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ABOUT KNYIX OverviewKynix Semiconductor HongKong Limited was founded in 2008, which specializes in electronic components distribution business. With an experienced research and development,sales and management team, we have gradually established an excellent reputation and credibility in our international business. As our business philosophy, honesty and ethics are always in the first place when we serve our customers. For the accurate quotation, excellent credit, reasonable price, reliable quality, fast delivery, authentic service, we have won favorable comments of our customers.After years of steady development, Kynix has established good relationships of cooperation with well-known brand agents and manufacturers in Japan, Korea and some western countries (LG,INTEL,Foxconn,etc.). Also we have stable and good supply channels. At the meanwhile, we attach great importance to relationships with  everyone in this field, and cherish every opportunity of cooperation and sharing. Company profile Company nameKynix Semiconductor HongKong LimitedYear Established2008Area of BusinessElectronic components distributionAddress of companyFlat 08,4/F Shing Yip Ind Bldg,19,19-21 Shing Yip Street Kwun Tongkowloon Hong KongProductsOptical devices, embedded systems, semiconductors, circuit protection components, passive components, connectors, sensors, etc.ServicesOffering over 60 days after-sales services  Development History   Kynix’s Advantages    ·Our Operation SystemStrong enterprise management system, high intelligent procurement system, super stable order system, strong warehouse management system, professional inspection technology of professional shipment,convenient and efficient delivering system, applicable to PC/mobile devices. We are pleasure to serve for over 9000 clients around the world. We have spend 13 years to meet the needs from our worldwide clients and satisfy them, so we know clearly about the importance of safe delivery, timely after-sales service and  intimate service.           ·Warehouse ManagementWe strictly comply with the warehouse management rules. By implementing ERP system, we master the warehouse data accurately, which fundamentally ensure the accuracy and unity of actual operation, delivery status and the backend database.  At the same time, it further improves the working efficiency and accomplishes the scientific management of the warehouse.   Corporate Culture  Kynix is constantly committed to constructing a strong corporate culture and sharing its prosperity with all of its employees. Kynix is devoted to carrying out its core corporate culture of “honesty, efficiency and reliability”, adhering to the development concept of its quality culture under the theme of human-nurturing before goods-building and earnestness, etc. Close cooperation among departments plays a key role in a company’s operation. To ensure that all of our customers can get reliable and efficient service promptly, Kynix sales department always pays high attention to each RFQ sent by our customers and proceeds it in the first place. Our purchasing department is responsible for goods purchasing and quality assurance. Every staff in Kynix is trying their best to do their jobs well, which makes our company better and better.   Customers’ Reviews With the good cooperation, Kynix won a lot of praise from our customers. Follows are some reviews from them. “Both price and goods is suitable for my design! The seller’s service is really good! Anyway, I am indeed content with shopping of this time. Recommending Kynix strongly to everyone who wants to purchase electronic components.”——Nikita Silva “About one year ago I ordered a first shipment of parts from Kynix, so I′m giving a long-therm evaluation here. Kynix in my opinion is a reputable, professional supplier with great pricing, communication, care taking/handling and reassurance that no fake-parts are sold. I am very confident in their service and I′m currently preparing another shipment of same size......”——Florian Poeschko “Great seller, the best service.Very pleasant to deal business with such company.”——Crystal Ling “I placed a trial order in Kynix Semiconductor’s website, and I received the parts.They are all good and well packaged. The service is also excellent. I think I will but again!”——Madele “This is my second order. I got an excellent service and the delivery is very fast. I am very satisfied. Thank you.”——Gustavo “I am a regular customer of Kynix Semiconductor. After years of purchasing components here, I have to say these good points about it. And these are the reason why I want to recommend Kynix if you want to buy components for your design. Items: Standard, hard-to-get and long obsolete components like - Transistors (e.g. Sanyo 2SK44, Fairchild FQPF11P06) - Diodes (e.g. Rohm 1S2473, Toshiba 1S1588) - Integrated circuits (e.g. National Semiconductors LM308)  Quotation: The quotation (pre-buy) was turned around fast, it was accurate and clear (including shipping costs). Several parts needed communication on my behalf with a sales assistant who was able to answer every question I had (e.g. is component definitely from the manufacturer I specified, can I see another picture, etc.). All my necessities we′re met and all components/manufacturers could be found. Pictures were sent for confirmation where needed and matched parts sent.  Parts: After working with the parts over the past year I can say they are all of genuine brand/manufacturer and I haven′t yet had a single defective component.  Packaging: All parts were sent in sealed soft-bags/hard batch-casings and accurately labelled (part number, manufacturer and amount). Bags can be opened and sealed again which makes them great for both storage and regular use.  Shipment: The whole shipment was packed carefully and no damage to any parts. It was delivered faster as expected and customs were taken care of hassle-free. The cost was very reasonable.  Pricing: The pricing was excellent especially with greater amounts which was why I could purchase a greater amount for surplus (In some instances several hundreds of them.) I feel really good with their good quality and excellent service. Hope this evaluation can help you!”——Pinellis Sam   Kynix’s ProspectIn 2015, Kynix Semiconductor’s annual value of production had reached $50 million. And our partners in electronics field increased to 700 in 2016. Now the Chinese version of Kynix website is moving ahead and will be launched soon. ContactIf you want to know more about Kynix Semiconductor and our products, please view our website! Or you can contact us through our email: info@kynix.com. Come and buy good products at lower price from us! 

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

  A MOSFET is a four-terminal device having source(S), gate (G), drain (D), and body (B) terminals. In general, the body of the MOSFET is in connection with the source terminal thus forming a three-terminal device such as a field-effect transistor. MOSFET is generally considered as a transistor and employed in both analog and digital circuits. This is the basic introduction to MOSFET. Let’s step into the world of MOSFET and find out its secret.     Catalog   I. What is MOSFET? 1.1 Brief Introduction 1.2 MOSFET Structure 1.3 Electrical Symbol and Types 1.4 MOSFET Operating Principle II. MOSFET Selection III. MOSFET Gate Material IV. MOSFET Advantage V. MOSFET Technology VI. Common MOSFET Failures VII. MOSFET Well-known Brands FAQ   I. What is MOSFET?   1.1 Brief Introduction     MOSFET(metal-oxide-semiconductor field-effect transistor) is a type of field-effect transistor (FET), most commonly fabricated by the controlled oxidation of silicon. It has an insulated gate, whose voltage determines the conductivity of the device. This video will cover the basics of what you need to use it in your circuit, including calculating if you need a heat sink or not.   MOSFET (metal-oxide semiconductor field-effect transistor) is a kind of field effect transistors (FET), that is, the gate of metal layer (M) is separated by oxide layer (O) to control the semiconductors (S) by the field effect transistor.   1.2 MOSFET Structure   Fig. 1 mosfet body structure Fig. 1 is a cross-sectional view of a typical N-channel enhanced NMOSFET diagram. a P-type silicon semiconductor material is used as a substrate, two N-type regions are diffused on the surface of the substrate, a layer of silicon dioxide (SiO2) insulating layer is covered on the substrate, and finally, two holes are formed by using an etching method over the N region. The metallization method is used to make three electrodes: G (gate), S (source), and D (drain) in the insulating layer and the two holes, respectively.   From Fig. 1, we can see that the gate G is insulated from drain D and source S, and there are two PN junctions between D and S. In general, the substrate and the source S are connected internally, in other words, there is a PN junction between D and S.   Fig. 1 is a basic block diagram of a common n-channel enhancement MOSFET. To improve the performance of some parameters, such as improving the working current, increasing the working voltage, reducing the on-resistance, improving the switching characteristic, and so on. With different structures and processes, there are VMOS, DMOS, TMOS, etc. Although their structures are different, the working principle is the same.   1.3 Electrical Symbol and Types Fig. 2 mosfet symbols There are many variations in circuit symbols commonly used in MOSFET. The most common design is to represent the channel in a straight line, two lines perpendicular to the channel to represent the source and drain, and the left and the channel parallel and shorter lines to represent the grid. Sometimes a straight line representing the channel is replaced by a broken line to distinguish between an enhancement mode MOSFET or a depletion mode MOSFET and each mode divided into two types respectively, NMOSFET and PMOSFET. Fig. 3 NMOSFET and PMOSFET     Depletion Mode: the Gate-Source voltage of a transistor switches the device “OFF”. The depletion-mode MOSFET is equivalent to a “Normally Closed” switch.   Fig. 4 structure and electrical symbol  (depletion mode mosfet)   Enhancement Mode: the Gate-Source voltage of a transistor switches the device “ON”. The enhancement-mode MOSFET is equivalent to a “Normally Open” switch.   Fig. 5 enhancement type MOSFET(channel structure) Since the MOSFET on the integrated circuit chip is a four-terminal component, there is a bulk or body except for the gate, source and drain. The arrow extending from the channel to the right can indicate that the component is an NMOSFET or PMOSFET. In addition, the arrow direction is always pointed from the P end to the N end, so the arrow points from the channel to the base is the P-type MOSFET, abbreviated PMOS.   On the contrary, if the arrow points from the base to the channel, the base is P-type, and the channel is N-type, which is the N-type MOSFET. In a typical discrete device, that base and source are typically connected together so that the distributed MOSFET is typically a three-terminal element. Whereas a MOSFET in an integrated circuit, the polarity of the base is not indicated because of the use of the same base, and a circle is added to the gate terminal of the PMOS to distinguish.     P-Channel MOSFET: It has a P-Channel region between source and drain. It is a four-terminal device such as gate, drain, source, body. The drain and source are heavily doped p+ region and the body or substrate is n-type. The flow of current is positively charged holes. When we apply the negative gate voltage, the electrons present under the oxide layer are pushed downward into the substrate with a repulsive force. The depletion region populated by the bound positive charges which are associated with the donor atoms. The negative gate voltage also attracts holes from the p+ source and drain region into the channel region.       N- Channel MOSFET: It has an N-channel region between source and drain. It is a four-terminal device such as gate, drain, source, body. In this type of MOSFET, the drain and source are heavily doped n+ region and the substrate or body is P-type. The current flows due to the negatively charged electrons. When we apply the positive gate voltage the holes present under the oxide layer pushed downward into the substrate with a repulsive force. The depletion region is populated by the bound negative charges which are associated with the acceptor atoms. The electron's reach channel is formed. The positive voltage also attracts electrons from the n+ source and drains regions into the channel. Now, if a voltage is applied between the drain and source the current flows freely between the source and drain and the gate voltage controls the electrons in the channel. Instead of positive voltage if we apply negative voltage a hole channel will be formed under the oxide layer.       Therefore, the MOSFET has 4 modes: P-channel enhancement mode, P-channel depletion mode, N-channel enhancement mode, N-channel depletion mode. Their circuit symbols and application characteristic curves are shown in the following figure.  Fig. 6 circuit symbols and application characteristic curves of MOSFET 1.4 MOSFET Operating Principle The internal structure and electrical symbols of power MOSFET can be divided into NPN type and PNP type. That is, the source and drain poles of the N-channel FET are connected to the N-type semiconductor, and the source and drain of the P-channel FET are connected to the P-type semiconductor. We know that the output current of the general transistor is controlled by the input current. But for field-effect transistors, the output current is controlled by the input voltage (or field voltage), which can be considered to be minimal or no input current, causing the device to have a high input impedance, and it is the reason why we call it a FET.   The working principle of power MOSFET is as follows: adding positive power supply between drain and source, and no voltage between gate and sources. The PN junction J1 formed between drain and source is anti-biased, and there is no current flow between drain-source.    Conductive: adding the positive voltage UGS, the gate is insulated between the gate and source, so there will be no gate current flowing through. However, the positive voltage of the gate pushes the hole in the P region below it and attracts the minority electron in the P region to the surface of the P region below the gate when the UGS is greater than the UT (on voltage or threshold voltage). The electron concentration on the surface of the P region under the gate will exceed the hole concentration, making the P-type semiconductor invert into the N-type. For the inversion layer, the N-channel is formed and the PN junction J1 is disappeared, and meanwhile, the drain electrode and the source electrode are conductive.    Basic static characteristics of power MOSFET: Its transfer and output characteristics are shown in Fig. 7.   Fig. 7 transfer and output characteristics of mosfet The relationship between drain current ID and voltage UGS between gate and source is called the transfer characteristic of MOSFET. When ID is large, the relationship between ID and UGS is approximately linear, and the slope of the curve is defined as grid-anode transconductance Gfs.   The voltage-current characteristic (output characteristics) of drain include the cut-off region (corresponding to the cut-off region of GTR), the saturated region (corresponding to the magnification region of GTR), and the unsaturated region (corresponding to the saturation region of GTR). The MOSFET operates in the on-off state, that is, switching back and forth between the cut-off zone and the unsaturated zone. There are parasitic diodes between the drain and source, and the devices are on when a reverse voltage is added between the drain and source. The on-state resistance of the power MOSFET has a positive temperature coefficient, which is beneficial to the current sharing of the devices in parallel.   1. Cut-off Region: with the transistor acting as an open switch, the gate-source voltage is much lower than the transistor's threshold voltage so the MOSFET transistor is switched off fully.   2. Linear (Ohmic) Region: the transistor is in its constant resistance region behaving as a voltage-controlled resistance whose resistive value is determined by the gate voltage.   3. Saturation Region: the transistor is in its constant current region and is therefore switched on fully. The Drain current is equal to the maximum with the transistor acting as a closed switch.   Dynamic Properties   On-delay time (Td): it is the time experienced when the gate-source voltage rises to 10% of the gate drive voltage to the specified current rises to 10%.   Rise time (Tr): it is the time taken to increase the drain current from 10% to 90%. The ID steady-state value is determined by the drain-source voltage UE and the drain load resistance. The UGSP is related to the steady-state value of the ID, and when the UGS reaches the UGSP, it continued to increase until it reached the steady-state, but the ID did not change.   Turn-on time: the sum of turn-on delay time and rise time.   Turn-off delay time (Td): it refers to the time from when the voltage between gate and source drops to 90% of the gate drive voltage to the leakage current of 90% of the specified current. This shows the delay before the current is transferred to the load.    Drop time: it is the time experienced by the drain current drops from 90% to 10%.    Turn-off time: the sum of the turn-off delay time and drop time.   Understand several commonly used parameters of MOSFET. VDS is the drain-source voltage, which is an absolute parameter rating of MOSFET, which indicates the maximum voltage value that MOSFET can bear between drain and source. It is important to note that this parameter is related to junction temperature, and the higher the junction temperature is, the greater the value is. RDS (on), refers to the leakage source on-resistance, which represents the on-resistance between drain and source when MOSFET is on under certain conditions.    This parameter is related to MOSFET junction temperature and driving voltage Vgs. In a certain range, the higher the junction temperature, the greater the Rds, the higher the driving voltage, the smaller the Rds. Qg is the gate charge, gate charge is the charge required to increase the gate voltage from 0V to the termination voltage (such as 15V) under the action of the driving signal.   That is the charge required by the driving circuit from the cut-off state to the full-on state, which is the main parameter used to evaluate the driving ability of the driving circuit of the MOSFET. Id (drain current), is usually described in several different ways. According to the form of the working current, it divided into the continuous drain current and the pulse drain current.    In addition, it is also an absolute parameter rating of MOSFET, but this maximum current value does not mean that the drain current can reach this value during operation. It means that when the shell temperature is at a certain point if the operating current of MOSFET is the maximum drain current mentioned above, the junction temperature will reach the maximum value. Thus this parameter is also related to device packaging and ambient temperature.   Eoss (output volume energy), representing the output capacitance Coss stored in the MOSFET. Because the output capacitance Coss of MOSFET has very obvious nonlinear characteristics, it varies with the change of Vds voltage. If the datasheet identifies this parameter, it will be helpful to evaluate the switching loss of the MOSFET. The current rate of the body diode di/dt reflects the MOSFET reverse recovery characteristics. Because the diode is a bipolar device, it is affected by the charge storage, when the diode reverses bias, the charge stored in the PN junction must be removed, which is precisely the reaction of the above-mentioned parameters characteristic.   The maximum gate-source driving voltage Vgs, which is also an absolute parameter rating of the MOSFET, represents the maximum driving voltage that the MOSFET can withstand. Once the driving voltage exceeds this limit, permanent damage to the gate oxide can occur even in a very short period of time. Generally speaking, as long as the driving voltage does not exceed the limit, there will be no problem. However, due to the existence of parasitic parameters in some special cases, the Vgs will be affected unpredictably, which needs to be paid more attention to. SOA (safe work area), each MOSFET will give its safe working area. For example, different bipolar transistors, power MOSFET does not show a second breakdown, so the safe operation area is simply defined from the dissipative power that causes the junction temperature to reach the maximum allowable value.      II. MOSFET Selection   After understanding the principle of MOSFET selection, You can select the correct MOSFET with the following four steps.   1) channel selection The first step in choosing the right device for design is to decide whether to use N-channel or P-channel MOSFET. In typical power applications, when a MOSFET is grounded and the load is connected to the trunk voltage, the MOSFET forms a low-voltage side switch. N-channel MOSFET should be used in the low-voltage side switch, which is due to the voltage required by switching on or switching off the device. When the MOSFET is connected to the bus and the load is grounded, the high-voltage side switch is used. P-channel MOSFET is usually used in this case, which is also due to the consideration of driving voltage.   2) selection of voltage and current The higher the rated voltage, the higher the cost of the device. According to practical experience, the rated voltage should be greater than trunk voltage or bus voltage. This will provide sufficient protection so that the MOSFET can work well. As far as MOSFET is concerned, it is necessary to determine the maximum possible voltage between the drain and the source. Other safety factors that design engineers need to consider include voltage transients induced by switchgear, such as motors or transformers. And rated voltages vary from application to application, typically, portable devices are 20V, FPGA power supplies are 20V~30V, and so on.　   In the continuous conduction state, the MOSFET is stable and the current passes through the device continuously. A pulse spike refers to a large number of surge current (or peak current) flowing through the device. Once the maximum current is determined under these conditions, simply select the device that can withstand the maximum current.   3) calculating on-loss The power loss of MOSFET devices can be calculated by Iload2×RDS (on). Because the on-resistance varies with temperature, the power loss also varies proportionally. For portable designs, lower voltages are more common, and for industrial designs, higher voltages can be used. Note that the RDS (on) resistance increases slightly with the current. Variations in the electrical parameters of the RDS (on) resistance can be found in the technical datasheet provided by the manufacturer.   4) heat dissipation requirements for a computing system　 The designer must consider two different situations, the worst case, and the real situation. It is recommended that the worst-case results be used because the results provide a greater security margin to ensure that the system does not fail. There are also some measurements on the MOSFET table that need to be noticed, such as the thermal resistance between the semiconductor junction and the environment of the packaged device, and the maximum junction temperature.   Switching loss is also a very important indicator. The voltage-current product of the on-off moment is quite large, which determines the switching performance of the device to a certain extent. However, if the system requires high switching performance, you can choose a power MOSFET with a lower gate charge.     III. MOSFET Gate Material   Theoretically, the gate of MOSFET should be chosen as well as possible, and the conductivity of polysilicon doped by heavy can be used on the gate of MOSFET.    The reasons for using polysilicon in MOSFETs are as follows:    1) The threshold voltage of the MOSFET is mainly determined by the difference between the work function of the gate and the channel material, and because the polysilicon is essentially a semiconductor, it is possible to change its work function by doping impurities of different polarities. More importantly, since the gap between the polysilicon and the silicon as the channel is the same, it is possible to achieve the demand by directly adjusting the work function of the polysilicon when the threshold voltage of the PMOS or NMOS is reduced. Conversely, the work function of the metallic material is not like the semiconductor is then easily changed so that it becomes difficult to reduce the critical voltage of the MOSFET. And if the threshold voltage of the PMOS and the NMOS is to be reduced at the same time, two different metals are required to do their gate material, respectively, and a large variable for the producing process.   2) After years of research on the silicon-silica interface, it has been proved that the defect between the two materials is relatively small. On the contrary, there are many defects in the metal-insulator interface, so it is easy to form a lot of surface energy levels between the two, which greatly affects the characteristics of the elements.   3) The melting point of the polycrystalline silicon is higher than most of the metal, while in the modern semiconductor process, the gate material is used to deposit the gate material at high temperatures to improve the efficiency of the element. The low melting point of the metal will affect the upper-temperature limit that can be used by the process.   However, although polysilicon has been the standard material for the manufacture of MOSFET gates, there are also a number of shortcomings of it, which makes it possible for some MOSFET to use metal gates in the future.    These shortcomings are as follows:   (1) Polysilicon is less conductive than metal, limiting the speed of signal transmission. Although doping can be used to improve its conductivity, the effectiveness is still limited. Some metal materials with a high melting point, such as tungsten, titanium, cobalt, or nickel, are used to make alloys with polysilicon. This type of mixture is commonly referred to as metal silicide. The polysilicon gate with metal silicide has good electrical conductivity and can withstand a high-temperature process. In addition, because the position of the metal silicide is on the surface of the grid, therefore, the critical voltage of MOSFET will not be affected much.   The process of plating a metal silicide on the gate, source, and drain is referred to as self-aligned metal, commonly referred to as salicide process.   (2) When the size of the MOSFET is small and the gate oxide layer also becomes very thin, for example, the new process can reduce the oxide layer to a thickness of about one nanometer, and a phenomenon is also generated unprecedentedly, and that is "polysilicon depletion". When the inversion layer of the MOSFET is formed, the MOSFET gate polysilicon depletion phenomenon is occurring close to the oxide layer, and a depletion layer is present to influence the conduction characteristics of the MOSFET. To address this problem, one way is the metal gate. Reasonable materials include tantalum, tungsten, tantalum nitride, or titanlium nitride. The gates made by these metals usually form MOS capacitors along with oxide formed by high permittivity substances. Another solution is the polysilicon alloying, also called FUSI (FUlly-SIlicide polysilicon gate).   IV. MOSFET Advantage   MOSFET was first made successfully in 1960 by D. Kahng and Martin Atalla in Bell Labs, and the operating principle of this element was very different from that of the bipolar junction transistor (BJT) invented by William Shockley in 1947. And because of the low cost and small size, it plays a very important role in large-scale integrated circuits (LSI) and very large-scale integrated circuits (VLSI) than BJT.   1) Field-effect transistor (FET) is a voltage control element, and bipolar junction transistor (BJT) is a current control element. The FET should be selected when only less current is allowed, and the BJT should be chosen when the signal voltage is low and more current is allowed to flow through from the source of the signal.   2) The source and drain poles of some FET can be used interchangeably, the gate voltage can also be positive and negative, and the flexibility is better than the bipolar transistor.   3) FET is called a monopole device because it makes use of majority carriers to conduct electricity, while BJT is conducting by majority carrier or minority carrier, therefore, it is called bipolar device.   4) FET can work under the conditions of very low current and low voltage, and its manufacturing process can easily integrate many FETs on a silicon wafer. Therefore, FET has been widely used in large-scale integrated circuits (LSI).   With the improvement of the performance of MOSFET components, except the traditional applications in digital signal processing such as microprocessors and microcontrollers, more and more integrated circuits for analog signal processing can be implemented by MOSFET.   V. MOSFET Technology   1) Dual-gate MOSFET Dual-gate MOSFET is usually used in radio frequency (RF) integrated circuits. The two gates of the MOSFET can control the current. In RF circuits, the second gate of the dual-gate MOSFET is mostly used for gain, mixer, or frequency conversion control.   2) Depletion Type MOSFET In general, a depletion-mode MOSFET is less common than the enhancement mode MOSFET. The depletion-mode MOSFET changes the impurity concentration of the channel in the doping process so that the channel still exists even if the gate of the MOSFET is not applied voltage. If you want to close the channel, you must apply a negative voltage to the gate. Thus the most application of the depleted MOSFETs is in the "normally-off" switch, while the enhancement-mode MOSFET is usually used in the " normally-on" switch.   3) NMOS Logic The NMOS of the same driving capability is generally smaller than the area occupied by the PMOS, and therefore, if an NMOS is used only on the design of the logic gate, the chip area itself can be reduced. However, although the area of the NMOS logic is small, the static power will be consumed unlike the CMOS logic, so it has gradually exited the market after the mid-1980s.   4) Power MOSFET There is a significant structural difference between the power MOSFET and the above-mentioned MOSFET elements. In general, MOSFET in integrated circuits are planar structures, and the endpoints of transistors are only a few microns away from the surface of the chip. But all the power components are vertical structures, which allows the components to withstand both high voltage and high current working environments. A power MOSFET withstand voltage is a function of the doping concentration and the thickness of the N-type epitaxial layer, and the width of the channel is related to how much the current can pass through, that is, the wider channel can accommodate more current. For a planar MOSFET, the current and the breakdown voltage are dependent on the length and width of the channel. For a vertical MOSFET, the area of the element is approximately proportional to the current it can hold, and the thickness of the epitaxial layer is proportional to its breakdown voltage.   Working principle Due to the positive power supply between the source and the drain, the voltage between them is zero. The PN junction J1 formed between the P base region and the N drift region is anti-biased, and no current flows between the source and the drain.   Conduction: the positive voltage UGS, the gate is insulated between the gate and the source, so there will be no gate current flowing through. However, when the positive voltage of the gate pushes the hole in the P region below it and attracts the minority electron in the P region to the surface of the P region below the gate and the UGS is greater than the UT (on voltage or threshold voltage), the electron concentration on the surface of the P region under the gate will exceed the hole concentration, which causes the P-type semiconductor inversion to become N-type and becomes the inversion layer. The inversion layer forms N-channel and makes the PN junction J1 disappear, and the drain and the source turn to conductive.   It is worth mentioning that power MOSFET with planar structure is not non-existent, and this kind of element is mainly used in advanced sound amplifiers. The characteristics of planar power MOSFET in the saturation region are better than that of vertical structure MOSFET. Vertical power MOSFET takes the advantage of very small turn-on resistance and is mostly used for switches.   5) DMOS DMOS is an abbreviation for a double-diffused MOSFET, which is mainly used for high voltage and belongs to the category of high-voltage MOSFET.   The MOSFET is used to realize the analog switch. The channel resistance of the MOSFET is low when the MOSFET is turned on, and the resistance is almost infinite when the MOSFET is turned off so that the switch which is suitable as a switch of the analog signal (the energy of the signal is not lost due to the resistance of the switch). When the MOSFET is a switch, its source and drain are different from each other, respectively, because the signal can be accessed from any end of the MOSFET. For an NMOS switch, the negative voltage is in the source, it opposite to the PMOS, the positive voltage is in the source. The signal that the MOSFET switch can transmit is subject to its voltage between gate and source, gate and drain, drain and source. If the upper limit of the voltage is exceeded, the MOSFET may burn out.   MOSFET switches have a wide range of applications, such as the need for sampling holding circuit (sample-and-hold circuits) or truncated circuit (chopper circuits) design, For example, MOSFET switch can be seen on the analog-digital converter (A / D converter) or switched capacitor filter (switch-capacitor filter).   6) Single MOSFET Switch When the NMOS is used as a switch, the base is grounded and the gate is the controlling end of the switch. The state of the switch is on when the gate voltage subtracts the source voltage exceeding the critical voltage. If the gate voltage continues to rise, the current through which the NMOS can pass more. NMOs operate in the linear region when the switch is turned on because the voltage of the source and drain tends to be consistent when the switch is on.   When the PMOS is used as a switch, its base is connected to the highest potential in the circuit, usually a power supply. The voltage of the gate is very low than the source. And when the gate exceeds the critical voltage, the PMOS switch will be turned on.   And a single MOSFET switch may reduce the amplitude of the signal and distort the signal.   7) Double MOSFET (CMOS) Switch In order to improve the signal distortion caused by the single MOSFET switch mentioned above, the use of a PMOS plus and an NMOS of CMOS switch has become the most common practice at present. The PMOS switch connects the source and drain of the NMOS separately. The basic joining rule is the same as the traditional connecting method of NMOS and PMOS. When the input voltage is at (VDD-Vthn) and (VSS+Vthp), the PMOS and NMOS are on, but when the input is less than (VSS+Vthp), only NMOS is on and the input is greater than (VDD-Vthn), and only the PMOS turns on. The advantage of this is that under most of the input voltage, both the PMOS and the NMOS are turned on at the same time, and if the on-resistance of either side is increased, the on-resistance on the other side is reduced, so that the resistance of the switch can be kept almost constant, thus the signal distortion is reduced.   Fig. 8 switching process of power MOSFET   VI. Common MOSFET Failures     Overvoltage damage, including gate overvoltage and drain overvoltage, often accompanied by overcurrent. If protection happened in a very short period of time, it may be overvoltage damage. If there is no overvoltage protection and the state turns into overcurrent damage, the chip in the source non-line region will burn out.   A large current, such as severe over-current short-circuit damage, will cause a large amount of heat to burn out the chip.   Overheat damage, if the MOS tube isn’t appearing overcurrent and overvoltage, just because the junction temperature is too high, if the chip is protected, the surface will not see obvious burns, if not, there will be a large amount of burning area.   In general, the mechanism of MOS tube damage is usually thermal damage, local overheating, or overall heating, such as overvoltage, is a crystal package that can’t stand high voltage breakdown causing heating damage.   The fault analysis of the MOS tube should be based on the combination of specific circuit and burning phenomenon to be more accurate. Fig. 9 basic structure of an n-channel mosfet     VII. MOSFET's Well-Known Brands   MOSFETs are mainly divided into several series: American, Japanese, Korean, Taiwan, and so on. The brand's representatives of each system are as follows:   American: IR ST TI PI Fairchild Infineon ON Semiconductor Japanese: TOSHIBA RENESAS SHINDENGEN Taiwan: APEC CET Korean: KEC AUK MagnaChip KIA Truesemi Wisdom   FAQ 1. What is Mosfet and how it works? In general, the MOSFET works as a switch, the MOSFET controls the voltage and current flow between the source and drain. The working of the MOSFET depends on the MOS capacitor, which is the semiconductor surface below the oxide layers between the source and drain terminal.   2. What is Mosfet and its characteristics? MOSFETs are tri-terminal, unipolar, voltage-controlled, high input impedance devices which form an integral part of vast variety of electronic circuits. ... In this region, MOSFET behaves like an open switch and is thus used when they are required to function as electronic switches.   3. How many types of Mosfet are there? Four types. There are two classes of MOSFETs. There is depletion mode and there is enhancement mode. Each class is available as n- or a p-channel, giving a total of four types of MOSFETs.   4. What is an ideal Mosfet? In an ideal MOSFET, setting the gate-source voltage to a value VGS < VTn places the transistor into cutoff with ID = O. Increasing the gate-source voltage to a value VGS > VTn allows the transistor to conduct current ID; this defines the active mode of operation. 5. How do I know if my MosFet is bad? A good MOSFET should have a reading of 0.4V to 0.9V (depends on the MOSFET type). If the reading is zero, the MOSFET is defective and when the reading is “open” or no reading, the MOSFET is also defective. When you reverse the DMM probe connections, the reading should be “open” or no reading for a good MOSFET.   6. What is a Mosfet used for? What is a MOSFET and How does it work? MOSFET, in short, is a metal oxide semiconductor field-effect transistor used to switch or amplify voltages in circuits. Being part of the field-effect transistor family, it is a current-controlled device that is constructed with 3 terminals.   7. Is Mosfet still used? The MOSFET is by far the most widely used transistor in both digital circuits and analog circuits, and it is the backbone of modern electronics. It is the basis for numerous modern technologies, and is commonly used for a wide range of applications.   8. Why is it called Mosfet? The source is so named because it is the source of the charge carriers (electrons for n-channel, holes for p-channel) that flow through the channel; similarly, the drain is where the charge carriers leave the channel.   9. What causes a Mosfet to fail? If the maximum operating voltage of a MOSFET is exceeded, it goes into Avalanche breakdown. ... If the energy contained in the transient over-voltage is above the rated Avalanche energy level, then the MOSFET will fail. The device fails short circuit, initially, with no externally visible signs.   10. Why N channel is better than P channel Mosfet? N-Channel MOSFETs are more efficient than P-Channel MOSFETs.It comes down to physics. N-Channel MOSFETs use electron flow as the charge carrier. P-Channel MOSFETs use hole flow as the charge carrier, which has less mobility than electron flow. And therefore, they have higher resistance and are less efficient.   You May Also Like Selection of Drive Resistor: MOSFET | Gate Drive Reference Component KY56-SQ7415AEN-T1_GE3 KY56-STP160N3LL

Use of copper as a fluorescent material allows for the manufacture of inexpensive and environmentally compatible organic light-emitting diodes (OLEDs). Thermally activated delayed fuorescence (TADF) ensures high light yield. Scientists of Karlsruhe Institute of Technology (KIT), CYNORA, and the University of St Andrews have now measured the underlying quantum mechanics phenomenon of intersystem crossing in a copper complex. The results of this fundamental work are reported in the Science Advances journal and contribute to enhancing the energy efficiency of OLEDs.  Organic light-emitting diodes are deemed tomorrow's source of light. They homogeneously emit light in all observation directions and produce brilliant colors and high contrasts. As it is also possible to manufacture transparent and flexible OLEDs, new application and design options result, such as flat light sources on window panes or displays that can be rolled up. OLEDs consist of ultra-thin layers of organic materials, which serve as emitter and are located between two electrodes. When voltage is applied, electrons from the cathode and holes (positive charges) from the anode are injected into the emitter, where they form electron-hole pairs. These so-called excitons are quasiparticles in the excited state. When they decay into their initial state again, they release energy.Excitons may assume two different states: Singlet excitons decay immediately and emit light, whereas triplet excitons release their energy in the form of heat. Usually, 25 percent singlets and 75 percent triplets are encountered in OLEDs. To enhance energy efficiency of an OLED, also triplet excitons have to be used to generate light. In conventional light-emitting diodes heavy metals, such as iridium and platinum, are added for this purpose. But these materials are expensive, have a limited availability, and require complex OLED production methods.It is cheaper and environmentally more compatible to use copper complexes as emitter materials. Thermally activated delayed fluorescence (TADF) ensures high light yields and, hence, high efficiency: Triplet excitons are transformed into singlet excitons which then emit photons. TADF is based on the quantum mechanics phenomenon of intersystem crossing (ISC), a transition from one electronic excitation state to another one of changed multiplicity, i.e. from singlet to triplet or vice versa. In organic molecules, this process is determined by spin-orbit coupling. This is the interaction of the orbital angular momentum of an electron in an atom with the spin of the electron. In this way, all excitons, triplets and singlets, can be used for the generation of light. With TADF, copper luminescent material reaches an efficiency of 100 percent.Stefan Bräse and Larissa Bergmann of KIT's Institute of Organic Chemistry (IOC), in cooperation with researchers of the OLED technology company CYNORA and the University of St Andrews, United Kingdom, for the first time measured the speed of intersystem crossing in a highly luminescent, thermally activated delayed fluorescence copper(I) complex in the solid state. The results are reported in the Science Advances journal. The scientists determined a time constant of intersystem crossing from singlet to triplet of 27 picoseconds (27 trillionths of a second). The reverse process – reverse intersystem crossing – from triplet to singlet is slower and leads to a TADF lasting for an average of 11.5 microseconds. These measurements improve the understanding of mechanisms leading to TADF and facilitate the specific development of TADF materials for energy-efficient OLEDs.Reference:KY59-0202NYKY59-S101D2LCD-S301C31TR 

This comprehensive article introduces crystal oscillators in detail, covering what this component is, how it works, the various types of crystal oscillators available, and how to select the most suitable crystal oscillator for your project.I What is a Crystal Oscillator?This video explains the working and design principles of crystal oscillators, providing valuable insights for students and engineers in understanding the operational mechanisms and design considerations.A crystal oscillator is a type of electronic oscillator that utilizes the mechanical resonance of a vibrating crystal made from piezoelectric material to generate an electrical signal with a precise frequency. Typically, a wafer is cut from a quartz crystal at a specific orientation angle and combined with integrated circuits to form an oscillating circuit within a package.As mentioned above, the resonator plate can be cut from the source crystal at different angles. The cutting method significantly influences the crystal's aging characteristics, frequency stability, thermal properties, and other parameters. Most cuts are made for bulk acoustic wave (BAW) operation, while surface acoustic wave (SAW) devices are employed for higher frequencies.2025 Update: Modern crystal oscillators now commonly operate at frequencies up to several GHz, with advanced MEMS-based oscillators becoming increasingly popular for their improved shock resistance and faster startup times.Crystal Cut Types and SpecificationsCutFrequency RangeModeAnglesDescriptionAT0.5–300MHzthickness shear (c-mode, slow quasi-shear)35°15', 0° (<25 MHz)35°18', 0°(>10 MHz)The most common cut. The plate contains the crystal's x axis and is inclined by 35°15' from the z (optic) axis. The frequency-temperature curve is sine-shaped with inflection point around 25–35°C. Has frequency constant 1.661MHz·mm.SC0.5–200MHzthickness shear35°15', 21°54'A double-rotated cut (35°15' and 21°54') for oven-stabilized oscillators with superior temperature stability.BT0.5–200MHzthickness shear (b-mode, fast quasi-shear)−49°8', 0°A special cut similar to AT cut with different temperature characteristics.ITVariousthickness shearOptimized anglesA double-rotated cut with improved characteristics for oven-stabilized oscillators.XY (tuning fork)3–85kHzlength-width flexureStandard orientationSmaller than other low-frequency cuts, less expensive, has low impedance and low Co/C1 ratio. Chief application is the 32.768 kHz RTC crystal.Crystal Oscillator Key Features:High Stability: Crystal oscillators are used in applications requiring very stable frequency references.Superior Performance: Unlike LC and RC oscillators, crystal oscillator frequency changes minimally with temperature, supply voltage, or component value variations.Excellent Selectivity: Provides very good selectivity due to high Q-factor (Quality Factor).Working Principle of Crystal Oscillator:The crystal oscillator operates on the principle of the inverse piezoelectric effect. When an alternating voltage is applied to a properly cut and mounted quartz crystal, it produces mechanical vibrations at its resonant frequency.Equivalent Circuit of Crystal:The crystal can be represented as an RLC circuit in its electrical equivalent. It has two resonant frequencies:1) Series Resonant Frequency (fs)2) Parallel Resonant Frequency (fp)The RLC circuit provides frequency selectivity for oscillation, and when combined with an amplifier, creates a complete oscillator circuit.II Crystal Oscillator Operational PrincipleA crystal is a solid material consisting of atoms, molecules, or ions arranged in a regularly ordered, repeating pattern extending in all three spatial dimensions.Any object made of elastic material can potentially serve as a resonator with appropriate transducers, as all objects have natural resonant frequencies. For example, steel was often used in mechanical filters before quartz became prevalent due to its elasticity and high speed of sound propagation.When a quartz crystal is properly cut and mounted, it can be made to deform in an electric field by applying voltage to electrodes. This property is known as the piezoelectric effect. When alternating voltage is applied, the crystal produces mechanical vibrations, which in turn generate an alternating electric field.The quartz crystal oscillator can be electrically modeled as a two-terminal network with a capacitor and resistor in parallel, plus a capacitor in series. This network has two resonance points: the lower frequency (series resonance) and the higher frequency (parallel resonance).Due to the crystal's inherent characteristics, these two frequencies are very close. Within this narrow frequency range, the crystal oscillator behaves like an inductor, forming a parallel resonant circuit when appropriate capacitors are connected.Important Note: Load capacitance is a critical parameter. Selecting a parallel capacitor matching the crystal's load capacitance specification ensures operation at the nominal resonant frequency.Key Performance Parameters:(1) Total Frequency Tolerance: The maximum frequency deviation from the nominal frequency caused by all specified operating and non-operating parameters within a specified time period.(2) Frequency Temperature Stability: The maximum allowable frequency deviation over a specified temperature range under nominal power supply and load conditions.fT = ±(fmax-fmin)/(fmax+fmin)fTref = ±max[|(fmax-fref)/fref|，|(fmin-fref)/fref|](3) Frequency Aging Rate: The relationship between oscillator frequency and time under constant ambient conditions, typically specified as ±10ppb/day after 72 hours of operation.(4) Phase Noise: The ratio of power density in phase-modulated sidebands to carrier power at a specified offset frequency from the carrier.III Crystal Oscillator ParametersFrequency Accuracy: The maximum allowable deviation between the oscillator frequency and its nominal value under specified conditions, expressed as (fmax-fmin)/f0.Temperature Stability: The allowable frequency variation over the specified temperature range, calculated as (fmax-fmin)/(fmax+fmin).Frequency Tuning Range: The range of output frequencies achievable by adjusting variable elements in the crystal oscillator circuit.Voltage-Controlled Characteristics: For VCXOs, this includes:FM Deviation: Output frequency difference when control voltage varies from maximum to minimumFM Sensitivity: Frequency change per unit control voltage changeFM Linearity: Measure of linearity compared to ideal straight-line responseLoad Characteristics: Maximum frequency deviation due to load impedance variations within specified ranges.Supply Voltage Characteristics: Maximum frequency deviation due to supply voltage variations within specified ranges.Spurious Signals: Power ratio of discrete spectral components to the main frequency, excluding harmonics, expressed in dBc.Harmonics: Ratio of harmonic component power to carrier power, expressed in dBc.Frequency Aging: Systematic frequency drift over time due to component aging, particularly the quartz resonator.Daily Stability: Frequency variation measured over 24 hours after specified warm-up time.Startup Characteristics: Maximum frequency change within specified warm-up time, expressed as V = (fmax-fmin)/f0.Phase Noise: Frequency domain representation of rapid, short-term, random phase fluctuations caused by time domain instabilities.IV. Crystal Oscillator Frequency Stability & Input/OutputFrequency StabilityFrequency stability over operating temperature is one of the primary characteristics determining oscillator cost. Higher stability requirements or wider temperature ranges result in higher device costs.Crystal aging is a significant factor in long-term frequency stability. The aging rate follows a logarithmic curve and is most pronounced during the first year of operation. For applications requiring 10+ year operation, the aging rate is approximately three times that of the first year.2025 Update: Modern crystal oscillators now achieve aging rates as low as ±0.1 ppb/day for high-end OCXO units, and MEMS oscillators offer improved aging characteristics compared to traditional quartz devices.Other factors affecting frequency stability include supply voltage variations, load changes, phase noise, jitter, and electromagnetic interference (EMI). For industrial applications, vibration and shock specifications are critical, while aerospace applications require tolerance specifications for pressure changes and radiation exposure.Output TypesCrystal oscillators are available with various output types compatible with different logic families:HCMOS/TTL: Most common for digital applicationsACMOS: Low power applicationsECL: High-speed applicationsLVDS: High-speed differential signalingHCSL: High-speed current steering logicSine Wave: Analog applications requiring pure sinusoidal outputCritical specifications include symmetry (typically 45%-55%), rise/fall times (often <5ns for high-speed applications), and logic levels. Many DSP and communication chipsets require strict symmetry and fast edge rates.Phase Noise and JitterPhase noise, measured in the frequency domain, represents true short-term stability. It's typically measured from 1Hz to 1MHz offset from the carrier frequency. Crystal oscillators using fundamental or harmonic modes provide the best phase noise performance, while PLL-based synthesized oscillators generally exhibit poorer phase noise characteristics.Jitter, related to phase noise but measured in the time domain, is specified in picoseconds (RMS or peak-to-peak). Applications such as communication networks, wireless data transmission, ATM, and SONET require careful attention to both characteristics.V Crystal Oscillator ApplicationsCrystal oscillators serve as precision clock sources in microcontroller systems and can be categorized into two main types:Mechanical resonance devices: Crystal oscillators and ceramic resonators (suitable for Pierce oscillator configurations)RC oscillators: Lower cost but less accurate alternativesCrystal oscillators and ceramic resonators provide high initial accuracy and low temperature coefficients. RC oscillators offer quick startup and lower cost but typically achieve only 5%-50% accuracy over temperature and supply voltage ranges.Environmental ConsiderationsEnvironmental factors affecting oscillator performance include:Electromagnetic Interference (EMI)Mechanical vibration and shockHumidityTemperature variationsSupply voltage fluctuationsThese factors can cause frequency instability and, in severe cases, oscillator failure. Oscillator modules help mitigate many of these issues by providing complete, tested solutions with specified environmental tolerances.Power Consumption ConsiderationsPower consumption varies significantly by oscillator type:Discrete crystal circuits: 1-5mA typicalCrystal oscillator modules: 10-60mA typicalMEMS oscillators: 1-50mA depending on frequency and featuresUltra-low power oscillators: <1mA for battery-powered applicationsCommon ApplicationsGeneral oscillating circuits for frequency generationDigital clock generation for processors and microcontrollersMicroprocessor timing referencesConsumer electronics (TV, VCR, DVD players)Timekeeping applications (watches, clocks, RTCs)Communication systems (cellular, WiFi, Bluetooth)Test and measurement equipmentAutomotive electronicsIndustrial control systemsVI Crystal Oscillator TypesCrystal oscillators are classified into several categories based on their design and application requirements:By Temperature Compensation Method:TCXO: Temperature-Compensated Crystal OscillatorVCXO: Voltage-Controlled Crystal OscillatorOCXO: Oven-Controlled Crystal OscillatorDCXO: Digitally Compensated Crystal OscillatorMCXO: Microcomputer-Compensated Crystal OscillatorBy Circuit Configuration:Passive Crystal Oscillators: Require external oscillator circuitActive Crystal Oscillators: Complete oscillator with built-in amplificationBy Package Type:Metal Can: Traditional hermetic sealingCeramic: Good thermal propertiesPlastic: Cost-effective for commercial applicationsSMD: Surface mount for automated assemblyCommon Types and AbbreviationsAbbreviationFull NameTypical StabilityTCXOTemperature-Compensated Crystal Oscillator±0.1 to ±2.5 ppmVCXOVoltage-Controlled Crystal Oscillator±25 to ±100 ppmOCXOOven-Controlled Crystal Oscillator±0.001 to ±0.1 ppmDCXODigitally Compensated Crystal Oscillator±0.1 to ±1 ppmMCXOMicrocomputer-Compensated Crystal Oscillator±0.05 to ±0.5 ppmGPSDOGPS Disciplined Oscillator±0.001 ppmMEMSMicro-Electro-Mechanical Systems Oscillator±20 to ±100 ppm2025 Update: MEMS oscillators have gained significant market share due to their superior shock/vibration resistance, faster startup times, and programmability. They're increasingly used in automotive and IoT applications.Active vs. Passive Crystal OscillatorsPassive Crystal Oscillators:Require external oscillator circuit in the CPU/MCUTwo-pin, non-polar componentSignal level determined by the driving circuitCan work with various supply voltagesLower costRequire careful PCB layout and component matchingActive Crystal Oscillators:Complete oscillator with built-in amplificationFour-pin device with power supply connectionsFixed output signal levelBetter signal quality and stabilitySimpler connection (typically requires only power supply filtering)Higher cost but more reliable operationAvailable in various output formats (CMOS, TTL, LVDS, etc.)VII Crystal Oscillator Selection GuideSelecting the appropriate crystal oscillator requires careful consideration of application requirements and environmental conditions.Selection Criteria by Stability Requirements:±100 ppm or less: Standard XO or VCXO±5 to ±25 ppm: TCXO±0.5 to ±5 ppm: High-grade TCXO or ATCXO±0.1 to ±0.5 ppm: MCXO or DCXO±0.01 to ±0.1 ppm: OCXOBetter than ±0.01 ppm: GPSDO or atomic referenceApplication-Specific Considerations:Communication Systems:Cellular base stations: OCXO or high-grade TCXOMobile devices: TCXO with voltage controlWiFi/Bluetooth: Standard TCXOSatellite communication: OCXO with GPS discipliningComputing and Digital Systems:Microprocessors: Standard XO or TCXOHigh-speed processors: Low-jitter TCXO or MEMSReal-time clocks: 32.768 kHz tuning fork crystalsNetwork equipment: Low-jitter TCXO or OCXOTest and Measurement:Frequency counters: OCXOSignal generators: OCXO with low phase noiseOscilloscopes: Low-jitter TCXOSpectrum analyzers: Ultra-low phase noise OCXOEnvironmental Considerations:Temperature Range:Commercial (0°C to +70°C): Standard gradesIndustrial (-40°C to +85°C): Industrial gradesMilitary (-55°C to +125°C): Military-grade devicesAutomotive (-40°C to +125°C): AEC-Q100 qualifiedMechanical Environment:High vibration: MEMS oscillators or ruggedized crystalsShock resistance: MEMS or specially mounted crystalsSize constraints: Ultra-miniature packages (1.6×1.2mm or smaller)Power Consumption Optimization:Battery-powered devices: Ultra-low power TCXO or MEMSAlways-on applications: Low standby current oscillatorsPortable devices: Programmable MEMS with power-down modesPackage Selection:Through-hole: Traditional DIP packages for prototypingSurface mount: Various sizes from 7×5mm to 1.6×1.2mmUltra-miniature: Wafer-level chip scale packages (WLCSP)Development Trends (2025):Miniaturization: Continued reduction in package sizesIntegration: Multi-frequency and programmable outputsMEMS adoption: Replacing quartz in many applicationsIoT optimization: Ultra-low power and wireless-friendly designs5G/6G requirements: Ultra-low jitter and phase noiseAutomotive growth: AEC-Q100 qualified devices for ADAS and autonomous vehiclesTesting and Quality Assurance:Common crystal oscillator failure modes include:Internal leakage: Contamination or seal failureOpen circuit: Wire bond or connection failureFrequency drift: Aging or temperature effectsExternal component failure: Load capacitor issuesTesting Methods:1) Resistance Measurement: Use multimeter on high resistance range. Normal crystals should show infinite resistance in both directions. Any finite resistance indicates leakage or breakdown.2) Capacitance Measurement: Measure crystal capacitance using LCR meter or digital multimeter with capacitance function. Compare with expected values for the crystal type.3) Oscillation Test: Build simple test oscillator circuit to verify crystal functionality. Successful oscillation indicates good crystal condition.4) Frequency Accuracy Test: Use frequency counter to verify output frequency matches specification within tolerance.5) Temperature Testing: Verify frequency stability over specified temperature range.Recent Industry DevelopmentsIndustry Update: Leading manufacturers continue to push the boundaries of crystal oscillator performance. Recent developments include:Ultra-low jitter differential output oscillators achieving 65 fs phase jitterHigh-frequency fundamental (HFF) AT-cut crystals using advanced QMEMS processesImproved reliability compared to traditional 3rd overtone crystalsSupport for multiple differential output formats (HCSL, LVDS) in compact packagesEnhanced temperature stability for 5G and high-speed networking applicationsThe SG7050EBN series represents the latest advancement in differential-output crystal oscillators, operating from 100 MHz to 175 MHz with exceptional 65 fs phase jitter performance. This makes it suitable for 10-, 40-, and 100-Gigabit Ethernet applications in datacenters and telecommunications infrastructure.Frequently Asked Questions (FAQ)1. What is a crystal oscillator used for?A crystal oscillator is an electronic circuit that uses the mechanical resonance of a vibrating piezoelectric crystal to create an electrical signal with a precise frequency. It's used for timing references, clock generation, frequency synthesis, and signal processing applications.2. What are the advantages of crystal oscillators?Crystal oscillators offer very high frequency stability, precise and stable frequency generation, high Q-factor, low frequency drift with temperature and parameter changes, and excellent long-term stability compared to other oscillator types.3. What is the difference between a crystal and an oscillator?A crystal is the piezoelectric resonator element itself, while an oscillator is the complete circuit including the crystal, amplifier, and supporting components. The crystal provides the frequency reference, while the oscillator circuit sustains oscillation.4. How does a crystal oscillator work?The crystal oscillator circuit sustains oscillation by taking a voltage signal from the quartz resonator, amplifying it, and feeding it back to the resonator. The rate of expansion and contraction of the quartz determines the resonant frequency, based on the crystal's cut and size.5. What is the principle of oscillation?Electronic oscillators operate on the principle of positive feedback: a sensitive amplifier's output is fed back to the input in phase, causing the signal to regenerate and sustain itself through continuous positive feedback.6. What is the main feature of crystal oscillators?The most important feature is frequency stability - the ability to provide a constant frequency output under varying load conditions, temperature changes, and aging effects over long periods.7. Why is quartz crystal commonly used?Quartz is preferred due to its availability, mechanical strength, chemical stability, low cost, excellent piezoelectric properties, and predictable temperature characteristics. It also has a high Q-factor and good aging characteristics.8. Why are crystal oscillators more stable?Crystal oscillators are more stable because the mechanical resonance of quartz is highly stable and only minimally influenced by external factors like temperature, voltage, or component variations, unlike LC or RC oscillators.9. How do you test a crystal oscillator?Test methods include resistance measurement (should be infinite), capacitance measurement (compare to specifications), oscillation testing (build test circuit), and frequency accuracy verification using a frequency counter.10. Why are crystals used in microcontrollers?Crystal oscillators provide the precise clock signals required for microcontroller synchronization, ensuring accurate timing for instruction execution, peripheral operations, and communication protocols.11. Do crystal oscillators have polarity?Passive crystals (2-pin) have no polarity and can be connected in either direction. Active crystal oscillators (4-pin) have specific pin assignments for power, ground, and output that must be observed.12. Do crystal oscillators fail?Yes, crystal oscillators can fail due to mechanical shock, overheating beyond the Curie temperature, contamination, aging, or electrical overstress. However, they are generally very reliable components when properly used.13. Can crystals oscillate at multiple frequencies?Yes, crystals can oscillate at overtones (odd multiples of the fundamental frequency), but these are typically weaker than the fundamental. Circuits can be designed to operate crystals at their 3rd or 5th overtones.14. Why are oscillators used in electronic systems?Oscillators convert DC power to AC signals, providing timing references, clock signals, carrier frequencies for communication, and synchronization signals essential for digital and analog electronic systems.15. Why were crystal oscillators important for radio transmitters?Crystal oscillators provided the frequency stability needed for radio transmitters to maintain their assigned frequencies, preventing interference with other stations and ensuring reliable communication. They became standard in AM radio by 1926.Reference ComponentsLatest High-Performance Crystal Oscillators:SG7050EBN 125.000000M-DJGA3 - Ultra-low jitter differential oscillatorSG7050EBN 125.000000M-CJGA3 - High-frequency networking applicationsSG7050EBN 100.000000M-CJGA3 - 100 MHz precision referenceDisclaimer: This article has been updated for 2025 to reflect current technology trends and specifications. 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A new semiconductor device capable of emitting two distinct colours has been created by a group of researchers in the US, potentially opening up the possibility of using light emitting diodes (LEDs) universally for cheap and efficient lighting.The proof-of-concept device takes advantage of the latest nano-scale materials and processes to emit green and red light separated by a wavelength of 97 nanometres—a significantly larger bandwidth than a traditional semiconductor.Furthermore, the device is much more energy efficient than traditional LEDs as the colours are emitted as lasers, meaning they emit a very sharp and specific spectral line—narrower than a fraction of a nanometre—compared to LEDs which emit colours in a broad bandwidth.One of the main properties of semiconductors is that they emit light in a certain wavelength range, which has resulted in their widespread use in LEDs. The wavelength range in which a given semiconductor can emit light—also known as its bandwidth—is typically limited in the range of just tens of nanometres. For many applications such as lighting and illumination, the wavelength range needs to be over the entire visible spectrum and thus have a bandwidth of 300 nm.Single semiconductor devices cannot emit across the entire visible spectrum and therefore need to be 'put' together to form a collection that can cover the entire range. This is very expensive and is, to a large extent, the reason why semiconductor LEDs are not yet used universally for lighting.In this study, the researchers, from Arizona State University, used a process known as chemical vapour deposition to create a 41 micrometer-long nanosheet made from Cadmium Sulphide and Cadmium Selenide powders, using silicon as a substrate.Lead author of the study, Professor Cun-Zheng Ning, said: "Semiconductors are traditionally 'grown' together layer-by- layer, on an atom-scale, using the so-called epitaxial growth of crystals. Since different semiconductor crystals typically have different lattice constants, layer-by-layer growth of different semiconductors will cause defects, stress, and ultimately bad crystals, killing light emission properties."It is because of this that current LEDs cannot have different semiconductors within them to generate red, green and blue colours for lighting.However, recent developments in the field of nanotechnology mean that structures such as nanowires, nanobelts and nanosheets can be grown to tolerate much larger mismatches of lattice structures, and thus allow very different semiconductors to grow together without too many defects."Multi-colour light emission from a single nanowire or nanobelt has been realized in the past but what is important in our paper is that we realized lasers at two distinct colours. To physically 'put' together several lasers of different colors is too costly to be useful and thus our proof-of concept experiment becomes interesting and potentially important technologically."In addition to being used for solid state lighting and full color displays, such technology can also be used as light sources for fluorescence bio and chemical detection," continued Professor Ning.