A 2.6 ppm/°C 2.5 V Piece-Wise Compensated Bandgap Reference with Low Beta Bipolar

Traditional bandgap reference (BGR) is sensitive to process variation and is not suitable for mass production. Consequently, a stacked piece-wise compensated bandgap reference (SPWBGR) with low beta bipolar is proposed, designed and fabricated in the 0.18 μm high-voltage (HV) BCD process. Two stacked BGR (SBGR) cores make up the proposed BGR circuit. Through setting the target reference voltage near the output voltage of SBGR cores, the feedback resistor ratio is reduced and the base current side-effect is significantly decreased. Notably, the SBGR core is implemented by the low beta npn bipolar and it relaxes the requirement for the high beta bipolar. The two SBGR cores are almost identical except for the temperature slope and feedback ratio. The two cores have different zero temperature coefficient (TC) points, one is set at −5 °C, and the other is set at 60 °C, named as SBGRA and SBGRB, respectively. The SBGRA and SBGRB output the same voltage at their zero TC point. The higher voltage of SBGRA and SBGRB is the output voltage. Through the process of tracking the maximum value of different SBGR cores, the proposed SPWBGR achieves 2.6 ppm/°C TC from −40 to 100 °C. As a result, the average TC for five random samples is 5.3 ppm/°C. The line regulation is 2 mV/V from 4.5 to 5.5 V power supply. The current consumption is 6.8 µA. The active area of the proposed BGR is 0.075 mm2.

On the Performance of an Aerosol Electrometer with Enhanced Detection Limit

An aerosol electrometer with enhanced detection limit was developed for measuring the collected particles electrical current ranging from −50 pA to 50 pA with no range switching necessary. The detection limit was enhanced by suppressing the electric current measurement noise and improving the detection efficiency. A theoretical model for the aerosol electrometer has been established to investigate the noise effect factors and verified experimentally. The model showed that the noise was a function of ambient temperature, and it was affected by the characteristics of feedback resistor and operational amplifier simultaneously. The Faraday cup structure of the aerosol electrometer was optimized by adopting a newly designed cup-shaped metal filter which increased the surface area of the cup; thus the particle interception efficiency was improved. The aerosol electrometer performance-linearity, noise and the particle detection efficiency, were evaluated experimentally. When compared with TSI-3068B, a 99.4% ( R 2 ) statistical correlation was achieved. The results also showed that the root mean square noise and the peak-to-peak noise were 0.31 fA and 1.55 fA, respectively. The particle detection efficiency was greater than 99.3% when measuring particle diameter larger than 7.0 nm.

A Widely Tunable Bandpass CMOS Filter Based on a Low-Voltage Active Inductor

A Chebyshev bandpass filter for digital TV (DTV) tuner ICs, as an RF tracking filter, based on a low-voltage tunable active inductor (TAI) is presented. The new filter has a tuning range of 200–800[Formula: see text]MHz. Independent tuning of the inductance and central frequency of the filter are very important in this wide frequency span. Adjusting the inductance for tuning of the filter should not vary its quality factor and consequently performance of the filter. Use of a feedback resistor in the active inductor makes the inductance and quality factor tuning-independent. Moreover, the feedback resistor increases the quality factor of the active inductor. Biasing the bulk terminals of the devices to a positive voltage, we achieve low threshold devices and consequently low voltage TAI. The proposed filter has IIP3 and noise figure of [Formula: see text]0.8 to 9.5[Formula: see text]dBm and 19.1 to 20.9[Formula: see text]dB, respectively. Besides, the power consumption varies from 9.6 to 25.5[Formula: see text]mW in the tuning range of 200–800[Formula: see text]MHz.

Noise Analysis of Trans-impedance Amplifier (TIA) in Variety Op Amp for use in Visible Light Communication (VLC) System

VLC is a complex system with lots of challenges in its implementation. One of its problems is noise that originated from internal and external sources (sunlight, artificial light, etc). Internal noise is originated from active components of analog front-end (AFE) circuit, which will be discussed in this paper, especially on the trans-impedance amplifier (TIA) domain. The noise characteristics of AFE circuit in VLC system has been analyzed using the variety of available commercial Op Amp and different types of the photodiode (Si, Si-PIN, Si APD). The approach of this research is based on analytical calculus and simulation using MATLAB®. The results of this research show that the main factor that affecting the noise is en, the feedback resistor (Rf), and junction capacitor in the photodiode (Cj). Besides that, the design concept of multi channel TIA (8 channel) using IC Op Amp, with consideration of pin number of each Op Amp, supply needs, the initial value of Rf, converter to 8-DIP and feedback capacitor (Cf) channel, also discussed in this paper.