![]() Preferred: 10 mil Limit: 8 mil Soldermask expansion is space around pads that are not covered by soldermask Don’t put SMT pads so close that there is no soldermask between them (very hard to solder)ġ6 Design Rules: Hole/Via Size and Annular RingĮnsure that pins/wires fit in holes Warning: the plating will make holes smaller Size and annular ring must be greater than manufacturer’s min. Must be large enough to handle current Signal Nodes: Preferred: 10 mil Limit: 8 mil Power Nodes: Preferred: 30 mil Limit: 20 milġ5 Design Rules: Clearance and Soldermask Expansion house: Trace width Clearance Via size Annular ring Hole size restrictions Soldermask expansion (swell) Run DRC (design rule check) after each change DRC violations highlighted in green By hand (if very few components) or automatically using Altium’s tools Compile the design (will generate netlist) Read and address all errors and warnings Re-compile after making all changesġ2 Steps Draw schematics Attach footprints for all componentsġ3 Design Rules Defined by PCB manufacturer ![]() annular ring Soldermask expansionġ0 Steps Draw schematics Attach footprints for all componentsġ1 Compile Design Annotate design by adding designators #Good examples for pcb altium designer how to#Most library footprints are not for soldering by hand (so, edit them or draw your own) Refer to mechanical drawings in datasheets Select correct units (mil or mm) Make pads longer than pins (at least 1 mm) Make holes larger than pins Use soldermask to show how to align part Check design rules: Min spacing Min. ![]() Make sure pin numbers on footprint match component Carefully check all footprint from libraries All components must have a footprint Print out footprints (on paper) and test the fit Wires must touch to make a connection Use NetLabels to label all wires Can make your life easier in PCB layout For large complicated designs, connect by net rather than by connection Use buses Must label all signals pulled from buses Ensure that VCC and GND are labeled correctly (everywhere) No shorts (like VCC and GND, for example)ħ Steps Draw schematics Attach footprints for all componentsĨ Footprints Choose all parts before finalizing schematicĬhoose (hand-solderable) packaging: Through-hole: DIP, PLCC, etc. ![]() ![]() CohnĬSE 477 – Hardware Capstone University of WashingtonĢ Steps Draw schematics Attach footprints for all componentsĬompile design Assign design rules Place components Check design rules Route PCB Generate manufacturing filesģ Terminology Net – representation of a signal (wire) and all of its connections SMT – surface mount component Trace (track) – metal connections on PCB between components Pad – metal on PCB where component is soldered Via – plated through-hole in PCB to connect traces on 2 sides Mil – 1/1000 of an inch (don’t confuse with mm) Pitch – spacing between pins DRC – design rule check Rat’s Nest – point-to-point drawings of all un-routed connectionsĤ Steps Draw schematics Attach footprints for all componentsĥ Schematics Components Power Testing Find in Altium librariesĭraw your own Double-check the pins Connect “hidden” pins to the correct net Power Use bypass caps for all ICs Use large filter cap on power supply Testing Test points on power lines Test points on important signals Use Power LED (for basic signs of life)Ħ Schematic Hints Use multi-sheet schematics for large designs 1 PCB Design Using Altium Designer/DXP/Protel Gabe A. ![]()
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