difference between qfp and lqfp package difference between qfp and lqfp package

Battery configurations (series and parallel) and their protections, Electromagnetic & Radio Frequency Interference, Renesas and AMD to demo digital front-end design for 5G active antenna systems, STMicroelectronics expands STM32U5 series for IoT and embedded applications, Renesas offers advanced wireless power transmitter technology. However that doesn't mean that all QFP or TQFP packages are the same. Pins are numbered counter-clockwise from the index dot. The most common pin counts are four, six, eight, fourteen, eighteen, twenty, twenty-eight, and forty pins. QFP (Quad Flat Package) Definition. In this article, we will discuss some basics of IC packaging and the common IC packages. A package with metric pin distribution (0.50.8mm pitch), Micro surface-mount device extended technology, Earliest version metal/ceramic packaging with flat leads, No-leads, with exposed die-pad[s] for heatsinking, Heat-sink very-thin quad flat-pack, no-leads, IC packaged in transparent packaging used in optical sensor, Thermally-enhanced shrink small-outline package, Thermally-enhanced thin shrink small-outline package, Also referred as MSOP = micro small-outline package, Very-very-thin small-outline no-lead package, Bare silicon chip, an early chip-scale package, Package size is no more than 1.2 the size of the silicon chip. These increasingly small sizes, especially 0201 and 01005, can sometimes be a challenge from a manufacturability or reliability perspective. BGA packages are found on pcDuino and Raspberry Pi boards. . Used by LCD and OLED driver ICs. One for all standardized land pattern v.s. On January 27, 2003, the European Union passed the "Restriction on Use of Hazardous Substances in Electrical and Electronic Equipment," or "RoHS" legislation 2002/95/EC, which became effective July 1, 2006. The first step of the QFN-PCB assembly process has got to be solder printing. Read more about cookies. Why zero amount transaction outputs are kept in Bitcoin Core chainstate database? Polybrominated biphenyls (PBB): 0.1% (1000ppm), 6. So follow along and let us help you make a wise IC choice with all the facts in place, no more gambles! QFP pins are pretty small, plus they have small spacings. CERQUAD packages are the "low cost" alternative for CQFP packages, and are mainly used for terrestrial applications. The common quadruple inline packages are QIP/QIL (Quad In-line) and QUIP (ceramic leadless QIP). There's a standard IPC-7351A which describes method to design land patters. The following guide hopes to answer these questions. Yes: fully compliant to EU RoHS, no exemption required, Exempt: fully compliant to EU RoHS, with an exemption applied, RoHS restricted substances ppm calculation. MathJax reference. DPAK (TO-252, SOT-428): Discrete Packaging. These are surface-mounted packages with the leads extended out to the four sides of the package. LQFP. The REACH SVHC list is usually updated 2 times per year and the REACH Annex XVII list updated as needed. Such wire may then be covered with cotton, glass or other materials to make into smart textiles or electronic textiles. usado somente em SMT, no possvel o uso de soquetes ou thru-holes. It does not have any lid, plus it is only composed of two sections: However, these QFNs applications lie in the range of 2 to 3 GHz. These packages are hermetic. The terminals are either J-leaded or leadless. Board Assembly Recommendations (QFP) Share. Generally, large-scale or ultra-large-scale integrated circuits use this type of packaging. The LQFP comes in different body sizes, with lead counts ranging from 48 to 216. If you have any questions, you can feel free to contact me! These package types have two rows of terminals and a surface-mount mounting style. They hence become less robust whenever they experience some nominal CM or OEM practices. . Normal QFPs, on the other hand, utilize imperial measurements. Dibutyl phthalate (DBP): 0.1% (1000ppm), 10. BT resin, ceramic and polyimide resin carrier contains original components with higher cost while QFP contains plastic molding resin and metal sheet lead frame with low cost. One of them is the bonding diagram that shows the connectivity between the die and the package pads. Thermal & mechanical simulation results were performed to prove its advantage over conventional LQFP and LQFP_EP. Chip on board is a packaging technique that directly connects a die to a PCB, without an interposer or lead frame. The component has leads that are soldered to pads on the PCB to electrically and mechanically connect them to the PCB. We hope this article has shed light upon any questions you might have had regarding QFPs and QFNs and their differences. The common quadruple inline packages are QIP/QIL (Quad In-line) and QUIP (ceramic leadless QIP). Pitch: 0.4-0.8mm Figure 3. However, you still need to place the component carefully. System-in-Package (SiP) Solutions; LIN Functional Safety; Back; Browse USB; Basic USB Concepts and FAQs; USB Hubs; USB-C Power Delivery Controllers; USB Bridge Controllers; USB Switches and Transceivers; USB Graphics Controllers; USB Port Power Controllers; USB MCUs and dsPIC DSCs; Back; Browse Serial EEPROM; MAC Address and Unique ID EEPROMs Broadly, with the above-mentioned criteria, all different IC packages can be easily distinguished. All devices of the STM8S105x4/6 access line provide the following benefits: reduced system cost . Youtube channel :Taking wierd stuff apart. The leads are arranged in two parallel rows along the package length hanging vertically downwards. Some QFP packages have an exposed pad. Unlike DIP having two sides, QFP IC has pins on all four sides. For the digital logic technology, see, Last edited on 17 February 2023, at 23:37, Learn how and when to remove this template message, " 4244.256-3 ( CQFP)", HVQFN Documentation at NXP Semiconductors. Well, this happens because QFN packages have no lead in them. Quad Flat Package and Quad Flat No-leads Packages: Taking Care of Your Complex ICs The most common IC package types for larger critical components such as microcontrollers are the QFP (Quad Flat Package) and QFN (Quad Flat No-leads) packages. Latest Tech trends. These amazingly intricate packages have small balls of solder arranged in a 2D grid on the bottom. The available QFN variants are suitable for a broad range of applications. Asking for help, clarification, or responding to other answers. Next, you have to de-solder (keep the temperature profile of your component and the board in mind). Both it and the TQFP are surface-mounted packages. Other special variants include low-profile QFP (LQFP) and thin QFP (TQFP).[2]. Problematically, some manufacturers are developing metric 0201 components with dimensions of 0.25mm 0.125mm (0.0098in 0.0049in),[32] but the imperial 01005 name is already being used for the 0.4mm 0.2mm (0.0157in 0.0079in) package. The leads are vertically arranged along the boundary line of the package, just like SIP but are arranged by mutual folding in zigzag. Also, because QFN packages do not have lead, you might face some challenges when you try to desolder these packages. What is the difference between VQFP, HVQFP, TQFP & PQFP? What is the difference between LQFP and TQFP? Learn more about Stack Overflow the company, and our products. My datasheet says TQFP but has no recommended land pattern. The ICs, together with other discrete components, are assembled and interconnected on a printed circuit board or a prototyping board to produce an actually functioning electronic circuit. If you can't find a land pattern from the IC manufacturer then check very carefully the pin pitch and package size when trying to find a compatible footprint. The European Unions Registration Evaluation, Authorization and restriction of Chemicals (EU REACH) that lists the Substances of Very High Concern (SVHC) as well as substances under restriction, REACH Annex XVII. Mounting style is one of the obvious distinguishing factors in ICs. HVQFP - Heatsink Very thin Quad Flat Pack. One side might have more pins compared to another. The cut and formed mash-up of these semiconductor wafers is called a die. Array carrier features quite large cost due to fine line circuits and chemical processing technology. The QFP means (quad flat pack). Even though QFNs are pretty efficient, PCB designers tend to have an issue with them. The pin width and spacing are a bit smaller on the larger LQFP packages. These packages connect directly onto an IC (integrated circuit), semiconductor, or PCB tracks. PG-LQFP-144-22_Tape and Reel_03 Share. Metric Quad Flat Package. Self-alignment that occurs because of the surface tension of the liquid solder support reliable solder joint formation. All Rights Reserved, Multilayer PCB- Up To 56 Layers Manufacturing, Rogers PCB Full range of material manufacturer, Rigid Flex PCB Manufacturer 20L Rigid With 8L Flexible, HDI PCB Manufacturer high density interconnect Manufacturing, Low Cost RF PCB Circuit Board Manufacturing, Looking For a Good Aluminum PCB Manufacturer, Heavy Copper PCB Manufacturing Up to 20 OZ, Tursted Prototype PCB Assembly Manufacturer, Full/Partial Turnkey PCB Assembly Manufacturer, High Quality Laser Cut PCB Stencil for SMT Use, Sourcing Electronic Components Fast Quote, Estimate Bom List (Bill of Material) Cost, Different Types of BGA (Ball Grid Array) Packages, An analysis of two extensively used packaging technologies QFP and BGA, Analysis on Plating Copper Process for PCB, A Critical Analysis of 7 Layer PCB and Its Applications, Benefits and Applications of IoT smart home, Best Electrical Equipment Manufacturers in the World. A variety of techniques for interconnecting several chips within a single package have been proposed and researched: Surface-mount components are usually smaller than their counterparts with leads, and are designed to be handled by machines rather than by humans. Expand Post. These features make them suitable for higher frequency applications. LQFP VIEW RELATED DOWNLOADS The same benefits as TQFP, in a smaller package Amkor offers a broad line of LQFP (Low-profile Quad Flat Package) IC packages designed to provide the same great benefits as TQFP packaging with a 1.4 mm body thickness. Very-small Quad Flat Package MQFP. (The lead pitch and body size are smaller.) Data flags under the IEC 62474 DB field can be: Affected: Compliant to IEC 62474 DB with the use of REACH SVHC substance(s) when contained above threshold, REACH SVHCs are not restricted from use but if contained above threshold, further information must be available. A chip carrier is a rectangular package with contacts on all four edges. QFJ. QFP technology smoothens IC operations. The only difference between TQFP and QFP is the thickness, see related questions here and here. Standard QFP packages have mold compound which encompasses the entire bottom side of the package, while the EP . The short wire bonds are indication to down bonds e.g. This package type is similar to DIP except that the leads on two rows are alternatively vertical and zigzag. The discrete form is reserved for standalone components only, like a transistor, diode, resistor, capacitor, or inductor. Ultimately, the distinctions between these two packages are so subtle that it barely makes a difference which one you choose. Just as the name dictates, air cavity QFNs features an air cavity in their package. These can be used with breadboards and prototyping boards as well. Soldering your QFP in an atmosphere full of nitrogen can improve the solder joints quality. QFP (Quad Flat Package) is a gull-wing (L-shaped) package with leads coming out of four sides of the package. They have been around for decades and are still widely used. The number of pins utilized in this technology is more than one hundred, making it pretty efficient. Diisobultyl phthalate (DIBP): 0.1% (1000ppm). Um Quad Flat Package ( QFP ou encapsulamento quadrado) um encapsulamento de circuito integrado com terminais que se estendem de cada um dos quatro lados. pjr (Customer) Edited by ST Community July 21, 2018 at 5:40 PM. The die has all its components and interconnections fabricated at a microscopic level. What are the battery-selection criteria for low-power design? Logged. TQFP lead counts, on the other hand, range from 32 to 176. TQFPs are more available in smaller packages, while LQFPs are easier to attach to your PCB. The leads are possible in different shapes like linear, mutual folding, L-shape, J-shape, electrode bud, needle shape, solder bud, tape/film shape. Exceptions occur for imperial in the two smallest rectangular passive sizes. The measurement should hence be pretty accurate. Lead counts range from 32 to 256. They are ideal for the applications in lightweight and portable electronic products. The metric codes still represent the dimensions in mm, even though the imperial size codes are no longer aligned. How can we achieve this challenging feat? Later on we shall then compare and contrast them to see if there lie significant differences between the two. This is one of the most popular package styles. Well, this happens because these packages do not have flexible and long copper leads. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. The second way the IC packages can be further classified is how the pins are laid out of the device. When working with a PCB design or editing software, you may notice that both the LQFP and TQFP have the same footprint. Common package groups Defintion Package family Definition Product preference code Definition Terms Definition The common ceramic flatpack packages are CFP (Ceramic Flat Pack) and QCFP (Quad Ceramic Flat Pack). For WEEE, ppm calculations are at the component level. The common surface-mount leadless packages are LCC (Leadless Chip Carrier), PLCC (Plastic Leaded Chip Carrier), and PQFP (Plastic Quad Flat Pack). LQFP can have higher lead counts, and its leads are longer. Copyright 2023 WTWH Media LLC. The third way the IC packages can be further classified is their terminal (pin) shape. Nevertheless, they both have a maximum thickness of 1.4 mm. I'm not sure what the difference is between two, other than L stands for Low. As stated above, QFPs come in many different variations, which include: These QFPs have extensions on each of their four corners. They have impressive electrical performance, Their semiconductor package is not expensive. Expand Post. But do the two function in a similar manner? Usually, special automated tools are used to solder these on PCBs. In the past, the only difference between the two was that the former used plastic and the latter used ceramics. TQFP package having total height less than 1.2mm, said package named Thin profile Quad Flat Package. Pins are numbered counter-clockwise from the index dot. So far, we have more than 4,000 customers worldwide. The common flat pack IC packages are QFP (Quad Flat Package), TQFP (Thin Quad Flat Package), STQFP (Small Thin Quad Plastic Flat Package), FQFP (Fine-pitch Quad Flat Package), HQFP (Quad Flat Package with Heat sink), LQFP (Low profile Quad Flat Package), VQFP (Very-small Quad Flat Package), MQFP (Metric Quad Flat Package), BQFP (Bumper quad flat-pack), ETQFP (Exposed thin quad flat-package), PQFN (Power quad flat-pack), PQFP (Plastic quad flat-package), QFJ (Quad Flat J-leaded package), QFN (Quad Flat Non-leaded package), TQFN (Thin-Quad Flat No-Lead Plastic package), DFN (Dual Flat package), QFI (Quad Flat I-leaded package), HVQFN (Heat-sink very-thin quad flat-pack, no-leads), VQFN (Very-thin quad flat, no-lead), WQFN (Very-very-thin quad flat, no-lead), UQFN (Ultra-thin quad flat-pack, no-lead), and ODFN (Optical dual flat, no-lead). Day Job: Mostly LEDs. The pad is typically 10 or more mm, and with the pad soldered down onto the ground plane, heat is passed into the PCB. L3#,Exhibition Bay South,Shenzhen World Exhibition & Convention Center,Fuhai Baoan Shenzhen China, 2021 RAYMING Technology. However, they are worth the money as they have a broader application scope; they can handle applications that range between 20 25 GHz. The most common IC package types include-. Quad-flat no-leads (QFN) Now let us advance on to the next section, where we will compare QFPs and QFNs to identify the difference between the two: Here are some differences that will help you differentiate between these two devices. A low-profile quad flat package (LQFP) is a surface mount integrated circuit package format with component leads extending from each of the four sides. Lead pitches available for TQFPs are 0.4mm, 0.5mm, 0.65mm, 0.8mm, and 1.0mm. Package. The main ceramic package manufacturers are Kyocera (Japan), NTK (Japan), Test-Expert (Russia), etc. The pins just touch the PCB making the soldering process pretty easy. We use our own and third-party cookies to personalize content and analyze web traffic. Integrated Circuits rule the world of electronics. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media Privacy Policy, Have a technical question about an article or other engineering questions? Can I tell police to wait and call a lawyer when served with a search warrant? A split light system To observe the bottom portion of the QFN package plus the site on the print circuit board. TI offers 256-pin CQFP packages where decoupling capacitors can be soldered on top of the package[5] E.g. However, this close lead spacing made solder bridges more likely and put higher demands on the soldering process and alignment of parts during assembly. Amkor's TQFPs are an ideal . There are two-terminal, three-terminal, four-terminal, five-terminal, six-terminal, and more than six-terminal IC packages. Low profi le Quad Flat Package VQFP. These packages are useful in reducing the PCB cost by eliminating the need to reduce the wiring pitch. Why does this occur? HTQFP48 SOT545-2 Not suitable for wave soldering. SMD IC packages usually need custom PCBs, containing a matching pattern of copper on which they are to be soldered. Note that as the pin pitch becomes narrower, the lead pins bend more easily. Connect and share knowledge within a single location that is structured and easy to search. The J-leaded packages were developed to reduce the space required on the substrate. The IC packaging is all about encasing the semiconductor die and taking out macroscopic electrical contacts for interconnections on a PCB. Quad flat No-lead packages and Quad flat packages are both pretty impressive devices. Packing. Well, in this article, we shall look at QFN and QFP in detail. The core of any IC are semiconductor wafers that are layered in a complex formation with copper and other materials. TO determine the soldering paste volume to use, you should check on the stencil thickness and the stencil aperture. Some package types have standardized dimensions and tolerances, and are registered with trade industry associations such as JEDEC and Pro Electron. Lead pitch values used by CQFP's range from 0.5 mm to 1.27 mm. Why are physically impossible and logically impossible concepts considered separate in terms of probability? Do you work with programmable modules, PCBs, or microcomputers? Standard DIP with 0.1in (2.54mm) pin spacing, rows 0.3in (7.62mm) apart. See, when it comes to reducing fault rates in reflowing and placement, they tend to encounter some challenges. The single row configuration QFN packages are formed using the following processes: Both of these procedures split up an extensive package collection into solitary packages. If this two are not accurate then the results will be catastrophic. quad-flat no-leads TO-XX: wide range of small pin count packages often used for discrete parts like transistors or diodes. Low Profile Quad Flat Pack (LQFP) is a surface-mount IC package with leads extending from all around four sides of the package body. The latest AURIX TC3xx microcontrollers are also well-suited for safety-critical applications to support clean, autonomous and connected cars. Thanks for contributing an answer to Electrical Engineering Stack Exchange! QFPs have small parasitic parameters, and they are also pretty tiny in size. No: Not compliant to EU REACH a restricted substance(s) under REACH Annex XVII is contained outside of allowed application. When the print circuit board joins reflow oven, a number of parts start to heat up quicker than others. What am I doing wrong here in the PlotLegends specification? The packaging decides a lot of things. Search. 06_00 | Nov 12, 2020 | PDF | 1.44 mb . [1] The later pin grid array (PGA) and ball grid array (BGA) packages, by allowing connections to be made over the area of the package and not just around the edges, allowed for higher pin counts with similar package sizes, and reduced the problems with close lead spacing. QFP typically have 32 to 208 pins placed in a pitch of 0.4 to 1 mm. Issues to take note of when dealing with QFPs qfp Packages Quad Flat Package damage QFP pins are pretty small, plus they have small spacings. There are many IC packages, and most of the ICs come in more than one package. Network Consists of Further Focused Websites (Channels), All About Points, Achievement Unlocks & Gaining Ranks, Top 10 Users on ElectronicsForU's Leaderboard, Amazing DIY projects. Variation of WLCSP. Through-hole packages are bigger and easy to work with. Ball grid array (BGA) uses the underside of the package to place pads with balls of solder in grid pattern as connections to PCB.[1][3]. Through-hole technology uses holes drilled through the printed circuit board (PCB) for mounting the components. It is mounted directly to the PCB using bonding wires and covered with a blob of black Epoxy. You have to carry put this process before moving on to the placement process. Square QFP packages are pretty attractive to a lot of users. The TQFP(thin quad flat pack ) is a low-profile version of the regular quad flat package. QFN (quad flat no-lead) package is a semiconductor set connecting ASCIC to Printed circuit board (PCB). The nature of simulating nature: A Q&A with IBM Quantum researcher Dr. Jamie We've added a "Necessary cookies only" option to the cookie consent popup. In production, is there a significant difference between QFN or TQFP components other than space? A place where magic is studied and practiced? Another dimensional change suffered by this package is board flexure. They are used for mainstream cost sensitive applications. Pins on a QFP IC are usually spaced anywhere from 0.4mm to 1mm apart. Now i understand difference DIP vs SMD Packages. They have a height of 1mm and a standard lead-frame footprint of 2.0mm. Generally, these packages are extensively utilized by very large-scale and large-scale ICs. The drawing below show the package structure difference between a punched and sawn QFN. This is an even smaller version of the SOIC package. TIs latest REACH statement is located on our Environmental information page. Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. Body sizes range from 5mm x 5mm to 20 x 20mm. On the other hand little soldering paste reduces solder spreading. Then you should automatically know that it is plastic. Applications for this robust package can include commercial, automotive, and industrial products. Wettable Flanks QFNs have an elevation reflecting solder wetting. HTQFP32 SOT547-2 Not suitable for wave soldering. and offer the full pincount range. Print. The typical LQFP body thickness is 1.4 mm. These packages have a single row of pins and have a through-hole mounting style. The leadless types have electrode pads as the terminals for the connections. Normally, electronic components are available in multiple IC packages to suit different phases of product development (like prototyping and production) and suit different circuit design considerations. Lead (Pb): 0.1% (1000ppm), 2. LQFP 1.4 XXXXXXXXXX LQFP-EP 1.4 X X X X TQFP-EP 1.0 X X QFP >1.6 X XX XX PQFP 3.6 X . Furthermore, the board stiffness itself has a significant influence on the reliability of the solder joint interconnect if the system is used in critical temperature-cycling conditions. Like how the connections are organized in an IC, how they are laid out using a standard IC package must be coherent with the application and various use cases of the respective IC. 144-pin low profile quad flat package (LQFP), 80-pin thin quad flat package (TQFP) PIC microcontroller, 304-pin plastic quad flat package (QFP) with exposed thermal pad (TP), 100-pin bumpered quad flat package (BQFP) Cyrix Cx486SLC, 80-pin ceramic quad flat package (TQFP) ST6 microcontroller. This technology realizes that the distance between the pins of the CPU chip is very small, and the pins are very thin. Surface Mount Device Package", "National Semiconductor CERPACK Package Products", "National Semiconductor CQGP Package Products", "National Semiconductor Launches New Generation of Ultra-Miniature, High Pin-Count Integrated Circuit Packages", "Conexant Systems, Inc. - Conexant First to Launch DVB-S2 Demodulator and FEC Decoder", "Press Releases - Motorola Mobility, Inc", "Understanding Flip-Chip and Chip-Scale Package Technologies and Their Applications - Maxim", https://www.nxp.com/docs/en/application-note/AN3846.pdf, "Packaging Technology | National Semiconductor Package Drawings, Part Marking, Package Codes, LLP, micro SMD, Micro-Array", "How Chip-On-Boards are Made - SparkFun Learn", "TSSOP-8 Package Dimensions by Diodes Incorporated", "F Package -- 14-Lead Plastic TSSOP (4.4mm)-- (Reference LTC DWG # 05-08-1650)", "F Package -- 20-Lead Plastic TSSOP (4.4mm) -- (Reference LTC DWG # 05-08-1650)", http://pdfserv.maximintegrated.com/package_dwgs/21-0036.PDF, "Murata's world's Smallest Monolithic Ceramic Capacitor - 0201 size (0.25 mm x 0.125 mm)", "White Paper 0201 and 01005 Adoption in Industry", "SMR Series Ultra-Compact Chip Resistors", "SMD/BLOCK Type EMI Suppression Filters EMIFIL", "TLJ Series - Tantalum Solid Electrolytic Chip Capacitors High CV Consumer Series", "Tantalum Surface Mount Capacitors - Standard Tantalum", "Application Guide - Aluminum SMT Capacitors", "Surface Mount Aluminum Electrolytic Capacitors - Alchip-MVA Series", "SOD 80C Hermetically sealed glass surface-mounted package", "Designer's Data Sheet - Surface Mount Silicon Zener Diodes - Plastic SOD-123 Package", "SOD128 plastic, surface mounted package", "SOD323 plastic, surface-mounted package", "SOD923 Microlead ultra small surface-mounted plastic package", "Package Outline Dimensions - U-DFN1616-6 (Type F)", "3-Lead Small Outline Transistor Package [SOT-89] (RK-3)", "Standards for the Dimensions of Semiconductor Devices", Electronic Industries Association of Japan, https://www.analog.com/media/en/package-pcb-resources/package/pkg_pdf/sot-143ra/ra_4.pdf, "D3PAK: Decawatt Package 3 (TO-268, Discrete Package) | MADPCB", "SOT891 XSON6: plastic extremely thin small outline package; noleads", An illustrated listing of different package types, with links to typical dimensions/features of each, International Microelectronics And Packaging Society, https://en.wikipedia.org/w/index.php?title=List_of_integrated_circuit_packaging_types&oldid=1139870627, All articles with bare URLs for citations, Articles with bare URLs for citations from March 2022, Articles with PDF format bare URLs for citations, Short description is different from Wikidata, Articles with bare URLs for citations from June 2022, Articles covered by WikiProject Wikify from June 2022, All articles covered by WikiProject Wikify, Wikipedia articles needing clarification from July 2018, Creative Commons Attribution-ShareAlike License 3.0.