Our Proprietary 4-Step Layout Process Guide

At Advanced Design Services (ADS), we have seen and done it all. We thrive on challenges that advance electronic technology. Our goal is to achieve all of our customer’s requirements and do it within your schedule. To be more cost effective, we have documented the procedures to make everyone aware of all the details in each step in the Layout Process.

The Layout Process is divided in Four Main Steps. Within each step are the Engineer's input, steps taken by ADS, and approvals needed for each process before proceeding to the next step.

Estimates (Required)

The following is a List of items we need for Estimates:

  • Schematics
  • BOM (Parts List)
  • Mechanical Board Outline details
  • Statement of Work (description of critical placement and routing)
  • Testability requirements ICT

Step 1:  Customer Supplied Data (Packaging)

Input Needed (engineer)

  • Schematic   
  • Netlist       
  • Datasheets for all parts
  • Parts List with MFG Part Numbers and description of parts

Steps Taken By Ads

  • PCB Footprint Creation
  • PCB Footprint Mapping from your names to ours
  • Possible Net names Adjustment (Illegal Characters, Single Pin nets)
  • Upload Netlist into Database, report any discrepancies to customer.

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STEP 2:  Placement

Input Needed (engineer)

Mechanical Input

  • Mechanical Board outline size
  • Keepouts
  • Height Restrictions for Top and Bottom side of Board
  • Board thickness
  • Material
  • Fixed component locations
  • Connector orientation and pin # 1 locations
  • Plated vs. non-plated mechanical holes and their Clearances / Tolerances
  • Tooling holes, Standoff holes, Mounting holes
  • Card guides, Ejectors, LED's, Daughter Cards, etc…

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Placement And Route Input

  • Suggested Preliminary Placement
  • Suggested Stack-up or Layer count
  • Components allowed on Bottom /Far side of board ?
  • List of Critical Nets
    • Needs to be documented
  • Controlled Impedance/Differential Impedance Requirements
  • Matched Length traces
  • PWR nets planes, GND planes requirements
  • Thermal Issues
  • Shields (RF shields...)
  • Heat Sink requirements
  • Daisy chain nets requirements
  • Nets Schedule requirements
  • Built in Shorts requirements
  • Testability requirements ICT (large impact on cost and schedule

Steps Taken By ADS

  • Creation of Board Outline with Keep-in/Keep-outs
  • Placement of fixed component locations
  • Initial Component placement
  • Setup Default Constraints (min line width, via size, etc..)
  • Create balanced Board Stack-up, Talk to Fabrication Vendor
  • Initial setup of PWR and GND planes
  • Initial Fab Drawing
    • Add standard and detail notes
    • Add stack-up with cross section details
  • Global and Local Fiducials (Registration target for SMD components)
  • Game Plan :
    • Critical Nets and Impedance needed
    • Shields
    • Thermal items
    • ICT (tespoints if needed)

Preliminary Component Placement Review And Approval (engineer)

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Steps Taken By ADS


  • Setup constraints and
    parameters for critical nets
  • Setup of controlled
    Impedance traces
    • Calculate line width
      and spaces
  • Pre-route PWR/GND nets (Fanout/Pin Escapes)
  • Pre-route critical nets
  • Address thermal issues
  • Address Shielding issues
  • Address Testability issues

Approval For Pre-routes Needed  (engineer)

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Steps Taken By Ads

  • Test Router for completion rate if AUTOROUTER is required
  • If board needs to be hand routed allow extra time
  • Complete Routing

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Step 4:  Post Route And Cleanup

Steps Taken By ADS

  • Clean fanouts, trace entry to SMD pads
  • Smooth/Gloss nets
  • Review and Clean each Routing layers
    • Check for odd angles
    • Check for more clearances between traces and Keepouts/Mounting holes
  • General Route cleanup
  • Test Point assignments / Mask clearances
  • Silkscreen Marking (P/N, REV)
  • Silkscreen Ref Des Cleanup
  • Additional Silkscreen needed
    (polarities, pin#1 ID's)
  • Double check and adjust Documentation
    • Add dimensions to outline and locate 0,0
    • Details for Stack-up
    • Setup Fab Notes and add any special requirements
    • Board material and finish requirements
    • Board thickness
    • Impedance notes
    • Special hole tolerances (press fit holes)
    • Details for bevels, slots, cutouts, countersink holes, scoring, break away tabs, etc…
  • Review Solder Mask requirements
  • Review Solder Paste ( stencil) requirements
  • Review ***SUMMARY REPORT***
           100% connected, DRC Free, unplaced components, 0 dangling lines


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Customer Approval Needed (engineer)

Steps Taken By Ads (provide Final Data To Customer)

  • Customer cleanup comments addressed
  • Renaming of Reference Designators if required
  • Provide Was-Is list to back annotate schematic if required
  • Final Netlist provided by customer for final check comparison
  • Final Design Approval
  • Delivery of final Package (6 different ZIP files provided )

This is ADVANCED DESIGN SERVICES’ standard output for each design.

Each design will have 6 zip files
Please note "XXXXXX" is for the name or part number of the board with revision

1-      Everything the MFG needs to assemble the board.
       data.file            UNICAM FILE FOR ASSEMBLY
       route.txt            VALOUT FILES FOR ASSEMBLY                               
       board.txt            “                                       
       pad.txt               “
       symbol.txt           “
       testprep.log         TEST POINT REPORT
       XXX-ccam.cad             CIRCUIT CAM FILE

2-      Everything the Vendor needs to fabricate the bare board (Gerber Files).        fabrication drawing        layer 01 thru however many layers there are.        solder mask top        solder mask bottom        solder paste top        solder paste bottom        silk screen top        silk screen bottom
       photoplot.log        Photoplot/Gerber log file
       art_aper.txt         Aperture list
       art_param.txt        Gerber parameters

       ADS-001.tap        NC Drill file
       nctape.log           NC Drill count  
testprep.log         TEST POINT REPORT
       XXXXXX.ipc           IPC 356 NET LIST for E-Test
3-      CAD Database and reports for Archive
       net.rpt                ALLEGRO NET LIST FILE.
       place.rpt              COMPONENT (X, Y POSITION)
       sum.rpt                ALLEGRO SUMMARY REPORT
       testprep.log           TEST POINT REPORT
4-      DXF files for every layer.
       asyt.dxf               ASSEMBLY TOP DXF FILE
       asyb.dxf               ASSEMBLY BOTTOM DXF FILE
       fab.dxf                FABRICATION DRAWING DXF FILE

5-      PDF files for every layer.
       asyt.pdf               ASSEMBLY TOP PDF FILE
       asyb.pdf               ASSEMBLY BOTTOM PDF FILE
       fab.pdf                FABRICATION DRAWING PDF FILE

6-        ODB++ Manufacturing files

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