Low input impedance current differencing unit for current mode active devices improved by positive feedback and ZC-CDBA filter application

2013 ◽  
Author(s):  
Ersin Alaybeyoglu ◽  
Arda Guney ◽  
Mustafa Altun ◽  
Hakan Kuntman
Keyword(s):  
Positive Feedback ◽  
Input Impedance ◽  
Current Mode ◽  
Low Input ◽  
Active Devices

scholarly journals A Novel Current–Mode High–Frequency Polyphase Filter using Multi–Output Current Differencing Transconductance Amplifiers

2016 ◽  
Vol 67 (5) ◽  
pp. 311-322
Author(s):  
Hao Peng ◽  
Chunhua Wang ◽  
Xiaotong Tian
Keyword(s):  
Input Impedance ◽  
Current Mode ◽  
Output Impedance ◽  
Output Current ◽  
Polyphase Filter ◽  
Low Input ◽  
Centre Frequency ◽  
Transconductance Amplifiers ◽  
High Output Impedance ◽  
High Output

Abstract This paper introduces a novel polyphase filter working at high centre frequency using multi-output current differencing transconductance amplifiers (MOCDTAs). The MOCDTA possesses characteristics of low input impedance, high output impedance, wide work frequency and linearly adjustable transconductance. The proposed filter consists of two MOCDTAs, two grounded capacitors, and no resistors. The features of low input impedance and high output impedance make it suitable for cascade. The bandwidth and centre frequency could be adjusted independently by external bias voltage VC and VCa. The image rejection ratio (IRR) could reach 31.6 dB at the centre frequency of 114 MHz, and its bandwidth could be 11.1 MHz. Besides, the centre frequency could be tuned from 38 MHz to 150 MHz with bandwidth of 20.1 MHz. Simulation results which verify the theory are included.

Design and Analysis of a Broadband Current-Mode CMOS Direct-Conversion Receiver Frond-End Circuit

2019 ◽  
Vol 28 (10) ◽  
pp. 1950169
Author(s):  
Xin Han Chen ◽  
Shuxiang Song ◽  
Mingcan Cen
Keyword(s):  
Duty Cycle ◽  
Input Impedance ◽  
Noise Figure ◽  
Current Mode ◽  
Direct Conversion ◽  
Low Noise ◽  
Transimpedance Amplifier ◽  
Conversion Gain ◽  
Low Input ◽  
A Current

A broadband (0.8–5[Formula: see text]GHz) CMOS current-mode direct-conversion receiver has been integrated in a 0.18-[Formula: see text]m CMOS process. The proposed receiver front-end features a broadband active-balun low-noise transconductance amplifier (LNTA) driving a current-mode passive mixer terminated by a low-input-impedance transimpedance amplifier (TIA). The receiver chain has improved robustness to out-of-band interference, conversion gain and outstanding linearity. With the technique of noise and distortion cancellation which performs a better input impedance matching, we employ a broadband common-gate–common-source (CG–CS) LNTA and a current mirror to improve both gain and noise figure (NF) performance. Compared to the 50% duty-cycle switching stage, the 25% duty-cycle I–Q switching stage is implemented by using serial switches driven by 50% quadrature local oscillator (LO) signals separately, which improves the down-conversion gain by 3[Formula: see text]dB and lowers the noise figure. The transimpedance amplifier employs the [Formula: see text]-boosting technique to realize low input impedance and high transimpedance gain. The core circuit (RF and baseband signal path) consumes 26[Formula: see text]mW, and the prototype receiver achieves approximately 33–34.5-dB conversion gain, 8.1–9.35-dB NF and 7.5–9.8-dBm IIP3 from 0.8[Formula: see text]GHz to 5[Formula: see text]GHz.

An Ultra-High Input Impedance Analog Front End Using Self-Calibrated Positive Feedback

2018 ◽  
Vol 53 (8) ◽  
pp. 2252-2262 ◽  
Author(s):  
Jinseok Lee ◽  
Geon-Hwi Lee ◽  
Hyojun Kim ◽  
SeongHwan Cho
Keyword(s):  
Positive Feedback ◽  
Input Impedance ◽  
High Input ◽  
High Input Impedance ◽  
Front End ◽  
Analog Front End
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