High performance analog and mixed signal circuits are strongly demanded in todays’system on chip systems.They found pervasive applications in A/D or D/A conversion,power management,radio frequency(RF)signal sensing a...High performance analog and mixed signal circuits are strongly demanded in todays’system on chip systems.They found pervasive applications in A/D or D/A conversion,power management,radio frequency(RF)signal sensing and processing,clock generation,etc.In this special issue,we collected 7 comprehensive reviews and 2 research articles from leading research groups,which presented state-of-art design techniques and insight forecast of development trend in this hot area.展开更多
A digital calibration technique for an ultra high-speed folding and interpolating analog-to-digital con- verter in 0.18-μm CMOS technology is presented. The similar digital calibration techniques are taken for high 3...A digital calibration technique for an ultra high-speed folding and interpolating analog-to-digital con- verter in 0.18-μm CMOS technology is presented. The similar digital calibration techniques are taken for high 3-bit flash converter and low 5-bit folding and interpolating converter, which are based on well-designed calibration reference, calibration DAC and comparators. The spice simulation and the measured results show the ADC produces 5.9 ENOB with calibration disabled and 7.2 ENOB with calibration enabled for high-frequency wide-bandwidth analog input.展开更多
A 2-Gsample/s 8-b analog-to-digital converter in 0.35μm BiCMOS process technology is presented. The ADC uses the unique folding and interpolating algorithm and dual-channel timing interleave multiplexing technology t...A 2-Gsample/s 8-b analog-to-digital converter in 0.35μm BiCMOS process technology is presented. The ADC uses the unique folding and interpolating algorithm and dual-channel timing interleave multiplexing technology to achieve a sampling rate of 2 GSPS.Digital calibration technology is used for the offset and gain corrections of the S/H circuit,the offset correction of preamplifier,and the gain and clock phase corrections between channels.As a result of testing,the ADC achieves 7.32 ENOB at an analog input of 484 MHz and 7.1 ENOB at Nyquist input after the chip is self-corrected.展开更多
This paper presents a 16-bit 2 GSPS digital-to-analog converter （DAC） in 0.18/zm CMOS technology. This DAC is implemented using time division multiplex access system architecture in the digital domain. The input dat...This paper presents a 16-bit 2 GSPS digital-to-analog converter （DAC） in 0.18/zm CMOS technology. This DAC is implemented using time division multiplex access system architecture in the digital domain. The input data is received with a two-channel LVDS interface. The DLL technology is introduced to meet the timing requirements between phases of the LVDS data and the data sampling clock. A FIFO is designed to absorb the phase difference between the data clock and DAC system clock. A delay controller is integrated to adjust the phase relationship between the high speed digital clock and analog clock, obtaining a sampling rate of 2 GSPS. The current source mismatch at higher bits is calibrated in the digital domain. Test results show that the DAC achieves 74.02 dBC SFDR at analog output of 36 MHz, and DNL less than ±2.1 LSB ＆ INL less than ±4.3 LSB after the chip is calibrated.展开更多
In this article,a graphic design method for broadband Doherty power amplifier(DPA) is proposed based on the basic principle of impedance matching with the help of Smith chart.The proposed graphic method avoids the com...In this article,a graphic design method for broadband Doherty power amplifier(DPA) is proposed based on the basic principle of impedance matching with the help of Smith chart.The proposed graphic method avoids the complex formula derivation in the traditional amplifier circuit design process,and the design process is more simple and intuitive.Besides,it only takes three steps to build the load modulation network(LMN) of two power amplifiers(PA) of the DPA.Besides,a capacitor is used to replace the parasitic parameters of the transistor,and the LMN designed in the two modes is used for exploration and comparison.Further more,the output impedance of the peaking PA is introduced to make the reflection coefficient trajectory on Smith chart lowfrequency dispersion so as to expand the bandwidth of the DPA at the output power back-off(OBO) level.It would not affect the performance of DPA in the saturation(SAT) state.In this way,a broadband DPA can be implemented easily.To validate the proposed design method,a broadband DPA operating from 1.9to 2.6 GHz is designed and measured based on the proposed method.Under the continuous-wave excitation,the fabricated DPA has a 6 dB OBO efficiency of 48%-56% and a SAT efficiency of 64%-73% from 1.75 to 2.45 GHz,and the peak output power is 48.9-49.8 dBm.展开更多
Qinghaosu 1 isolated from Artemisia annua L. has attracted great interest in recent years owing to its unique chemical structure and potent antimalarial activity, especially against chloroquine-resistant faleiprum mal...Qinghaosu 1 isolated from Artemisia annua L. has attracted great interest in recent years owing to its unique chemical structure and potent antimalarial activity, especially against chloroquine-resistant faleiprum malaria. A series of studies have been carried out on its reactions, total synthesis and analogs.For preparation of more Qing-展开更多
Droplet-based microfluidics have drawn much attention in recent years and have been successfully applied in biochemical analysis,material synthesis,and biomedical engineering.Precise and flexible manipulations of drop...Droplet-based microfluidics have drawn much attention in recent years and have been successfully applied in biochemical analysis,material synthesis,and biomedical engineering.Precise and flexible manipulations of droplets are the basis of various applications.Numerous techniques have been introduced to achieve on-demand control of droplets,including electric,magnetic,acoustic,optical,and thermal methods.Among these,the combination of acoustics and microfluidics(termed acoustofluidics)has shown great potential and advantages in droplet manipulation as it is non-invasive,high-precision,low-cost,easily integrated,and biocompatible.Here,we summarize recent works on acoustofluidic manipulations of droplet-based microfluidics.This paper is structured into three main sections.First,the commonly used acoustic devices in acoustofluidics and their working principles are introduced.Such acoustic devices include interdigital transducers,Lamb wave resonators,and bulk acoustic resonators,and generate acoustic waves with frequencies ranging from kilohertz to gigahertz.Second,the forces and effects involved in droplet manipulations using acoustofluidics are analyzed.Third,the manipulation processes of droplet microfluidics using various acoustofluidic techniques are summarized and compared with other methods,including droplet generation,mixing,splitting,fusion,sorting,transportation,and internal particle patterning.Finally,current challenges and future prospects for acoustofluidic manipulation techniques for droplet-based microfluidics are discussed.展开更多
文摘High performance analog and mixed signal circuits are strongly demanded in todays’system on chip systems.They found pervasive applications in A/D or D/A conversion,power management,radio frequency(RF)signal sensing and processing,clock generation,etc.In this special issue,we collected 7 comprehensive reviews and 2 research articles from leading research groups,which presented state-of-art design techniques and insight forecast of development trend in this hot area.
基金Project supported by the National Natural Science Foundation of China(Nos.60906009,60773025)the Postdoctoral Science Foundation of China(No.20090451423)the National Labs of Analog Integrated Circuits Foundation(No.9140C0901110902)
文摘A digital calibration technique for an ultra high-speed folding and interpolating analog-to-digital con- verter in 0.18-μm CMOS technology is presented. The similar digital calibration techniques are taken for high 3-bit flash converter and low 5-bit folding and interpolating converter, which are based on well-designed calibration reference, calibration DAC and comparators. The spice simulation and the measured results show the ADC produces 5.9 ENOB with calibration disabled and 7.2 ENOB with calibration enabled for high-frequency wide-bandwidth analog input.
文摘A 2-Gsample/s 8-b analog-to-digital converter in 0.35μm BiCMOS process technology is presented. The ADC uses the unique folding and interpolating algorithm and dual-channel timing interleave multiplexing technology to achieve a sampling rate of 2 GSPS.Digital calibration technology is used for the offset and gain corrections of the S/H circuit,the offset correction of preamplifier,and the gain and clock phase corrections between channels.As a result of testing,the ADC achieves 7.32 ENOB at an analog input of 484 MHz and 7.1 ENOB at Nyquist input after the chip is self-corrected.
文摘This paper presents a 16-bit 2 GSPS digital-to-analog converter （DAC） in 0.18/zm CMOS technology. This DAC is implemented using time division multiplex access system architecture in the digital domain. The input data is received with a two-channel LVDS interface. The DLL technology is introduced to meet the timing requirements between phases of the LVDS data and the data sampling clock. A FIFO is designed to absorb the phase difference between the data clock and DAC system clock. A delay controller is integrated to adjust the phase relationship between the high speed digital clock and analog clock, obtaining a sampling rate of 2 GSPS. The current source mismatch at higher bits is calibrated in the digital domain. Test results show that the DAC achieves 74.02 dBC SFDR at analog output of 36 MHz, and DNL less than ±2.1 LSB ＆ INL less than ±4.3 LSB after the chip is calibrated.
基金National Natural Science Foundation of China (No. 62001061)。
文摘In this article,a graphic design method for broadband Doherty power amplifier(DPA) is proposed based on the basic principle of impedance matching with the help of Smith chart.The proposed graphic method avoids the complex formula derivation in the traditional amplifier circuit design process,and the design process is more simple and intuitive.Besides,it only takes three steps to build the load modulation network(LMN) of two power amplifiers(PA) of the DPA.Besides,a capacitor is used to replace the parasitic parameters of the transistor,and the LMN designed in the two modes is used for exploration and comparison.Further more,the output impedance of the peaking PA is introduced to make the reflection coefficient trajectory on Smith chart lowfrequency dispersion so as to expand the bandwidth of the DPA at the output power back-off(OBO) level.It would not affect the performance of DPA in the saturation(SAT) state.In this way,a broadband DPA can be implemented easily.To validate the proposed design method,a broadband DPA operating from 1.9to 2.6 GHz is designed and measured based on the proposed method.Under the continuous-wave excitation,the fabricated DPA has a 6 dB OBO efficiency of 48%-56% and a SAT efficiency of 64%-73% from 1.75 to 2.45 GHz,and the peak output power is 48.9-49.8 dBm.
文摘Qinghaosu 1 isolated from Artemisia annua L. has attracted great interest in recent years owing to its unique chemical structure and potent antimalarial activity, especially against chloroquine-resistant faleiprum malaria. A series of studies have been carried out on its reactions, total synthesis and analogs.For preparation of more Qing-
基金financial support from the National Natural Science Foundation of China(NSFC):Grant Nos.22427807 and 62174119Tianjin National Key Laboratory Major Project No.24ZXZSSS00290.
文摘Droplet-based microfluidics have drawn much attention in recent years and have been successfully applied in biochemical analysis,material synthesis,and biomedical engineering.Precise and flexible manipulations of droplets are the basis of various applications.Numerous techniques have been introduced to achieve on-demand control of droplets,including electric,magnetic,acoustic,optical,and thermal methods.Among these,the combination of acoustics and microfluidics(termed acoustofluidics)has shown great potential and advantages in droplet manipulation as it is non-invasive,high-precision,low-cost,easily integrated,and biocompatible.Here,we summarize recent works on acoustofluidic manipulations of droplet-based microfluidics.This paper is structured into three main sections.First,the commonly used acoustic devices in acoustofluidics and their working principles are introduced.Such acoustic devices include interdigital transducers,Lamb wave resonators,and bulk acoustic resonators,and generate acoustic waves with frequencies ranging from kilohertz to gigahertz.Second,the forces and effects involved in droplet manipulations using acoustofluidics are analyzed.Third,the manipulation processes of droplet microfluidics using various acoustofluidic techniques are summarized and compared with other methods,including droplet generation,mixing,splitting,fusion,sorting,transportation,and internal particle patterning.Finally,current challenges and future prospects for acoustofluidic manipulation techniques for droplet-based microfluidics are discussed.
