scholarly journals Fully integrated high quality factor <i>G</i><sub>m</sub><i>C</i> bandpass filter stage with highly linear operational transconductance amplifier

2017 ◽  
Vol 15 ◽  
pp. 149-155 ◽  
Author(s):  
Jochen Briem ◽  
Marco Mader ◽  
Daniel Reiter ◽  
Raul Amirpour ◽  
Markus Grözing ◽  
...  
Keyword(s):  
Bandpass Filter ◽  
Process Variations ◽  
Q Factor ◽  
Operational Transconductance Amplifier ◽  
High Quality ◽  
Fully Integrated ◽  
Local Process ◽  
Transconductance Amplifier ◽  
Control Circuits ◽  
Global And Local

Abstract. This paper presents an electrical, fully integrated, high quality (Q) factor GmC bandpass filter (BPF) stage for a wireless 27 MHz direct conversion receiver for a bendable sensor system-in-foil (Briem et al., 2016). The core of the BPF with a Q factor of more than 200 is an operational transconductance amplifier (OTA) with a high linearity at an input range of up to 300 mVpp, diff. The OTA's signal-to-noise-and-distortion-ratio (SNDR) of more than 80 dB in the mentioned range is achieved by stabilizing its transconductance Gm with a respective feedback loop and a source degeneration resistors RDG. The filter stage can be tuned and is tolerant to global and local process variations due to offset and common-mode feedback (CMFB) control circuits. The results are determined by periodic steady state (PSS) simulations at more than 200 global and local process variation parameter and temperature points and corner simulations. It is expected, that the parasitic elements of the layout have no significant influence on the filter behaviour. The current consumption of the whole filter stage is less than 600 µA.

scholarly journals Programmable CF-OTA-Based Lowpass and Bandpass Filters

1995 ◽  
Vol 18 (4) ◽  
pp. 267-272
Author(s):  
Muhammad Taher Abuelma'atti ◽  
Azhar Quddus
Keyword(s):  
Low Temperature ◽  
Input Impedance ◽  
Bandpass Filter ◽  
Attractive Feature ◽  
Operational Transconductance Amplifier ◽  
High Input ◽  
High Input Impedance ◽  
Transconductance Amplifier ◽  
Current Follower ◽  
Simulation Results

A new circuit is proposed for realizing lowpass and bandpass filter responses. The circuit uses one current-follower and one operational transconductance amplifier. The circuit enjoys low temperature sensitivities, high input impedance and its important parameters are electronically programmable. The use of grounded capacitors is an additional attractive feature for integration. Simulation results confirming the theory presented are included.

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

2021 ◽  
Vol 16 (2) ◽  
pp. 1-11
Author(s):  
Rafael Sanchotene Silva ◽  
Luís Henrique Rodovalho ◽  
Jefferson Luiz Brum Marques ◽  
Cesar Ramos Rodrigues
Keyword(s):  
Average Power ◽  
Signal Acquisition ◽  
Operational Transconductance Amplifier ◽  
Worst Case ◽  
Fully Integrated ◽  
Transconductance Amplifier ◽  
Narrow Bandwidth ◽  
Average Power Consumption ◽  
Long Time ◽  
Electrophysiological Signal

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.

scholarly journals An Automatic Offset Calibration Method for Differential Charge-Based Capacitance Measurement

2021 ◽  
Vol 11 (2) ◽  
pp. 22
Author(s):  
Umberto Ferlito ◽  
Alfio Dario Grasso ◽  
Michele Vaiana ◽  
Giuseppe Bruno
Keyword(s):  
Standard Deviation ◽  
Output Voltage ◽  
Process Variations ◽  
Calibration Method ◽  
Capacitance Measurement ◽  
Effective Technique ◽  
Fully Integrated ◽  
Front End ◽  
Novel Method ◽  
On Chip

Charge-Based Capacitance Measurement (CBCM) technique is a simple but effective technique for measuring capacitance values down to the attofarad level. However, when adopted for fully on-chip implementation, this technique suffers output offset caused by mismatches and process variations. This paper introduces a novel method that compensates the offset of a fully integrated differential CBCM electronic front-end. After a detailed theoretical analysis of the differential CBCM topology, we present and discuss a modified architecture that compensates mismatches and increases robustness against mismatches and process variations. The proposed circuit has been simulated using a standard 130-nm technology and shows a sensitivity of 1.3 mV/aF and a 20× reduction of the standard deviation of the differential output voltage as compared to the traditional solution.

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