scholarly journals A Sub-mW 18-MHz MEMS Oscillator Based on a 98-dBΩ Adjustable Bandwidth Transimpedance Amplifier and a Lamé-Mode Resonator

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2680
Author(s):  
Anoir Bouchami ◽  
Mohannad Y. Elsayed ◽  
Frederic Nabki

This paper presents a microelectromechanical system (MEMS)-based oscillator based on a Lamé-mode capacitive micromachined resonator and a fully differential high-gain transimpedance amplifier (TIA). The proposed TIA is designed using TSMC 65 nm CMOS technology and consumes only 0.9 mA from a 1-V supply. The measured mid-band transimpedance gain is 98 dB Ω and the TIA features an adjustable bandwidth with a maximum bandwidth of 142 MHz for a parasitic capacitance C P of 4 pF. The measured input-referred current noise of the TIA at mid-band is below 15 pA/ Hz . The TIA is connected to a Lamé-mode resonator, and the oscillator performance in terms of phase noise and frequency stability is presented. The measured phase noise under vacuum is −120 dBc/Hz at a 1-kHz offset, while the phase noise floor reaches −127 dBc/Hz. The measured short-term stability of the MEMS-based oscillator is ±0.25 ppm.

2013 ◽  
Vol 6 (2) ◽  
pp. 109-113 ◽  
Author(s):  
Andrea Malignaggi ◽  
Amin Hamidian ◽  
Georg Boeck

The present paper presents a fully differential 60 GHz four stages low-noise amplifier for wireless applications. The amplifier has been optimized for low-noise, high-gain, and low-power consumption, and implemented in a 90 nm low-power CMOS technology. Matching and common-mode rejection networks have been realized using shielded coplanar transmission lines. The amplifier achieves a peak small-signal gain of 21.3 dB and an average noise figure of 5.4 dB along with power consumption of 30 mW and occupying only 0.38 mm2pads included. The detailed design procedure and the achieved measurement results are presented in this work.


Author(s):  
Guillermo Royo ◽  
Carlos Sánchez-Azqueta ◽  
Concepción Aldea ◽  
Santiago Celma

In this work, we present a fully differential transimpedance amplifier (TIA) with controllable transimpedance for use in RF overlay downstream communication systems. The transimpedance amplifier has been designed in a standard 180-nm CMOS technology and it is intended for 47 MHz to 870 MHz subcarrier multiplexed RF signals. It performs a 18 dBΩ transimpedance gain control range for extended optical input range from -6 dBm up to +2 dBm.


2019 ◽  
Vol 8 (4) ◽  
pp. 1802-1808

The Front end read out circuits are major block in the implementation of Capacitive MEMS accelerometer. Front end read-out circuits comprises of preamplifier block containing folded cascode fully differential operational amplifier which are required for the signal conditioning of the signals received from the MEMS sensors. The op-amps are prime elements in design and implementation of mixed signal integrated circuits. The high gain and low power of the designed circuits helps in the designing of high precision IC’s for numerous application. Amongst the available topologies folded cascode topology plays vital role in the design and development of low power, high gain read out circuits. This paper illustrates the design and analysis of low power, high gain fully differential Folded Cascode Operational Amplifier for front end read out circuits. The designed op-amp exhibits a power consumption or dissipation of 92.14 μW and relatively higher open loop DC gain value with a value calculated at 81.33 dB by employing folded cascode topology. The UGB and Phase Margin for the selected design are 35 MHz and 83.60 respectively. The design operates at 5V power supply with the bias current of 12.11 μA. The circuit design and simulations have been implemented using 0.18 μm CMOS technology.


Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 188
Author(s):  
Žiga Korošak ◽  
Nejc Suhadolnik ◽  
Anton Pleteršek

The aim of this work is to tackle the problem of modulation wave shaping in the field of near field communication (NFC) radio frequency identification (RFID). For this purpose, a high-efficiency transmitter circuit was developed to comply with the strict requirements of the newest EMVCo and NFC Forum specifications for pulse shapes. The proposed circuit uses an outphasing modulator that is based on a digital-to-time converter (DTC). The DTC based outphasing modulator supports amplitude shift keying (ASK) modulation, operates at four times the 13.56 MHz carrier frequency and is made fully differential in order to remove the parasitic phase modulation components. The accompanying transmitter logic includes lookup tables with programmable modulation pulse wave shapes. The modulator solution uses a 64-cell tapped current controlled fully differential delay locked loop (DLL), which produces a 360° delay at 54.24 MHz, and a glitch-free multiplexor to select the individual taps. The outphased output from the modulator is mixed to create an RF pulse width modulated (PWM) output, which drives the antenna. Additionally, this implementation is fully compatible with D-class amplifiers enabling high efficiency. A test circuit of the proposed differential multi-standard reader’s transmitter was simulated in 40 nm CMOS technology. Stricter pulse shape requirements were easily satisfied, while achieving an output linearity of 0.2 bits and maximum power consumption under 7.5 mW.


Micromachines ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 82
Author(s):  
Rafel Perelló-Roig ◽  
Jaume Verd ◽  
Sebastià Bota ◽  
Jaume Segura

CMOS-MEMS resonators have become a promising solution thanks to their miniaturization and on-chip integration capabilities. However, using a CMOS technology to fabricate microelectromechanical system (MEMS) devices limits the electromechanical performance otherwise achieved by specific technologies, requiring a challenging readout circuitry. This paper presents a transimpedance amplifier (TIA) fabricated using a commercial 0.35-µm CMOS technology specifically oriented to drive and sense monolithically integrated CMOS-MEMS resonators up to 50 MHz with a tunable transimpedance gain ranging from 112 dB to 121 dB. The output voltage noise is as low as 225 nV/Hz1/2—input-referred current noise of 192 fA/Hz1/2—at 10 MHz, and the power consumption is kept below 1-mW. In addition, the TIA amplifier exhibits an open-loop gain independent of the parasitic input capacitance—mostly associated with the MEMS layout—representing an advantage in MEMS testing compared to other alternatives such as Pierce oscillator schemes. The work presented includes the characterization of three types of MEMS resonators that have been fabricated and experimentally characterized both in open-loop and self-sustained configurations using the integrated TIA amplifier. The experimental characterization includes an accurate extraction of the electromechanical parameters for the three fabricated structures that enables an accurate MEMS-CMOS circuitry co-design.


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