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    PCB Design Analysis Software Guidelines

    HyperLynx Applications

    1.0 Introduction

    HyperSuite EXT software is primarily for the analysis of electronic Printed Circuit Board (PCB) design as an aid in minimizing potential PCB design problems that can contribute to electromagnetic emissions. Use of the software analysis services throughout the PCB design cycle can help eliminate any circuit design revisions needed to address signal integrity, crosstalk, and emission problems. The optimization of PCB performance provides an effective means of preparing equipment for meeting applicable EMC test requirements. Proper planning for use of the software can result in lower overall development costs for most electronic equipment. HyperSuite EXT is a highspeed PCB design suite that includes signalintegrity, crosstalk, and EMC analysis tools. It provides for the analysis of highspeed designs early in the design cycle and prior to layout (LineSim); after placement but prior to routing, or after placement and routing of a few critical nets (BoardSim); and after complete PCB layout (BoardSim). Single boards and multiboard systems may be analyzed using LineSim or BoardSim. LineSim is also useful for generating the constraints needed for high speed PCB routing. Interactive simulations may be run for a quick analysis of any critical nets or the batch mode may be used for simulation of a large number of nets simultaneously.

    2.0 Procedures

    Application of the software design and analysis tools becomes more beneficial if the PCB design process is properly planned and tailored for their use. Plans should be made to make efficient use of the software applications throughout the PCB design process. The following is a description of the HyperLynx software suite analysis capabilities and the recommended sequence of application.

    2.1 PreLayout Fast Analysis

    A fast analysis should be used at the schematic level to identify and determine suitable “whatif” design alternatives. Layout files are not needed for this application. LineSim is an excellent tool for solving signal integrity and EMC problems early in the design cycle, prior to investing time in the PCB layout. Critical nets and signals with fast switching characteristics should be identified as high priority candidates for the prelayout analysis. These are usually associated with clock signals and the devices having rapid transition times. Any applicable constraints should be determined for the critical nets and signals. Constraints may be used during the analysis for increased accuracy and as an aid when the critical nets are routed. Exact device models are not needed early in the design process since this type of information may not be available. Models may be determined and added as the design materializes.

PCB layout PCB assembly

  • pcb layout design, PCB assembly, Electronic manufacturing
    PostLayout Detailed Analysis

    A detailed postlayout analysis should be done using the layout tool files saved in the “hyp” extension. There are some problems that can only be determined after PCB layout. For example, a properly designed net can be affected by the board’s overall layout characteristics and geometry. If a trace length is not constrained properly during routing, or if a net overly extends itself between board layers, there can be some unanticipated problems. BoardSim is usually used after layout and routing since the analysis is based on actual details of a board's routing. However, it can also analyze a board as soon as it is placed, prior to routing, by using Manhattan Routing that BoardSim creates; or when the board is placed and only partially routed.

    2.2.1 Input Files

    The initial step in running BoardSim is to translate the PCB layout into BoardSim's file format (".HYP"). OrCAD is a good layout software tool for this purpose. However, board layout files are acceptable from several different layout tools and boards from different layout programs may be mixed. Some PCB layout tools contain a BoardSim translator that is available as a menu item. Other tools may require an external translator that is supplied with BoardSim. BoardSim supports the following PCB layout tools: OrCAD Layout, Protel Advanced PCB, Accel EDA / PCAD, Cadence Allegro, Innoveda PowerPCB (formerly PADS), Mentor BoardStation and Veribest, ZukenRedac Visula / Cadstar, Zuken CR3000 / 5000.

    BoardSim's MultiBoard option provides the capability to load multiple boards simultaneously, interconnect them, and simulate the PCB’s as a system. The files for each board may be in .HYP file format, or in a type of I/O Buffer Information Specification (IBIS) board model called Electrical Board Description (.EBD). The EBD format allows for modeling of random interconnects, and it can be used to represent PCBs, complex IC packages, and custom modules. If the equipment to be analyzed consists of locally designed PCBs, it is recommended that all of the boards be made avaliable as .HYP files. Third party boards such as memory modules may be provided in EBD format. The primary difference between the .HYP file and an EBD model is that the .HYP file contains physical details about trace routing, stackup, etc. EBD models are completely electrical with the interconnects represented as transmission lines and precalculated inductance, capacitance, impedance and delays. An .HYP file can be viewed since it is based on a physical routing; however, an EBD file has no physical information to display. Either file type may be used to include the effects of plugin modules and boards for a multiboard simulation.

    2.2.2 Models

    Detailed device models may be created during the design analysis process. The I/O Buffer Information Specification (IBIS) standard is used by most IC manufacturers to provide models for their devices. IBIS models are widely available and can usually be downloaded from vendor web sites. HyperLynx supplies more than 6,900 IC models with BoardSim and LineSim. HyperLynx provides a special spreadsheet and component database for searching and sorting models based on manufacturer, part name, creation date, function, etc. Models may also be created for specialty or custom IC’s that are not included in vendor or HyperLynx libraries.

    Utilities are available to create the IBIS models from SPICE net lists. SPICE is useful for designing mixedsignal systems since HyperLynx does not have analog models. In some cases, a vendor may supply SPICE models because the IBIS models are not yet available. SPICE Writer is available as an option in LineSim and in BoardSim to automatically generate a SPICE netlist output file containing a complete description of a schematic (LineSim) or selected net (BoardSim) using SPICE transmission line elements. This output file also contains the passive components for the selected net as well as comment lines listing the drivers and receivers for which the user can provide SPICE models.

    A detailed analysis may be performed on the critical nets and signals once the models that contain all of the required information are established. If the analysis indicates any potential emission problems, corrective action should be taken to modify the layout. After the placement of all critical devices has been determined, the routing patterns for critical signals can be specified. Trace routing constraints may be captured as a topology rule for reducing emission levels.

    The radiation produced by a net's component packages can be as significant as that generated by the net's trace segments. BoardSim has the capability to analyze a device package's footprint to determine the package style (DIP, SOIC, etc.) and automatically generate a radiation model for the package.

    3.0 Documentation

    When all of the design constraints have been achieved and a detailed analysis of the critical nets does not indicate any potential problems, the design may proceed to the fabrication phase. The report and documentation capability of HyperSuite consists of schematic printing (LineSim), for documentation of interconnect circuits; board and net statistic summaries; and an archiving feature that can combine all of the design files (.HYP, IC models, session edits, etc.) into a single directory or zip file.

    4.0 Recommendations

    Any proposed PCB design changes should be carefully considered for possible impacts to other design objectives, such as overall circuit functionality, size requirements, manufacturing constraints, and thermal effects. Design changes made to reduce electromagnetic emissions may impact other circuit requirements. Some design alternatives may result in a higher level of PCB design complexity in order to optimize EMC performance. This may increase the cost of the circuitry and system of boards. A typical case is a design that requires an increase in the number of board layers to reduce electromagnetic emissions to acceptable levels, thus increasing board manufacturing costs. Some situations may require a more detailed analysis which takes into account the enclosure shielding, board image planes and EMI filters in order to compromise on such design changes FREE PCB design software, PCB Design service and FabricationWe offer PCB Design, Fabrication and assembly Service at a very very competitive ... PCB Design Layout ? Multiple Width Route Codes ? EMC & Thermal Analysis PCB Design Layout Services, Autorouting, Schematic Captureprinted circuit board layout pcb design services prototype developement. ... leading software products and follow IPC 275 guidelines in our designs. Layout ...
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    PSpice and SPECCTRA.DESIGN
    Mindlink Technologies offers a range of services in Printed Circuit Board (PCB) design on a contract/quote or time & materials basis. Whether a specific design task or a full range service is required we can meet your requirements. Design facilities include PCB layout, schematic entry and mechanical CAD as well as electronic circuit design.

    Our emphasis is on quality workmanship, properly detailed, in a timely manner. Large or small, simple or complex, we can provide a design solution for your requirements.


    PCB Layout
    Based on created or customersupplied schematics or netlists, PCB designs can be produced to required specs. Design rules such as trace width, annular ring, component placement, footprints ect. are adhered to based on IPC guidelines or customer specification. Analog, power and critical signals are manually routed while most digital signals are autorouted to reduce design time and costs. Single to multilayer design capabilities. Boardshopready artwork is provided in Gerber format and can be accompanied by IPC356 netlist data.

    Analog, digital
    Multilayer (4 16+) design
    BGA, controlled impedance, matched length routing
    HV and power supply, UL, CSA spec
    Design to IPC2221/2 Standards
    Flooded, CAM, Split/Mixed Planes
    Decal/Footprint creation
    Manual/Dynamic routing
    Autorouting (Rule and Shape based)
    Gerber output RS274D, RS274X
    PCB Specification document
    IPC356A netlist & fabrication data
    Design For Fabrication/Manufacture
    IPC Certification (CID)
    see Services page for additional design related services

    PCB Layout tools currently supported:
    PADS PowerPCB 3.6, 4.01
    Orcad Layout Plus 7.1, 9.2
    Cadstar 7 (DOS)
    PADS BlazeRouter Autorouter
    Cadence SPECCTRA Autorouter
    Cam350 Gerber Editor
    Go to Top of page


    Schematic Entry
    Entry of circuit details into schematic form is an essential requirement for the transfer of the circuit to PCB Layout. PCB footprint or decal information as well as specific design rules e.g. trace width and spacings, differential pairs, layer definition, ect. ensure PCB layout is correctly setup. For inprocess updates or Engineering Change Orders (ECO), transferring those changes to or from the PCB ensures the circuit design matches the PCB design. Various output formats are available for design review or final documentation archiving.

    Entry from various forms (handdrawn, CAD, even ‘napkin scribbles’ !)
    Complete design to data sheet check
    Decal creation and verification
    Design rule, PCB parameter entry
    PCB Footprint setup & verification
    Company logo and sheet style creation
    Printing services (PDF, HPGL, DXF, hardcopy)
    Transfer to PCB netlist (see Services for translation abilities)
    BOM and parts list compilation
    ECO updates
    Design block diagrams
    Schematic Entry tools currently supported:
    PADS PowerLogic 3.5, 4.01
    Orcad Capture 7.2, 9.2
    Cadstar 7 (DOS)
    Go to Top of page


    Mechanical CAD
    While not a full mechanical design service, Mindlink Technologies provides mechanical CAD services for the purposes of PCB production and assembly documentation. In addition, mechanical fixtures and accessories drawings can also be created.

    We are currently evaluating SolidWorks for 3D Solids parts and assemblies. We will be concentrating on racks, chassis, 3D electronic parts and PCB assemblies. In addition, we are working on software to link PCB design applications to SolidWorks for 3D rendered visuals, interference analysis and assembly documention.

    Detailed PCB assembly drawings
    Production drawings (wiring, assembly visuals)
    3D assembly profiling (Solids)
    Enclosures
    Brackets, heatsinks
    DXF, DWG format
    IDF ECAD exchange
    3D PCB part creation services
    Mechanical CAD software currently supported:
    AutoCAD 14, 2000, 2002
    SolidWorks 2001, 2001+ PADS PowerPCB to SolidWorks
    Snapper System Modules

    Data Storage Solutions

    Electronic Design

    Design Process

    Research & Development

    Embedded Technology

    USB

    Ethernet

    RS232

    RS485

    WIFI

    GPS

    GPRS

    Bluetooth

    Zigbee

    Display

    NAND

    Compact Flash

    Storage

    SDRAM

    Battery

    Power over Ethernet

    Audio

    GPIO

    I2C

    I2S

    SPI

    Form Factor

    Prototyping

    Placement

    PCB Layout

    Bringup

    Schematic

    Bill of Materials . ERP

    Camera

    Embedded Software

    Squid

    Autotester

    Test Jigs

    Product Showcase

    Design Quote

    Terms and Condition

    Contact

    ARM Development Tools PCB Layout
    Inroduction
    PCB Layout.Routing is the next step after component placement in PCB design work. It is the actual physical pointtopoint connection of nets driven by the circuit schematic. All of this design work from schematic capture to component placement until PCB routing are done through EDA CAD software tools (Cadence Allegro in our case).

    PCB layout topic is a very broad field and involves many steps and guidelines to complete the design process. Discussions here will be limited to aspects relating to embedded design systems. PCB layout work, in general, is not just connecting traces but also includes making a specification of the PCB that meets the requirements of the project. This involves determining what PCB technology to use (doublesided or multilayers, throughhole vias or blind.buried.laser vias, trace width.spacing, layer stackup, etc). It all depends on the complexity of the circuit and its required features. After making a PCB specification, connectivity work can begin until all nets are connected. The final output of this is generating, what are called in the PCB industry as Gerber files (see http:..en.wikipedia.org.wiki.Gerber_File) and fabrication drawings, which are then being sent to a PCB fabricator to build the PCB (see http:..en.wikipedia.org.wiki.Printed_circuit_board).

    In summary, PCB layout is the final electricallyrelated design work of putting the whole project concept into its physical reality. Though this is schematicdriven from circuit design, it can also “make or break” a project if its not done properly.


    Snapper PCB layout in Cadence Allegro (all layers on) Actual Snapper

    PCB layout stages:
    Determining the electrical requirements
    Embedded systems can have the same features as a normal desktop PC have depending on its target application. Though it may be slower in speed compared to most modern PCs nowadays, it still employs the same basic circuit requirements (CPUs, SDRAMs, Memory storage, etc.) and interfacing options (LCDs, USB, Ethernet, WiFi, Bluetooth, GPS.GPRS, PoweroverEthernet, power supplies, etc.). Most of these have circuits that are critical in nature and employ highspeed electrical signalling (CPU to SDRAM interface, highspeed clock lines, differential signalling for USB.Ethernet and LVDS for certain types of LCDs, RF antenna traces, analog.audio signals, etc.) which require highspeed and mixed RF.AnalogDigital PCB layout techniques to be employed during routing and specifying PCB requirements (see more http:..en.wikipedia.org.wiki.Printed_circuit_board#Design_guidelines). This usually requires controlledimpedances (singleended.differential impedance) on traces carrying these signals and matching length these traces during layout. This will also determine the number of layers and layerstack configuration buildup of the PCB. This will form the bulk of the PCB specification along with the required mechanical dimensions, PCB material and finish, silkscreen, soldermask and drill tolerance.


    Determining the nature of electronic components used (finepitch surface mounts or throughhole)
    Because of the requirement of the final product of most embedded systems to be small in size, small finepitch surfacemount components (BGAs, QFNs, DFNs, FCSP, etc.) are generally used. Development boards don't have this same restriction as the final product, so they may end up using standard component packages (SOICs, QFPs, throughhole connectors, etc). Knowing these components is another requirement that will determine the trace width.spacing and throughhole or blind.buried vias to use in the PCB. As the board gets very dense and highly complicated, so does the cost of building the PCBs and this will increase the cost.


    Verifying the PCB specifications with a PCB manufacturer
    When working with new PCB manufacturer or when special PCB requirements are needed (such as special PCB material for RF Gigahertz speed application), it is always best to check with the intended PCB manufacturer whether the PCB can be manufactured or if tweakings are needed at their end to meet the desired specification. This step is not necessarily needed if the designer is using a specific PCB vendor for quite some time and is already familiar with their capabilities.


    PCB layout or routing
    Having the prerequisites (electrical requirements and PCB specifications) determined in the first two steps above, the actual connection of nets or layout can commence keeping in mind all the critical circuits or areas that needed special care and applying good engineering practices when dealing with highspeed digital, RF.analog or a mixed of both. It generally make sense to route these difficult areas first and byhand rather than relying on an Autorouter. In small embedded systems where you have limited space or room, doing the layout byhand is almost always the best approach. Autorouter usually comes into play when routing noncritical areas of the board and when working with large development boards where space or room is not an issue. Another important thing to consider is Design for Manufacturability (DFM see http:..en.wikipedia.org.wiki.Design_for_manufacturability_%28PCB%29 for details) to ensure that the overall PCB, from component placement to layout, is manufacturable.
    PCB layout review
    This is always done in concurrence with the circuit design engineer and sometimes, people from manufacturing and assembly for large volume production. For very critical boards, it is always best to do a review after the critical areas are done and another review when the whole layout is completed.


    Gerber generation.netlist verification, fabrication drawing
    Gerbers are standard output files from PCB CAD software .Cadence Allegro. sent to a PCB fabricator and used to build the PCBs. Before these are sent, it is always advisable to do some visual checkings on these files as these are the link between the design files and actual PCB. Another method of checking is IPC356 netlist verification. It extracts a netlist out of the gerber files, compares this netlist from an IPC356 netlist format generated by the PCB CAD tool and generates error reports if it finds any discrepancies. This is a more sure way of verifying that gerber files and PCB design files are in sync.


    DDS PCB Gerber files .as viewed using Gerber viewer. Snapper showing inner layers

    In one particular Snapper module, called Snapper270, two 56ball BGA at 0.65mm pitch were used because of their small size. This is a very finepitch BGA. To fanout the pads, it would normally require laserdrilled blind.buried microvia. But through careful component placement, pinout assignments and routing strategy, we were able to get away with it and just use conventional throughhole vias during fanout and kept the cost low .see snapshot of this below with the finepitch BGAs highlighted.

    Snapper270 BGA layout

    Rig 200 PCB Layout
    The Rig 200 PCB, with its formfactor derived from a standard 5.25 inch CDROM bay, measures 199mm by 140mm. But packed will all the features one can think of, ended up being a highlydensed populated board and so does the routing with the addition of a Snapper SODIMM version support.

    Rig 200 PCB showing all layers .in Cadence Allegro.


    Actual Rig 200


For furhter information, please feel free to contact us, www.pcbsino.com