Pressure sensor chip utilizing electrical circuit of piezosensitive differential amplifier with negative feedback loop (PDA-NFL) for 5 kPa

High sensitive (S = 11.2 ± 1.8 mV/V/kPa with nonlinearity error 2KNL = 0.15 ± 0.09%/FS) small-sized (4.00x4.00 mm2) silicon pressure sensor chip utilizing new electrical circuit for microelectromechanical systems (MEMS) in the form of differential amplifier with negative feedback loop (PDA-NFL) for 5 kPa differential was developed. The advantages are demonstrated in the array of output characteristics, which prove the relevance of the presented development, relative to modern developments of pressure sensors with Wheatstone bridge electrical circuit for 5 kPa range.

Comparative Analysis of CNTFET Models through the Design of a Differential Amplifier

In this paper we compare simulation results on a differential pair circuit using a CNTFET model, already proposed by us, with the result obtained using Stanford model. We study the case of differential pair with differential input and single ended output as core of a 50 GHz amplifier for mm waves band. We consider the case of a CNTFET having a single CNT tube with indices (19,0) and 25 nm long. For this circuit we present result for its main parameters: gain, input impedance, output impedance, noise and distortion. Since the Stanford model includes fixed capacitance, for comparison we applied the same capacitance on our model. Since this capacitances dominate the high frequency cut, results are not much different, except for the lack of noise modelling in the Stanford model.

Investigation of sensitive element for pressure sensor based on bipolar piezotransistor

The article translated from Russian to English on pp. 691-693 (please, look down). The paper summarizes results of investigation of high-sensitivity MEMS pressure sensor based on a circuit containing both active and passive stress-sensitive elements: a differential amplifier utilizing two n-p-n piezotransistors and for p-type piezoresistors. A comparative analysis of a sensor utilizing this circuit with a pressure sensor based on traditional piezoresistive Wheatstone bridge and built on the same mechanical part is provided. MEMS pressure sensor with the differential amplifier (PSDA) has sensitivity of S = 0.66 mV/kPa/V, which exceeded the sensitivity of the element with piezoresistive Wheatstone bridge (PSWB) by 2.2 times. The sensitivity increase allows for the following sensor improvements: die size reduction, increase of diaphragm mechanical strength while keeping high pressure sensitivity, and simplifying requirements to external processing of the pressure sensor output signal. There are two main challenges related to the use of PSDA-based pressure sensors: strong dependence of output signal on temperature and higher than in PSWB noise reducing the dynamic range of the device to 10 3. The article describes methods of addressing these problems. The temperature dependence of sensor output signal can be minimized with help of an offset thermal compensation circuit and by eliminating metallization at the thin part of the diaphragm. The noise can be minimized by reducing the thickness of the active base region of the transistor. Circuit analysis with software NI Multisim shows that sensitivity of PSDA-based pressure sensor can be increased 2.3 times by circuit optimization.

Modeling of sensitive element for pressure sensor based on bipolar piezotransistor

The paper describes modeling of high-sensitivity MEMS pressure sensor based on a circuit containing both active and passive stress-sensitive elements: a differential amplifier utilizing two n-p-n transistors and four p-type piezoresistors. The analysis on the basis of the developed mathematical model for a pressure sensor with traditional piezoresistive Wheatstone bridge and theoretical conclusions regarding the change in the electrical parameters of a bipolar transistor under the influence of deformation was carried out.

Design of Two-Stage Differential Amplifier with Stacked Transistors for Biomedical Applications

In this paper, CMOS based optimized two stage differential amplifier circuit for convenient biomedical signal conditioning system is presented. A low-power, low noise & high CMRR differential amplifier is designed for portable ECG signal conditioning using MOS based low pass filter with stacked transistors. The stack transistors with MOS which is connected at output terminal optimize the design for ECG signal conditioning and other biomedical device signal conditioning. The presented amplifier is designed with standard 45nm CMOS process technology at a 0.85 V supply voltage. The simulation results are derived using Cadence Analog Virtuoso Spectre Simulator. The simulation results show that the presented differential amplifier has a common-mode rejection ratio (CMRR) of 178dB at 100Hz, power supply rejection ratio (PSRR) of 68 dB and power dissipation of 1.5μW. The input referred (IR) noise is 3.83μV/√f and slew rate is 11volt/μsec. These obtained performance parameters is better and efficient compared to conventional differential amplifier. The noise performance is improved using proposed design compared to previous designed differential amplifier.