak

et al. 2020

Circuit Theory & Apps

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Summary Two ultralow power CMOS full‐wave precision rectifiers aimed at analog signal processing in implantable medical devices are presented. The rectifiers require no diodes and utilize a single or two transconductors (operational transconductance amplifier [OTA]) as the active element, to reduce power consumption to a minimum. First, a voltage‐to‐current rectifier consuming only a 120‐nA supply current is presented and later is used to estimate the average AC amplitude of a piezoelectric accelerometer output (0.5–15‐Hz bandwidth) in an adaptive pacemaker. This rectifier is based on a linearized transconductor and a comparator to toggle the output current sign. Then, a novel voltage rectifier consuming less than 10 nA is presented based on a single nanopower OTA and a pass transistor and later is utilized in a pacemaker's cardiac sensing channel (60–200‐Hz bandwidth) circuit, incorporating the rectifier to detect positive and negative voltage signal spikes. Both rectifiers were designed in a 0.6‐μm CMOS technology, fabricated, and tested, and the measurement results closely fit the expected performance.

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