The Kynix Blog

The LTC2185 is a 125Msps 16-bit ADC with excellent noise and linearity performance while only consuming 185mW per channel. It is ideal for demanding low power applications that require excellent AC performance. A high performance ADC like the LTC2185 requires a high performance amplifier driving it to maintain the excellent performance. The ADA4927-1 delivers the linearity performance required by the LTC2185 while only consuming 215mW. The well designed package of the ADA4927-1 allows for a simple layout that reduces parasitic capacitance in the feedback path that can erode the phase margin of the amplifier. This combination of ADC and driver allows excellent performance from 62.5-125MHz a region where other high speed amplifiers are lacking.  The LTC2185 is a two-channel simultaneous sampling parallel ADC which offers a choice of full-rate CMOS, or double data rate (DDR) CMOS/LVDS digital outputs. Pin-compatible speed grade options include 25Msps, 40Msps, 65Msps, 80Msps and 105Msps with approximate power dissipation of just 1.5mW/Msps per channel. It includes popular features such as the digital output randomizer and alternate bit polarity (ABP) mode that minimize digital feedback when using parallel CMOS outputs.  Analog full power bandwidth of 550MHz and ultralow jitter of 0.07psRMS allows under-sampling of IF frequencies with excellent noise performance. To maintain this level of performance the LTC2185 needs to be driven with an appropriate amplifier like the ADA4927-1. The ADA4927 is a high speed differential current feedback amplifier. Fabricated on Analog Devices’ silicon-germanium process, the ADA4927-1 has excellent distortion and an input voltage noise of only 1.3nV/rtHz. This allows it to drive high speed ADCs like the LTC2185. The gain of the ADA4927-1 is set with external feedback resistors located next to the input pins.  By keeping the feedback pins and input pins close on the package, the ADA4927-1 provides a clean layout and minimizing the parasitic capacitance in the feedback network. This make the ADA4927-1 an ideal choice for driving high performance ADCs, like the LTC2185, from DC to 125 MHz. Figure 1 shows a schematic of the ADA4927-1 driving the LTC2185. The corresponding layout is shown in figure 2.  The feedback pins on the ADA4927-1 are adjacent to the input pins which minimizes the parasitic capacitance of the feedback node and improves the phase margin of the amplifier. It also Simplifier the layout by making it possible to place feedback resistors directly across the two pins and not having additional trace length in the feedback path. There is a simple filter between the amplifier and ADC that reduces the wideband noise of the amplifier and improves the SNR of the system. This filter also attenuates the sampling glitches from the ADC before they reach the amplifier. This helps keep the output network of the ADA4927 from oscillating in response to these glitches. This filter network can be modified to accommodate a wide range of input bandwidth requirements. (Figure 1:  Schematic showing an ADA4927-1 driving one channel of the LTC2185)(Figure 2:  Layout showing an ADA4927-1 driving once channel of the LTC2185)Figure 3 and figure 4 show the SNR and SFDR of the LTC2185 and ADA4927-1 combination. The SFDR stays above 67dB out to 125MHz while the SNR is better than 63dB to the same frequency. This combination only consumes 250mW. With a sample rate of 125Msps, this combination provides good performance through the entire 2nd Nyquist zone where other amplifiers begin to have poor linearity.  (Figure 3:  SNR of the LTC2185 driven with the ADA4927-1)(Figure 4:  SFDR of the LTC2185 driven with the ADA4927-1) Using the ADA4927-1 to drive the LTC2185 provides excellent linearity while keeping the power consumption low. The fact that the ADA4927-1 stays very linear out to 125MHz allows this ADC amplifier combination to be used in demanding communication and medical applications that require the use of the second Nyquist zone of the LTC2185. The pin out of the ADA4927-1 and filter design minimize the complexity of the layout while maintaining excellent performance on a low power budget. Ref.KY32-LTC2185KY362-ADA4927-1 

The world's most precise clock has been fine-tuned to boost radar and GPS capabilities.The Cryogenic Sapphire Oscillator, or Sapphire Clock, has been enhanced by researchers from the University of Adelaide in South Australia to achieve near attosecond capability. The oscillator is 10-1000 times more stable than competing technology and allows users to take ultra-high precision measurements to improve the performance of electronic systems. Increased time precision is an integral part of radar technology and quantum computing, which have previously relied on the stability of quartz oscillators as well as atomic clocks such as the Hydrogen Maser. Atomic clocks are the gold-standard in time keeping for long-term stability over months and years. However, electronic systems need short-term stability over a second to control today's devices. The new Sapphire Clock has a short-term stability of better than 1x10-15, which is equivalent to only losing or gaining one second every 40 million years, 100 times better than commercial atomic clocks over a second. The original Sapphire Clock was developed by Professor Andre Luiten in 1989 in Western Australia before the team moved to South Australia to continue developing the device at the University of Adelaide. Lead researcher Martin O'Connor said the development group was in the process of modifying the device to meet the needs of various industries including defence, quantum computing and radio astronomy. The 100cm x 40cm x 40cm clock uses the natural resonance frequency of a synthetic sapphire crystal to maintain a steady oscillator signal.Associate Professor O'Connor said the machine could be reduced to 60 per cent of its size without losing much of its capability."Our technology is so far ahead of the game, it is now the time to transfer it into a commercial product," he said. "We can now tailor the oscillator to the application of our customers by reducing its size, weight and power consumption but it is still beyond current electronic systems." The Sapphire Clock, also known as a microwave oscillator, has a 5 cm cylinder-shaped crystal that is cooled to -269C. Microwave radiation is constantly propagating around the crystal with a natural resonance. The concept was first discovered by Lord Rayleigh in 1878 when he could hear someone whispering far away on the other side of the church dome at St Paul's Cathedral. The clock then uses small probes to pick up the faint resonance and amplifies it back to produce a pure frequency with near attosecond performance."An atomic clock uses an electronic transition between two energy levels of an atom as a frequency standard," Associate Professor O'Connor said."The atomic clock is what is commonly used in GPS satellites and in other quantum computing and astronomy applications but our clock is set to disrupt these current applications."  The lab-based version already has an existing customer in the Defence Science and Technology Group (DST Group) in Adelaide, but Associate Professor O'Connor said the research group was also looking for more clients and was in discussion with a number of different industry groups. The research group is taking part in the Commonwealth Scientific and Industrial Research Organisation's (CSIRO's) On Prime pre-accelerator program, which helps teams identify customer segments and build business plans. Ref.KY45-E3X-DA6KY163-TX179

CatalogAC Charging1) 1ϕ On-Board Slow Charging2) 3ϕ On-Board Fast ChargingDC Charging1) Off-Board Fast Charging2) Off-Board Rapid ChargingSummarizing with Key Points Overview: The effectiveness and cost of battery electric vehicles are directly related to the batteries and charging technologies that are employed. Several categories of wired charging technologies for battery electric vehicles are discussed in depth in this article. Based on the input voltage type delivered to the battery electric vehicle (BEV) inlets, the wire-based technologies are divided into two categories: AC-charging technologies and DC-charging technologies. 1ϕ on board (OB) slow charging technology and 3ϕ OB fast charging technology make up the first set. The latter category is divided into two groups: off-board fast charging technologies and off-board rapid charging technologies, as indicated in Fig. 1.Fig. 1. Overall charging system for BEVs using wired/wireless. Source: IEEE Access AC ChargingAC charging indirectly charges the battery via the onboard charger (OBC), which can be classified into two groups: 1ϕ OB slow charging and 3ϕ OB fast charging. 1) 1ϕ On-Board Slow Charging1ϕ OB slow charging usually requires multiple conversions (AC-DC and DC-DC), which leads to low-voltage ripples and a relatively high power rating. So, it is often used as an OBC inside BEVs, such as for level 1 AC charging (input voltage: 1ϕ 120 or 220 V, charging power: below 2 kW, and battery voltage (VB): DC 240–325 V) in a number of BEV models on the market (e.g., Tesla Model 3, Toyota RAV4, etc.). Fig. 2 shows a two-stage 1ϕ OBC that is easy to understand for BEVs. The battery is charged in the following ways: First, the grid voltage is changed so that an AC/DC converter can feed the power factor correction (PFC) circuit. Then, the PFC circuit's output voltage is sent to the intermediate DC-link bus, which is then turned into a controlled DC output voltage by an isolated DC/DC converter (such as a full-bridge (FB), flyback, etc.). This is how safe and effective battery charging is achieved. Note that a galvanic transformer is used at the DC-DC stage to get the galvanic isolation. Fig. 2(a) and 2(b) show unidirectional and bidirectional chargers, which can be set up in two different ways based on how the power flows. The unidirectional charger makes it easier for a utility grid to send power to a heavy load, like multiple BEVs, at the same time. By controlling the phase angle of the supply current, a unidirectional active front-end rectifier can provide power without draining the battery. This is one of the main benefits of this type of rectifier. So, a unidirectional charger is a good way to get a lot of BEVs on the road and actively control the charging current. The bidirectional charger can be used in both grid-to-vehicle (G2V) and vehicle-to-grid (V2G) technologies, unlike the unidirectional charger. A few disadvantages are that the battery lasts less when it is charged and discharged often, and the cost of the charging system goes up. A lot of safety and anti-islanding measures are also built into this type of charging technology. Fig. 2 shows one of the most common ways to charge a 1ϕ OB slowly. This is level 1, which has a power output of about 2 kW and a charging time of 6 hours or more. Fig. 2. 1ϕ on-board slow charging topologies. (a) Unidirectional topology. (b) Bidirectional topology. Source: IEEE Access 2) 3ϕ On-Board Fast Charging The 3ϕ OB fast charging technologies can charge batteries faster than the 1ϕ OB slow charging technologies because they have a medium power rating (about 20 kW). This means that they can charge the battery up to 80% in between 2 - 3.5 hours. So, they can be used for an OBC in BEVs like level 3 (i.e., input voltage: 3ϕ 280–420 V, charging power: up to 50 kW, and battery voltage (VB): DC 320–400 V): (e.g., Smart FortWo ED, Tesla Model 3, Toyota RAV4, etc.). Most of these charging technologies use Dual-Active-Bridge (DAB) topologies. Fig. 3 shows how the current 3ϕ OB fast charging technologies work. Because it is easy to use, this method is better for almost all BEVs on the market.Fig. 3. 3ϕ On-Board Fast Charging. (a) Unidirectional topology. (b) Bidirectional topology. Source: IEEE Access DC ChargingDC charging technologies for BEVs can be put into two groups: off-board fast charging and off-board rapid charging. 1) Off-Board Fast ChargingThe rectifying unit at the charging station makes it possible for these technologies to directly charge the battery of a BEV. Because of this, they can make the driving system smaller and lighter as a whole. Most of the time, these charging technologies use DAB topologies. These kinds of charging technologies are known for how quickly they charge (specifically, for their charging times below one hour). Companies with good reputations, like Tesla, BMW, Nissan, and Hyundai, have recently started to offer fast DC charging stations that can charge batteries in an hour. Fig. 4 shows the off-board fast charging technologies, which mostly use a 3ϕ power source with a power level between 20 - 120 kW, a charging time of less than one hour, and a battery voltage between DC 320 - 450 V. Fig. 4. 3ϕ off-board fast charging topologies. (a) Unidirectional topology (b) Bidirectional topology. Source: IEEE Access 2) Off-Board Rapid ChargingRapid charging technologies, which use more power and charging current, are an extension of fast charging technologies. In these ways of charging, the time it takes to charge is shorter, and a battery of a BEV with a DC 320–500 V can be charged up to 80% in 15 minutes. One of the best-known fast chargers, made by Tesla, is powered by DC 480 V and 250 kW. As of March 2020, Tesla had successfully run 16,013 superchargers at 1,826 charging stations around the world for its Model S, Model 3, Model X, and Model Y BEVs. For example, the Model S has a charging current of 80 A. For 85 kWh, it takes about 20, 40, and 75 minutes to charge the battery to 50%, 80%, and 100%, respectively. Fig. 5 shows the rapid charging topology, in which a high-power DC current that can reach 400 A charges the battery. The figure shows a 3ϕ unidirectional topology and a 3ϕ bidirectional topology, both of which are off-board configurations. Fig. 5. 3ϕ off-board rapid charging topologies. (a) Unidirectional topology. (b) Bidirectional topology. Source: IEEE Access Summarizing with Key Points:Some of the takeaways from the article are as follows:Based on how input voltage is given to the battery vehicle, battery electric vehicles are categorized into two categories: AC-charging technologies and DC-charging technologies.During AC charging, the onboard charger, which can be divided into two groups: 1ϕ OB slow charging and 3ϕ OB fast charging, indirectly charges the battery. And DC charging is divided into two categories: 3ϕ OB fast charging and 3ϕ OB rapid charging.Depending on how the power flows, 1ϕ on-board unidirectional and bidirectional chargers for slow charging can be set up in one of two ways. Level 1 charging, which takes 6 hours or longer to complete and has a power output of around 2 kW, is the most popular method. 3ϕ OB fast charging techniques can charge batteries by up to 80% in just 2 to 3.5 hours. These technologies are superior for practically all available electric since they use dual active bridge topologies and are simple to use.Fast DC charging stations that can charge batteries in an hour are now being offered by reputable firms. DAB topologies are notable for how quickly they charge batteries.Off-board fast charging methods employ a 3ϕ power source with a power output ranging from 20 to 120 kW, a charging time of under an hour, and a battery voltage range of DC 320 to 450 V.Off-board quick charging methods employ greater power and charging current while also speeding up the charging process. 16,013 superchargers at 1,826 charging stations around the world have been successfully used by Tesla. This blog post is part of a full research article from IEEE Access. The featured image is used courtesy of OPEN AI.

In autumn, an abundance of fallen leaves from deciduous phoenix trees are scattered around the streets in Northern China. These leaves are generally burned in the colder season, exacerbating the country's air pollution problem.Investigators in Shandong, China, recently discovered a new method to convert this organic waste matter into a porous carbon material that can be used to produce high-tech electronics. The advance is reported in the Journal of Renewable and Sustainable Energy, by AIP Publishing. The investigators used a multistep, yet simple, process to convert tree leaves into a form that could be incorporated into electrodes as active materials. The dried leaves were first ground into a powder, then heated to 220 degrees Celsius for 12 hours. This produced a powder composed of tiny carbon microspheres. These microspheres were then treated with a solution of potassium hydroxide and heated by increasing the temperature in a series of jumps from 450 to 800 C. The chemical treatment corrodes the surface of the carbon microspheres, making them extremely porous. The final product, a black carbon powder, has a very high surface area due to the presence of many tiny pores that have been chemically etched on the surface of the microspheres. The high surface area gives the final product its extraordinary electrical properties.(Scanning Electron Microscopy (SEM) image of porous carbon microspheres.)The investigators ran a series of standard electrochemical tests on the porous microspheres to quantify their potential for use in electronic devices. The current-voltage curves for these materials indicate that the substance could make an excellent capacitor. Further tests show that the materials are, in fact, supercapacitors, with specific capacitances of 367 Farads/gram, which are over three times higher than values seen in some graphene supercapacitors. A capacitor is a widely used electrical component that stores energy by holding a charge on two conductors, separated from each other by an insulator. Supercapacitors can typically store 10-100 times as much energy as an ordinary capacitor, and can accept and deliver charges much faster than a typical rechargeable battery. For these reasons, supercapacitive materials hold great promise for a wide variety of energy storage needs, particularly in computer technology and hybrid or electric vehicles. This research is led by Hongfang Ma of Qilu University of Technology, and has been heavily focused on looking for ways to convert waste biomass into porous carbon materials that can be used in energy storage technology. In addition to tree leaves, the team and others have successfully converted potato waste, corn straw, pine wood, rice straw and other agricultural wastes into carbon electrode materials. Professor Ma and her colleagues hope to improve even further on the electrochemical properties of porous carbon materials by optimizing the preparation process and allowing for doping or modification of the raw materials. The supercapacitive properties of the porous carbon microspheres made from phoenix tree leaves are higher than those reported for carbon powders derived from other biowaste materials. The fine scale porous structure seems to be key to this property, since it facilitates contact between electrolyte ions and the surface of the carbon spheres, as well as enhancing ion transfer and diffusion on the carbon surface. The investigators hope to improve even further on these electrochemical properties by optimizing their process and allowing for doping or modification of the raw materials.  This article is authored by Hongfang Ma, Zhibao Liu, Xiaodan Wang and Rongyan Jiang and is published in Journal of Renewable and Sustainable Energy.  Ref.KY36-5KK560KOAAM(capacitor)KY36-DEBB33F222KA3B(capacitor)KY605-NH12VP(rechargeable battery)  

SummaryPublished in the Joural Nature Materials in Nov.13,2017,reaearchers from Princeton University,the Georgia Institute of Technology and Humboldt Uniersity in Berlin is pointing the way to possibly more widespread use of organic electronics. Their research focuses on organic semiconductors,a class of materials prized for their applications in emerging technologies such as flexible electronics, solar energy conversion, and high-quality color displays for smartphones and televisions. In the short term, the advance should particularly help with organic light-emitting diodes that operate at high energy to emit colors such as green and blue.  Body“Organic semiconductors are ideal materials for the fabrication of mechanically flexible devices with energy-saving low-temperature processes,” said Xin Lin, a doctoral student in electrical engineering at Princeton and the lead author. “One of their major disadvantages has been their relatively poor electrical conductivity. In some applications, this can lead to difficulties and inefficient devices. We are working on new ways to improve the electrical properties of these organic semiconductors.” Semiconductors, typically made of silicon, are the foundation of modern electronics because engineers can take advantage of their unique properties to control electrical currents. Among many applications, semiconductor devices are used for computing, signal amplification and switching( signal switches ). They are used in energy-saving devices such as light-emitting diodes and devices that convert energy such as solar cells. In the doping process used to make semiconductors their chemical makeup is modified by adding a small amount of chemicals or impurities. By carefully choosing the type and amount of dopant, researchers are able to alter the electronic structure and electrical behaviour of the semiconductor in a number of ways. As the article shows,researchers have developed an approach for greatly increasing the conductivity of organic semiconductors,which are formed of carbon-based molecules rather than silicon atoms. The dopant, a ruthenium-containing compound, is a reducing agent, which means it adds electrons to the organic semiconductor as part of the doping process. The addition of the electrons is the key to increasing the semiconductor’s conductivity. The compound belongs to a newly introduced class of dopants called dimeric organometallic dopants. Unlike many other powerful reducing agents, these dopants are stable when exposed to air but still work as strong electron donors both in solution and solid state. Seth Marder and Stephen Barlow from the Georgia Institute of Technology, who led the development of the new dopant, called the ruthenium compound a “hyper-reducing dopant.” They said it is unusual, not only in its combination of electron donation strength and air stability, but in its ability to work with a class of organic semiconductors that have previously been very difficult to dope. In studies conducted at Princeton, the researchers found that the new dopant increased the conductivity of these semiconductors about a million times. The ruthenium compound is a dimer, which means it consists of two identical molecules, or monomers, connected by a chemical bond. As is, the compound is relatively stable and, when added to these difficult-to-dope semiconductors, it does not react and remains in its equilibrium state. That posed a problem because to increase the conductivity of the organic semiconductor, the ruthenium dimer needs to react with the semiconductor it and then split apart. The researchers looked for different ways to break up the ruthenium dimer and activate the doping, eventually they added energy by irradiating with ultraviolet light, which effectively excited the molecules in the semiconductor and initiated the reaction. Under exposure to the light, the dimers split into monomers, and the conductivity rose. "Once the light is turned off, one might expect the reverse reaction to occur" and the increased conductivity to disappear, Marder said. "However, this is not the case." The researchers found that the ruthenium monomers remained isolated in the semiconductor even though thermodynamics should return the molecules to their original configuration as dimers. The team's hypothesis is that the monomers are scattered in the semiconductor in such a way that it is very difficult for them to return to their original configuration and re-form the ruthenium dimer. They are, according to the team “kinetically trapped." The researchers also discovered that doping was continuously re-activated by the light produced by the device. The light activates the system more, which leads to more light production and more activation until the system is fully activated, Marder said. "This alone is a novel and surprising observation." The work was supported in part by the National Science Foundation and the U.S. Department of Energy. Article edited by kynix   

Ion Transistors for the transport of both positive and negative ions, as well as biomolecules had been previously developed by a group of Organic Electronics research team at Linköping University. Now Tybrandt has now succeed in developing circuits using these Transistors similar to traditional silicon electronics. In essence of this technology we can build computer chips that can directly interface with our body cells.The major advantage of chemical circuit is that the charge carrier consists of chemical substances with various functions and this gives us new opportunities to regulate and control signal paths of Human Body Cells.In a conventional transistor there are three terminals Gate, Source and Drain. When signal is applied to Gate terminal, electrons flow from Source to Drain. Electrons are the charge carrier in conventional transistor, but in the new Ion Transistor the ionic neurotransmitter acetylcholine is the charge carrier. NAND gates and Inverters can be created using these Ion transistors, which means that it can be used to implement any logic function.Magnus Berggren, Professor of Organic Electronics and leader of the research group says that, it can be used to send signals to muscle synapses when our muscle signalling system may not works for some reasons and our chips works with common signalling substances such as acetylcholine.The research in Ion Transistors which can control and transport ions and charged biomolecules was begun before 3 years by Berggren (professor in Organic Electronics at the Department of Science and Technology at Linköping University) and Tybrandt (a doctoral student). Researchers at Karolinska Institute then used this Transistors to control the delivery of the signalling substance acetylcholine to individual cells. It hopes that it can restore the lost movement of paralysed peoples.Mr. Tybrandt in conjunction with Robert Forchheimer (Professor of Information Coding at LiU) has taken the next steps by developing chemical chips which contains logic gates, that allows the construction of all logic functions.Ref:KY56-C4706KY56-KSC5024RTUKY56-MJL21193G