scholarly journals A 5.43 nV/√Hz Chopper Operational Amplifier Using Lateral PNP Input Stage with BJT Current Mirror Base Current Cancellation

2020 ◽  
Vol 10 (23) ◽  
pp. 8376
Author(s):  
Hyungseup Kim ◽  
Yongsu Kwon ◽  
Donggeun You ◽  
Hyun-Woong Choi ◽  
Seong Hyun Kim ◽  
...  
Keyword(s):  
Operational Amplifier ◽  
Low Frequency ◽  
Low Noise ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Cmos Process ◽  
Current Mirror ◽  
Input Stage ◽  
Base Current ◽  
Measured Input

This paper presents a low-noise chopper operational amplifier using a lateral PNP input stage with bipolar junction transistor (BJT) current mirror base current cancellation. The BJT has a lower noise characteristic than the metal–oxide–semiconductor (MOS) transistor, where low-noise characteristics can be achieved by implanting the BJT to the input stage of the amplifier; however, the base current of the BJT input stage causes low input impedance of the amplifier. The BJT current mirror base current cancellation technique is implemented to enhance the input impedance of the BJT input stage by canceling the base current. BJT current mirror base current cancellation is implemented with a simple scheme using NPN transistors with deep n-well in a generic complementary metal–oxide–semiconductor (CMOS) process. For further noise reduction with the BJT input stage, a chopper amplifier scheme is adopted to reduce low-frequency components such as 1/f noise terms in the low-frequency range. The prototype chip is fabricated in a 0.18-μm CMOS process. The active area of the prototype amplifier is 0.213 mm2. The measured input-referred noise is 5.43 nV/√Hz. The measured input base current of the amplifier with base current cancellation is 67.971 nA. The total amplifier current consumption is 278.3 μA, with a power supply of 3.3 V.

scholarly journals Low-Noise Chopper-Stabilized Multi-Path Operational Amplifier with Nested Miller Compensation for High-Precision Sensors

2019 ◽  
Vol 10 (1) ◽  
pp. 281 ◽  
Author(s):  
Jaesung Kim ◽  
Hyungseup Kim ◽  
Kwonsang Han ◽  
Donggeun You ◽  
Hyunwoo Heo ◽  
...  
Keyword(s):  
High Precision ◽  
Operational Amplifier ◽  
High Frequency ◽  
Flicker Noise ◽  
Low Frequency ◽  
Low Noise ◽  
Cmos Process ◽  
Miller Compensation ◽  
Chopper Stabilization ◽  
Nested Miller Compensation

This paper presents a low-noise multi-path operational amplifier for high-precision sensors. A chopper stabilization technique is applied to the amplifier to remove offset and flicker noise. A ripple reduction loop (RRL) is designed to remove the ripple generated in the process of up-modulating the flicker noise and offset. To cancel the notch in the overall transfer function due to the RRL operation, a multi-path architecture using both a low-frequency path (LFP) and high-frequency path (HFP) is implemented. The low frequency path amplifier is implemented using the chopper technique and the RRL. In the high-frequency path amplifier, a class-AB output stage is implemented to improve the power efficiency. The transfer functions of the LFP and HFP induce a first-order frequency response in the system through nested Miller compensation. The low-noise multi-path amplifier was fabricated using a 0.18 µm 1P6M complementary metal-oxide-semiconductor (CMOS) process. The power consumption of the proposed low-noise operational amplifier is 0.174 mW with a 1.8 V supply and an active area of 1.18 mm2. The proposed low-noise amplifier has a unit gain bandwidth (UGBW) of 3.16 MHz, an input referred noise of 11.8 nV/√Hz, and a noise efficiency factor (NEF) of 4.46.

scholarly journals A Robust 4-channel Micro-power Low-noise Neural Recording Amplifier for Hippocampal Cognitive Prosthesis

2020 ◽  
Author(s):  
Ming Ni ◽  
Yan Han ◽  
Jian Lei ◽  
Hakbong Kim
Keyword(s):  
Metal Oxide ◽  
Power Consumption ◽  
Process Variation ◽  
Neural Recording ◽  
Low Noise ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Cmos Process ◽  
Mos Transistor ◽  
Micro Power

Abstract Background: Recording of electrical activity of neurons is indispensable for decoding the information in the brain. The amplitude of signals recorded by electrodes is small, and it must be amplified to the level that can be digitalized by the analog-to-digital convert (ADC). A micro-power low-noise neural recording amplifier is indispensable for implant hippocampal cognitive prosthesis. When the process turns into deep submicron, the gate leakage current of the metal oxide semiconductor (MOS) transistor becomes larger and mismatch between devices becomes worsen. It is necessary to keep the neural amplifier robust in all process corners. Methods: The proposed circuit is a two-stage amplifier which can achieve a good trade-off between power consumption and noise. Four second-stage amplifiers share a common reference amplifier to reduce area and power consumption. A pseudo-resistor with high resistance is utilized to realize a very-low frequency high pass corner without external components. In order to minimize process variation, a bulk-compensated (BC) technique is adopted to maintain adequate tolerance in all corner case. Results: The 4-channel neural amplifier is designed and fabricated in a 40 nm standard complementary metal oxide semiconductor (CMOS) process. It achieves a mid-band gain of 54 dB, a bandwidth of 70 Hz to 7.7 kHz, a total input-referred noise of 3.2 μVrms , and a Noise Efficiency Factor (NEF) of 3.3 while consuming 4.68 µW from the 1.1 V supply. The core area of one channel is only 0.032 mm 2 . Conclusion: A 4-channel integrated neural recording amplifier chip with bias-compensated circuits is presented in this paper. Extensive simulations insure that the design is “center”. The chip layout is verified using design rules check (DRC) and layout versus schematic (LVS) design check with the help of verification tools. Test results shows that it is less sensitive to process variation and consumes less power compared with amplifier without bulk-compensated circuit. This makes the design robust and uniquely appropriate for low-power implant application.

A CMOS low-noise active mixer with enhanced linearity and isolation by exploiting capacitive neutralization technique

2019 ◽  
Vol 33 (18) ◽  
pp. 1950204 ◽  
Author(s):  
Benqing Guo ◽  
Huifen Wang ◽  
Jun Chen ◽  
Mohammad Mehdi Deilamsalehi
Keyword(s):  
Noise Figure ◽  
Complementary Metal Oxide Semiconductor ◽  
Low Noise ◽  
Oxide Semiconductor ◽  
Cmos Process ◽  
Frequency Range ◽  
Input Stage ◽  
Active Mixer ◽  
Input Matching ◽  
Down Conversion

In this paper, a broadband complementary metal–oxide–semiconductor (CMOS) active down-conversion mixer is presented. Specifically, a capacitor cross-coupled (CCC) transconductor serves as the input stage to reduce noise figure of the mixer while providing wideband input matching. Moreover, a capacitive neutralization technique is used to compensate the source-drain parasitic of input stage and boost loop gain of the transconductor, resulting in improved isolation and linearity. The current-reuse technique applied to the developed transconductor by stacked nMOS/pMOS architecture efficiently saves power consumption of the circuit. Implemented in the TSMC 28-nm CMOS process, post-simulations show that the proposed mixer provides a maximal conversion gain of 11.4 dB and an NF of 3.9–4.7 dB across RF input frequency range of 2–9.6 GHz. The average IIP3 of 5 dBm are obtained while the mixer core consumes 6.2 mW from a 1 V supply.

scholarly journals Universal Filter Based on Compact CMOS Structure of VDDDA

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1683
Author(s):  
Winai Jaikla ◽  
Fabian Khateb ◽  
Tomasz Kulej ◽  
Koson Pitaksuttayaprot
Keyword(s):  
Metal Oxide ◽  
Dynamic Range ◽  
Complementary Metal Oxide Semiconductor ◽  
Metal Oxide Semiconductor ◽  
Experimental Results ◽  
Oxide Semiconductor ◽  
Cmos Process ◽  
Voltage Gain ◽  
Universal Filter ◽  
Mos Transistor

This paper proposes the simulated and experimental results of a universal filter using the voltage differencing differential difference amplifier (VDDDA). Unlike the previous complementary metal oxide semiconductor (CMOS) structures of VDDDA that is present in the literature, the present one is compact and simple, owing to the employment of the multiple-input metal oxide semiconductor (MOS) transistor technique. The presented filter employs two VDDDAs, one resistor and two grounded capacitors, and it offers low-pass: LP, band-pass: BP, band-reject: BR, high-pass: HP and all-pass: AP responses with a unity passband voltage gain. The proposed universal voltage mode filter has high input impedances and low output impedance. The natural frequency and bandwidth are orthogonally controlled by using separated transconductance without affecting the passband voltage gain. For a BP filter, the root mean square (RMS) of the equivalent output noise is 46 µV, and the third intermodulation distortion (IMD3) is −49.5 dB for an input signal with a peak-to peak of 600 mV, which results in a dynamic range (DR) of 73.2 dB. The filter was designed and simulated in the Cadence environment using a 0.18-µm CMOS process from Taiwan semiconductor manufacturing company (TSMC). In addition, the experimental results were obtained by using the available commercial components LM13700 and AD830. The simulation results are in agreement with the experimental one that confirmed the advantages of the filter.

Millimeter-wave dual-mode and dual-band switchable Gilbert up-conversion mixer in 65-nm CMOS process

2021 ◽  
pp. 1-5
Author(s):  
Fang Zhu ◽  
Guo Qing Luo
Keyword(s):  
Millimeter Wave ◽  
Complementary Metal Oxide Semiconductor ◽  
Local Oscillator ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Dual Band ◽  
Cmos Process ◽  
Pumping Power ◽  
Dual Mode ◽  
Dc Power

Abstract In this paper, a millimeter-wave (MMW) dual-mode and dual-band switchable Gilbert up-conversion mixer in a commercial 65-nm complementary metal oxide semiconductor (CMOS) process is presented. By simply changing the bias, the proposed CMOS Gilbert up-conversion mixer can be switched between subharmonic and fundamental operation modes for MMW dual-band applications. With a low local oscillator pumping power of 3 dBm and low dc power consumption of 6 mW, the proposed CMOS Gilbert up-conversion mixer exhibits a measured conversion gain of −0.5 ± 1.5 dB from 37 to 50 GHz and 2.5 ± 1.5 dB from 17.5 to 32 GHz for the subharmonic and fundamental modes, respectively.

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