scholarly journals Ladder-Based Synthesis and Design of Low-Frequency Buffer-Based CMOS Filters

Electronics ◽  
2021 ◽  
Vol 10 (23) ◽  
pp. 2931
Author(s):  
Waldemar Jendernalik ◽  
Jacek Jakusz ◽  
Grzegorz Blakiewicz

Buffer-based CMOS filters are maximally simplified circuits containing as few transistors as possible. Their applications, among others, include nano to micro watt biomedical sensors that process physiological signals of frequencies from 0.01 Hz to about 3 kHz. The order of a buffer-based filter is not greater than two. Hence, to obtain higher-order filters, a cascade of second-order filters is constructed. In this paper, a more general method for buffer-based filter synthesis is developed and presented. The method uses RLC ladder prototypes to obtain filters of arbitrary orders. In addition, a set of novel circuit solutions with ultra-low voltage and power are proposed. The introduced circuits were synthesized and simulated using 180-nm CMOS technology of X-FAB. One of the designed circuits is a fourth-order, low-pass filter that features: 100-Hz passband, 0.4-V supply voltage, power consumption of less than 5 nW, and dynamic range above 60 dB. Moreover, the total capacitance of the proposed filter (31 pF) is 25% lower compared to the structure synthesized using a conventional cascade method (40 pF).

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1547
Author(s):  
Xiangyu Chen ◽  
Yasuhiro Takahashi

In this paper, a transimpedance amplifier (TIA) based on floating active inductors (FAI) is presented. Compared with conventional TIAs, the proposed TIA has the advantages of a wider bandwidth, lower power dissipation, and smaller chip area. The schematics and characteristics of the FAI circuit are explained. Moreover, the proposed TIA employs the combination of capacitive degeneration, the broadband matching network, and the regulated cascode input stage to enhance the bandwidth and gain. This turns the TIA design into a fifth-order low pass filter with Butterworth response. The TIA is implemented using 0.18 μ m Rohm CMOS technology and consumes only 10.7 mW with a supply voltage of 1.8 V. When used with a 150 fF photodiode capacitance, it exhibits the following characteristics: gain of 41 dB Ω and −3 dB frequency of 10 GHz. This TIA occupies an area of 180 μ m × 118 μ m.


Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1474
Author(s):  
Zhiqun Li ◽  
Yan Yao ◽  
Zengqi Wang ◽  
Guoxiao Cheng ◽  
Lei Luo

This paper presents a low-voltage ZigBee transceiver covering a unique frequency band of 780/868/915/2400 MHz in 180 nm CMOS technology. The design consists of a receiver with a wideband variable-gain front end and a complex band-pass filter (CBPF) based on poles construction, a transmitter employing the two-point direct-modulation structure, a Ʃ-Δ fractional-N frequency synthesizer with two VCOs and some auxiliary circuits. The measured results show that under 1 V supply voltage, the receiver reaches −93.8 dBm and −102 dBm sensitivity for 2.4 GHz and sub-GHz band, respectively, and dissipates only 1.42 mW power. The frequency synthesizer achieves −106.8 dBc/Hz and −116.7 dBc/Hz phase noise at 1 MHz frequency offset along with 4.2 mW and 3.5 mW power consumption for 2.4 GHz and sub-GHz band, respectively. The transmitter features 2.67 dBm and 12.65 dBm maximum output power at the expense of 21.2 mW and 69.5 mW power for 2.4 GHz and sub-GHz band, respectively.


2013 ◽  
Vol 22 (07) ◽  
pp. 1350053 ◽  
Author(s):  
S. REKHA ◽  
T. LAXMINIDHI

This paper presents an active-RC continuous time filter in 0.18 μm standard CMOS technology intended to operate on a very low supply voltage of 0.5 V. The filter designed, has a 5th order Chebyshev low pass response with a bandwidth of 477 kHz and 1-dB passband ripple. A low-power operational transconductance amplifier (OTA) is designed which makes the filter realizable. The OTA uses bulk-driven input transistors and feed-forward compensation in order to increase the Dynamic Range and Unity Gain Bandwidth, respectively. The paper also presents an equivalent circuit of the OTA and explains how the filter can be modeled using descriptor state-space equations which will be used for design centering the filter in the presence of parasitics. The designed filter offers a dynamic range of 51.3 dB while consuming a power of 237 μW.


Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 204 ◽  
Author(s):  
Changchun Zhang ◽  
Long Shang ◽  
Yongkai Wang ◽  
Lu Tang

This paper presents a low-pass filter (LPF) for an ultra-high frequency (UHF) radio frequency identification (RFID) reader transmitter in standard SMIC 0.18 μm CMOS technology. The active-RC topology and Butterworth approximation function are employed mainly for high linearity and high flatness respectively. Two cascaded fully-differential Tow-Thomas biquads are chosen for low sensitivity to process errors and strong resistance to the imperfection of the involved two-stage fully-differential operational amplifiers. Besides, the LPF is programmable in order to adapt to the multiple data rate standards. Measurement results show that the LPF has the programmable bandwidths of 605/870/1020/1330/1530/2150 kHz, the optimum input 1dB compression point of −7.81 dBm, and the attenuation of 50 dB at 10 times cutoff frequency, with the overall power consumption of 12.6 mW from a single supply voltage of 1.8 V. The silicon area of the LPF core is 0.17 mm2.


2019 ◽  
Vol 28 (10) ◽  
pp. 1950172
Author(s):  
Mehdi Bandali ◽  
Alireza Hassanzadeh ◽  
Masoume Ghashghaie ◽  
Omid Hashemipour

In this paper, an 8-bit ultra-low-power, low-voltage current steering digital-to-analog converter (DAC) is presented. The proposed DAC employs a new segmented structure that results in low integral nonlinearity (INL) and high spurious-free dynamic range (SFDR). Moreover, this DAC utilizes a low-voltage current cell. The low-voltage characteristic of the current cell is achieved by connecting the body of MOSFET switches to their sources. Utilizing a low supply voltage along with a low bias current in the current cells results in about 623.81-[Formula: see text]W power consumption in 140-MS/s sample rate, which is very small compared to previous reports. The post-layout simulation results in 180-nm CMOS technology and [Formula: see text]-V supply voltage with the sample rate of 140[Formula: see text]MS/s show SFDR [Formula: see text] 64.37[Formula: see text]dB in the Nyquist range. The differential nonlinearity (DNL) and INL of the presented DAC are 0.1254 LSB and 0.1491 LSB, respectively.


2016 ◽  
Vol 25 (06) ◽  
pp. 1650066 ◽  
Author(s):  
Pantre Kompitaya ◽  
Khanittha Kaewdang

A current-mode CMOS true RMS-to-DC (RMS: root-mean-square) converter with very low voltage and low power is proposed in this paper. The design techniques are based on the implicit computation and translinear principle by using CMOS transistors that operate in the weak inversion region. The circuit can operate for two-quadrant input current with wide input dynamic range (0.4–500[Formula: see text]nA) with an error of less than 1%. Furthermore, its features are very low supply voltage (0.8[Formula: see text]V), very low power consumption ([Formula: see text]0.2[Formula: see text]nW) and low circuit complexity that is suitable for integrated circuits (ICs). The proposed circuit is designed using standard 0.18[Formula: see text][Formula: see text]m CMOS technology and the HSPICE simulation results show the high performance of the circuit and confirm the validity of the proposed design technique.


The different parameters define the characteristics of filter for various applications like: Biomedical applications, Defense communication systems, Wireless Communication systems etc. The mostly measured parameters for filter designing are frequency range, cut off frequency, gain, power consumption, and noise. In this paper, our work focuses on frequency range measurement at cut off frequency of Hz of second order low pass filter with designed using CMOS technology for IC fabrication. The proposed circuit gives the high frequency range at low frequency (100Hz – 10MHz) with 1mV 50Hz low power supply using complementary compound pair on the value of R=1K and C=10pH. This second order active low pass filter provides high amplification at the output with 4.861V. It is implemented and simulated on 180nm Cadence tool in terms of wide frequency range or band at cut off frequency of Hz to MHz.


Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1466
Author(s):  
Alessandro Parisi ◽  
Giuseppe Papotto ◽  
Egidio Ragonese ◽  
Giuseppe Palmisano

This paper presents a switched capacitor low-pass filter in a 28-nm fully depleted silicon on insulator CMOS technology for 77-GHz automotive radar applications. It is operated at a power supply as low as 1 V and guarantees 5-dB in-band voltage gain while providing out-of-band attenuation higher than 36 dB and a programmable passband up to 30 MHz. A double sampling technique is adopted, which allows high operating frequency to be achieved while saving power. Moreover, low-voltage biasing and common-mode feedback circuits are exploited to guarantee an almost rail-to-rail output voltage swing. The proposed filter provides an output 1-dB compression point as high as 8.7 dBm with a power consumption of 9 mW. To the authors’ knowledge, this is the first SC-based implementation of a low pass filter for automotive radar applications.


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