Difference between revisions of "EAGLE Style Guide"

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m (footprint layer tValues should be 27 not 26)
 
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=Part Creation=
 
=Part Creation=
−
 
 
==Symbol==
 
==Symbol==
 
===Grid===
 
===Grid===
Line 15: Line 14:
 
**Keep text horizontal
 
**Keep text horizontal
 
**'''Size:''' 0.07 in
 
**'''Size:''' 0.07 in
−
**'''Ratio:''' 8%
 
 
**'''Line Distance:''' 50%
 
**'''Line Distance:''' 50%
 
**'''Font:''' proportional
 
**'''Font:''' proportional
Line 35: Line 33:
 
***'''Curve:''' 0
 
***'''Curve:''' 0
 
**Try to have a length/width that is a 0.1 in multiple (eg. 0.4 in by 0.4 in)
 
**Try to have a length/width that is a 0.1 in multiple (eg. 0.4 in by 0.4 in)
 +
 
===Functionality===
 
===Functionality===
 
*Pins
 
*Pins
Line 58: Line 57:
 
*Decimal Labeling
 
*Decimal Labeling
 
**For fractional values include the decimal point (eg. 3.3V, 4.5K)
 
**For fractional values include the decimal point (eg. 3.3V, 4.5K)
−
 
 
==Footprint==
 
==Footprint==
 
===Grid===
 
===Grid===
Line 73: Line 71:
 
**Keep text horizontal
 
**Keep text horizontal
 
**'''Size:''' 1 mm
 
**'''Size:''' 1 mm
−
**'''Ratio:''' 8%
+
**'''Ratio:''' 10%
 
**'''Line Distance:''' 50%
 
**'''Line Distance:''' 50%
 
**'''Font:''' vector
 
**'''Font:''' vector
Line 84: Line 82:
 
**Locate in bottom-left of symbol
 
**Locate in bottom-left of symbol
 
**'''Align:''' top-left
 
**'''Align:''' top-left
−
**'''Layer:''' 26 tValues
+
**'''Layer:''' 27 tValues
 
**'''Value:''' >VALUE
 
**'''Value:''' >VALUE
 
*Outline
 
*Outline
Line 104: Line 102:
 
***'''Style:''' continuous
 
***'''Style:''' continuous
 
***'''Layer:''' 51 tDocu
 
***'''Layer:''' 51 tDocu
 +
 
===Functionality===
 
===Functionality===
 
*Pad (Through-hole)
 
*Pad (Through-hole)
Line 137: Line 136:
 
****'''Radius:''' 0.2 mm (at minimum)
 
****'''Radius:''' 0.2 mm (at minimum)
 
**Avoid overlapping pads with silkscreen, cut a section out
 
**Avoid overlapping pads with silkscreen, cut a section out
−
 
 
==Device==
 
==Device==
−
===Attributes===
+
===Name===
−
*Name should be manufacturer part number
+
*Should be manufacturer part number (eg. ATTINY167-SU)
−
*Attribute - DKPN should be filled with the Digi-Key part number
+
*Wildcards
−
===Descriptions===
+
**Allows devices with multiple technologies (specifications) or packages
−
*One sentence describes the function of the part
+
***Uses wildcards in device name
−
*Datasheet link (if available)
+
***Technology Name: *
 +
***Package Name: ?
 +
**Example
 +
***Regulator with two voltage (3.3V and 1.8V) technologies
 +
****AP2138N-3.3TRG1 for 3.3V
 +
****AP2138N-1.8TRG1 for 1.8V
 +
****Becomes AP2138N-*TRG1 with technology 3.3 and 1.8
 +
===Description===
 +
*One sentence part function overview (valid for all variants)
 +
*Datasheet link
 +
===Value===
 +
*Off unless its a passive part (resistors, capacitors, inductors, fuses, diodes)
 +
*If its a specific passive part with a value, add an attribute
 +
**'''Name:''' VALUE
 +
**'''Value:''' the value
 +
**'''Type:''' variable
 +
===Symbol===
 +
*Use specific symbol for that part/family
 +
*Connectors are an exception
 +
**Generic symbol used for all connectors of a certain size
 +
===Footprint===
 +
*Use specific footprint if unique
 +
*Try to reuse a footprint if it matches
 +
===Attribute (non-Passives)===
 +
*Part number
 +
**'''Name:''' DKPN
 +
**'''Value:''' the Digi-Key Part Number (eg. ATTINY167-SU-ND)
 +
**'''Type:''' variable
 +
===Attribute (Passives)===
 +
*Part number
 +
**'''Name:''' DKPN
 +
**'''Value:''' blank unless specific to part
 +
**'''Type:''' variable
 +
*Resistors
 +
**Should have tolerance and power ratings that is blank by default
 +
**Value is for resistance only
 +
**Tolerance
 +
***'''Name:''' TOL
 +
***'''Value:''' blank unless specific to part
 +
***'''Type:''' variable
 +
**Power
 +
***'''Name:''' POW
 +
***'''Value:''' blank unless specific to part
 +
***'''Type:''' variable
 +
*Capacitors
 +
**Should have tolerance and voltage ratings that is blank by default
 +
**Value is for capacitance only
 +
**Tolerance
 +
***'''Name:''' TOL
 +
***'''Value:''' blank unless specific to part
 +
***'''Type:''' variable
 +
**Voltage
 +
***'''Name:''' VOLT
 +
***'''Value:''' blank unless specific to part
 +
***'''Type:''' variable
 +
*Inductors
 +
**Should have tolerance and current ratings that is blank by default
 +
**Value is for inductance only
 +
**Tolerance
 +
***'''Name:''' TOL
 +
***'''Value:''' blank unless specific to part
 +
***'''Type:''' variable
 +
**Current
 +
***'''Name:''' CUR
 +
***'''Value:''' blank unless specific to part
 +
***'''Type:''' variable
 +
*Fuses
 +
**Value is for current rating
 +
*Diodes
 +
**LEDs
 +
***Value should be color
 +
**Normal Diode
 +
***Value should be reverse voltage
 +
**TVS Diode
 +
***Value should be [Working Voltage]-[Breakdown Voltage] (e.g. 8V-8.5V)
  
 
===Prefix===
 
===Prefix===
 
{| class="wikitable"
 
{| class="wikitable"
−
|+ Chart for Designation
+
|+ Chart for Prefix Designators
 
|-
 
|-
 
! Letter
 
! Letter
Line 154: Line 226:
 
|-
 
|-
 
| A
 
| A
−
| Separable assembly or sub-assembly (e.g. printed circuit assembly)
+
| Separate Assembly or Subassembly
 
|-
 
|-
 
| C
 
| C
Line 160: Line 232:
 
|-
 
|-
 
| D
 
| D
−
| Diode, LED
+
| Diode or LED
 
|-
 
|-
 
| F
 
| F
Line 188: Line 260:
 
| P
 
| P
 
| Plug (most moveable connection part)
 
| Plug (most moveable connection part)
 +
|-
 +
| POT
 +
| Potentiometer
 
|-
 
|-
 
| PS
 
| PS
Line 201: Line 276:
 
| Resistor Network
 
| Resistor Network
 
|-
 
|-
−
| S
+
| S/SW
 
| Switch
 
| Switch
 
|-
 
|-
Line 215: Line 290:
 
| X
 
| X
 
| Crystal
 
| Crystal
 +
|-
 +
| XF
 +
| External Fuse
 
|}
 
|}
  
 
=Schematics=
 
=Schematics=
−
==Overall==
+
==Grid==
−
*Organize subsystems as follows:
+
*'''Size:''' 0.1 in
−
*Related subsystems should be grouped into a sheet
+
*'''Alt:''' 0.01 in
−
*Each subsystem in a sheet should be boxed clearly, and that box labeled
+
==Sheets==
−
**Use line tool, width 0.006, shortdash, layer 97 info
+
===Overall===
−
**Label font
+
*Group related subsystems into a sheet
−
***Font - vector
+
*Have only 1 frame per sheet
−
***Ratio - 12%
+
===Frames===
−
***Size - 0.25 in
+
*A 11 x 17" frame with the following attributes
−
***Layer - Info
+
**'''TEAM:''' RoboJackets team name
−
**Every sheet should have the following:
+
**'''SCH_DESC:''' Short summary of content in the frame
−
***A frame no bigger than 11 x 17" (8½ x 11” preferred), which should have the following info:
+
**'''REVISION:''' Schematic version
−
***A name
+
*Group related subsystems into boxes
−
***Last edit date
+
**Use Lines
−
***Last edit engineer(s)
+
***'''Width:''' 0.006 in
−
***Schematic version
+
***'''Style:''' shortdash
−
***Page #
+
***'''Layer:''' 97 Info
−
**Frames within a schematic should all be the same size
+
***'''Curve:''' 0
 +
**Label using Text
 +
***'''Size:''' 0.07 in
 +
***'''Ratio:''' 8%
 +
***'''Line Distance:''' 50%
 +
***'''Font:''' proportional
 +
***'''Align:''' bottom-left
 +
***'''Layer:''' 97 Info
 +
===Description===
 +
*Should match the SCH_DESC from the frame
 
==Nets==
 
==Nets==
−
*Every net should have a name if possible
+
===Style===
−
**Use xref tags at 0.05 size
+
*Text
−
*Every bus should have a name and description
+
**'''Size:''' 0.05 in
−
*Every power net should be labeled with the acceptable voltage range and max current at the net driver
+
**'''Ratio:''' 8%
−
*Differentially routed nets should be commented as such as the driver and sink
+
**'''Line Distance:''' 50%
−
*Impedance controlled nets should be commented as such as the driver and sink
+
**'''Font:''' proportional
−
*Power and Ground nets
+
**'''Align:''' bottom-left
−
**Use symbol with appropriate name
+
**'''Layer:''' 97 Info
−
==Configs==
+
===Signals===
−
*Any value computed (e.g. varies by application) from a datasheet should be noted
+
*Should have a name if possible
−
*Any optional parts should be noted
+
*Label every net:
−
*0ohm isolation resistor and 0ohm jumper resistors should be noted
+
**'''Size:''' 0.05
 +
**'''Ratio:''' 8%
 +
**'''Font:''' proportional
 +
**'''Align:''' bottom-left
 +
**'''Layer:''' 95 Names
 +
**'''Xref:''' checked
 +
===Power===
 +
*Use symbols with appropriate name as necessary
 +
*Label with the voltage range and max current at driver  
 +
*Use Text
 +
===Busses===
 +
*Should have a name and description
 +
*Use Text
 +
==Notes==
 +
===Computed Values===
 +
*Note values derived from a datasheet with a short explanation
 +
*Use Text within the box of the part in question
 +
===Specific Parts===
 +
*Note optional parts
 +
*Note 0ohm isolation resistors and 0ohm jumper resistors
 +
*Use Text within the box of the part in question
 
=Boards=
 
=Boards=
−
==Fab House / Validation==
+
==Grid==
−
*Load fab house DRC before place and route
+
*'''Size:''' 1 mm
−
*RoboJackets has slightly conservative DRCs for 2 and 4 layer boards
+
*'''Alt:''' 0.1 mm
 +
==Board Fab==
 +
*Load design rules before placement and routing
 +
**Allows spacing constraints to be known to tool
 +
*Check [https://github.com/RoboJackets/eagle-libraries/tree/master/design%20rules this repo] for common EAGLE DRC files per fab
 
==Placement==
 
==Placement==
−
*Keep analog electronics far from high power electronics
+
===General===
−
*Locate power net status LEDs near power sources
+
*LEDs
−
*Provide adequate spacing for stitching/shielding if needed
+
**Locate power status LEDs near power sources
−
*Verify any mechanical considerations
+
*Noise prevention
−
**Board mounting holes
+
**Keep analog electronics far from high power electronics
−
**Component mounting holes/cutouts
+
**Provide adequate spacing for via stitching/shielding if needed
−
**Use tDoc/bDoc and/or tKeepout/bKeepout for bolt head size to prevent traces near mounting
+
*Decoupling capacitors
−
*Place decoupling capacitors as close to the power pin of the IC as possible
+
**Recommended 1 per power pin on an IC
−
**Smallest values should be closest to pin to minimize parasitic inductance
+
**Place as close as possible to the power pin
 +
**Use multiple if necessary
 +
***Reduces noise
 +
***Place smallest value closest to the pin
 +
===Mechanical Considerations===
 +
*Plan for board mounting holes
 +
**Figure out size of the hole and necessary clearance
 +
**Prevent components and traces from being near bolt heads
 +
*Plan for board cutouts and shape
 +
**Mark these before placement and routing
 +
***Use 51 tDoc / 52 bDoc to indicate cutout
 +
**Prevent components and traces from being near the cutout
 +
*Prevent components and traces from overlapping
 +
**Use 39 tKeepout / 40 bKeepout to block components
 +
**Use 41 tKeepout / 42 bKeepout to block copper and traces
 
==Routing==
 
==Routing==
−
*Avoid minimum trace width where possible
+
===General Practices===
−
**Suggestions: 0.2 to 0.3mm for signals, 0.4 to 0.5mm for power (increase as needed for current rating)
+
*For two layer boards, try to keep components, signals, and power on the top layer and a ground plane on the bottom layer
−
*Avoid minimum trace spacing where possible
+
**Use Polygon
−
*Avoid minimum drill/via size where possible
+
***'''Width:''' 0.2mm
−
**Suggestions: 0.35mm drill, 0.65mm diameter for vias
+
***'''Cap:''' round
−
*Do not split differentially routed pairs unless impedance and arrival time can be matched
+
***'''Layer:''' 16 Bottom
 +
***'''Curve:''' 0
 +
***'''Polygon Pour:''' solid
 +
***'''Spacing:''' 0.05
 +
***'''Isolate:''' 0
 +
***'''Rank:''' 1
 +
***'''Orphans:''' unchecked
 +
***'''Thermals:''' unchecked
 +
*Use extra internal layers when necessary
 +
**Allows for simplified power routing
 +
**Leaves more space for signal traces
 +
**Put power planes internally
 +
***Layer 2 and 15 on 4 layer boards
 +
***Layer 2, 3, 14, and 15 on 6 layer boards
 +
*Route signals orthogonally to avoid cross-talk between different layers (for boards >2 layers)
 +
*Differential signals
 +
**Do not split differentially routed pairs unless impedance and arrival time can be matched
 +
*High frequency
 +
**High frequency signals should have continuous low impedance return path directly beneath trace.  
 +
**Keep high frequency signals isolated from other signals to minimize crosstalk
 +
===Traces===
 +
*In general
 +
**'''Style:''' continuous
 +
**'''Cap:''' round
 +
**'''Curve:''' 0
 +
*Signals
 +
**'''Width:''' 0.3mm
 +
*Power
 +
**'''Width:''' 0.5mm (increase as necessary for [https://www.4pcb.com/trace-width-calculator.html current requirements])
 +
*Avoid minimum sizing (based on the DRC) when possible
 +
===Vias===
 +
*At minimum
 +
**'''Diameter:''' 0.65mm
 +
**'''Drill:''' 0.35mm
 +
**'''Shape:''' round
 +
**'''Layer:''' 1-16
 +
*Avoid minimum sizing (based on the DRC) when possible
 
*Avoid vias on signals above 1GHz
 
*Avoid vias on signals above 1GHz
 
*Use the same number of vias on differentially routed traces
 
*Use the same number of vias on differentially routed traces
−
*For two layer boards, try to keep component, signal, and power on the top layer and ground return on the bottom layer
 
−
*High frequency signals should have continuous low impedance return path directly beneath trace.
 
−
*Keep high frequency signals isolated from other signals to minimize crosstalk
 
−
*Route signals orthogonally to avoid cross-talk
 
 
==Silkscreen==
 
==Silkscreen==
−
*This is far more important than most people realize and can take a significant amount of time to get right. A good silkscreen makes a board easier to use, easier to debug, and harder to break.
+
*Far more important than most people realize and can take a significant amount of time to get right
−
===Meta===
+
*Makes a board easier to use, easier to debug, and harder to break
−
*Have at least a "vMAJOR.minor" version label on the board
+
===Style===
−
*Have your team name and year (optionally month, Ubuntu style) on the board
+
*Text
−
*Have your team logo on the board
+
**'''Size:''' 1 mm (at minimum)
−
*Have a filled white square to write in an instance ID
+
**'''Ratio:''' 8% (Important text can be bolded using 15%)
−
**Recommended if more than three boards will be fabricated
+
**'''Line Distance:''' 50%
−
**e.g. can say "board #2 is broken", there is a "2" written on the white square
+
**'''Font:''' vector
−
**Cover ink with Kapton tape
+
**'''Layer:''' 21 tPlace / 22 bPlace
−
*Don’t place them on vias (even tented vias) unless absolutely unavoidable
+
*Markings (anything not already in footprints)
−
===Components & Connectors===
+
**Will be in final board output
−
*Set default line width to 0.2mm
+
**Use Lines
 +
***'''Width:''' 0.2 mm
 +
***'''Style:''' continuous
 +
***'''Layer:''' 21 tPlace / 22 bPlace
 +
*Extra Details
 +
**Will not be in final board output
 +
**Capture more details, extensions beyond outline, etc
 +
**Use Lines
 +
***'''Width:''' 0.2 mm
 +
***'''Style:''' continuous
 +
***'''Layer:''' 51 tDocu / 52 bDocu
 +
*Measurements
 +
**Will not be in final board output
 +
**Useful to mark critical distances
 +
**Can mark outer board dimensions
 +
**Use Dimension
 +
***'''Size:''' 2 mm
 +
***'''Ratio:''' 8% (Important dimensions can be bolded using 15%)
 +
***'''Layer:''' 47 Measures
 +
***'''DType:''' parallel
 +
***'''Line Width:''' 0.2mm
 +
***'''Ext. Line Width:v auto
 +
***'''Ext. Line Length:''' auto
 +
***'''Ext. Line Offset:''' auto
 +
***'''Unit:''' mm
 +
***'''Precision:''' 3
 +
***'''Show unit:''' checked
 +
===Labels===
 
*Label all power inputs with name and voltage (current optional)
 
*Label all power inputs with name and voltage (current optional)
 
*Label all connectors with name
 
*Label all connectors with name
−
*Label all switches with position values
+
*Label all switches with position values (e.g. on or off)
−
*Label all debug LEDs
+
*Label all debug LEDs (e.g. MCU Status)
−
*Label all fuses with current rating (type optional)
+
*Label all fuses with current rating
−
===Font===
+
===General===
−
*All font should be vector rendered
+
*Aesthetics
−
*All font should be ratio 8%, unless made bold for end user benefit
+
**Don’t place silkscreen on vias (even tented vias) unless absolutely unavoidable
−
*Component font size should be "1"
+
**Have your team logo on the board (e.g. RoboBuzz)
−
**e.g. R45, Q1, etc.
+
*Versioning
−
*Layer - t/bPlace
+
**Have a "vMAJOR.minor" version text label on the board (e.g. v2.1)
 +
**Have your team name and year on the board (e.g. RoboCup 2020)
 +
*Board ID
 +
**White square to allow for a board ID (e.g. written 2 means board 2)
 +
**Recommended if more than three boards will be fabricated
 +
**Use Rectangle
 +
***Make width and height 5mm by 5mm (minimum)
 +
***'''Layer:''' 21 tPlace / 22 bPlace
  
 
[[Category: Electrical]]
 
[[Category: Electrical]]

Latest revision as of 20:17, 6 July 2021

Part Creation

Symbol

Grid

  • Size: 0.1 in
  • Alt: 0.01 in

Name

  • Should be manufacturer part/family number (eg. ATTINY167-SU)

Description

  • Leave blank

Style

  • Origin
    • Center origin (crosshair) on symbol center
  • Text
    • Keep text horizontal
    • Size: 0.07 in
    • Line Distance: 50%
    • Font: proportional
  • Name
    • Locate in top left of symbol
    • Align: bottom-left
    • Layer: 95 Names
    • Value: >NAME
  • Value
    • Locate in bottom-left of symbol
    • Align: top-left
    • Layer: 96 Values
    • Value: >VALUE
  • Outline
    • Use Lines
      • Width: 0.01 in
      • Style: continuous
      • Layer: 94 Symbol
      • Curve: 0
    • Try to have a length/width that is a 0.1 in multiple (eg. 0.4 in by 0.4 in)

Functionality

  • Pins
    • Label pins to allow the symbol to be applied to parts in similar families
    • Name: Based on part datasheet
    • Direction: pas (passive)
    • Swap Level: 0
    • Length: middle
    • Function: none
    • Visible: both
  • Pin Placement
    • Power (VCC): top left
    • Ground (GND): bottom right
    • Inputs: left edge
    • Outputs: right edge
  • Passive Pins
    • Specifically resistors, capacitors, inductors, fuses, diodes
    • Visible: off
  • Connector Pins
    • Try to reuse an existing symbol for the size of connector
    • If need to make a new one, for pins:
      • Visible: pad
  • Decimal Labeling
    • For fractional values include the decimal point (eg. 3.3V, 4.5K)

Footprint

Grid

  • Size: 1 mm
  • Alt: 0.1 mm

Name

  • Should be manufacturer footprint name (eg. SOIC-20)

Description

  • Link to datasheet for part/family for pad layout

Style

  • Origin
    • Center origin (crosshair) on footprint center
  • Text
    • Keep text horizontal
    • Size: 1 mm
    • Ratio: 10%
    • Line Distance: 50%
    • Font: vector
  • Name
    • Locate in top left of footprint
    • Align: bottom-left
    • Layer: 25 tNames
    • Value: >NAME
  • Value
    • Locate in bottom-left of symbol
    • Align: top-left
    • Layer: 27 tValues
    • Value: >VALUE
  • Outline
    • Use Lines
      • Width: 0.2 mm
      • Style: continuous
      • Layer: 21 tPlace
    • Draw package outline per part/family datasheet
    • Used for part placement
  • Keepout
    • Use Rectangles
      • Layer: 39 tKeepout
    • Size 0.1 mm larger than the package
    • Used to prevent overlapping parts
  • Details
    • Capture more part details, extensions beyond outline, etc
    • Use
      • Width: 0.2 mm
      • Style: continuous
      • Layer: 51 tDocu

Functionality

  • Pad (Through-hole)
    • Name: name based on datasheet pin number
    • Diameter: auto
    • Drill: size based on datasheet
    • Shape: circle
    • Locked: unchecked
    • Thermals: checked
    • Stop: checked
    • First: unchecked
  • Smd (Surface Mount)
    • Name: name based on datasheet pin number
    • Smd Size: size based on datasheet
    • Layer: 1 Top (usually)
    • Roundness: 0%
    • Locked: unchecked
    • Thermals: checked
    • Stop: checked
    • Cream: checked
  • Polarity Indication
    • Through-hole
      • Make pin 1 visually different
      • Shape: square
    • Indicate polarity, when necessary
      • Prevents backwards installation
      • Direction or cathode indicators for diodes
      • Stripe or plus-minus for capacitors
    • Indicate Pin 1 for ICs
      • Use a circle (dot)
        • Width: 0 mm
        • Layer: 21 tPlace
        • Radius: 0.2 mm (at minimum)
    • Avoid overlapping pads with silkscreen, cut a section out

Device

Name

  • Should be manufacturer part number (eg. ATTINY167-SU)
  • Wildcards
    • Allows devices with multiple technologies (specifications) or packages
      • Uses wildcards in device name
      • Technology Name: *
      • Package Name: ?
    • Example
      • Regulator with two voltage (3.3V and 1.8V) technologies
        • AP2138N-3.3TRG1 for 3.3V
        • AP2138N-1.8TRG1 for 1.8V
        • Becomes AP2138N-*TRG1 with technology 3.3 and 1.8

Description

  • One sentence part function overview (valid for all variants)
  • Datasheet link

Value

  • Off unless its a passive part (resistors, capacitors, inductors, fuses, diodes)
  • If its a specific passive part with a value, add an attribute
    • Name: VALUE
    • Value: the value
    • Type: variable

Symbol

  • Use specific symbol for that part/family
  • Connectors are an exception
    • Generic symbol used for all connectors of a certain size

Footprint

  • Use specific footprint if unique
  • Try to reuse a footprint if it matches

Attribute (non-Passives)

  • Part number
    • Name: DKPN
    • Value: the Digi-Key Part Number (eg. ATTINY167-SU-ND)
    • Type: variable

Attribute (Passives)

  • Part number
    • Name: DKPN
    • Value: blank unless specific to part
    • Type: variable
  • Resistors
    • Should have tolerance and power ratings that is blank by default
    • Value is for resistance only
    • Tolerance
      • Name: TOL
      • Value: blank unless specific to part
      • Type: variable
    • Power
      • Name: POW
      • Value: blank unless specific to part
      • Type: variable
  • Capacitors
    • Should have tolerance and voltage ratings that is blank by default
    • Value is for capacitance only
    • Tolerance
      • Name: TOL
      • Value: blank unless specific to part
      • Type: variable
    • Voltage
      • Name: VOLT
      • Value: blank unless specific to part
      • Type: variable
  • Inductors
    • Should have tolerance and current ratings that is blank by default
    • Value is for inductance only
    • Tolerance
      • Name: TOL
      • Value: blank unless specific to part
      • Type: variable
    • Current
      • Name: CUR
      • Value: blank unless specific to part
      • Type: variable
  • Fuses
    • Value is for current rating
  • Diodes
    • LEDs
      • Value should be color
    • Normal Diode
      • Value should be reverse voltage
    • TVS Diode
      • Value should be [Working Voltage]-[Breakdown Voltage] (e.g. 8V-8.5V)

Prefix

Chart for Prefix Designators
Letter Part Type
A Separate Assembly or Subassembly
C Capacitor
D Diode or LED
F Fuse
FB Ferrite bead
J Jack or Connector (least moveable connection part)
JP Jumper
K Relay or Contactor
L Inductor
LS/BZ Loudspeaker or Buzzer
M Motor
P Plug (most moveable connection part)
POT Potentiometer
PS Power Supply
Q Transistor
R Resistor
RN Resistor Network
S/SW Switch
T Transformer
TP Test Point
U Integrated Circuit
X Crystal
XF External Fuse

Schematics

Grid

  • Size: 0.1 in
  • Alt: 0.01 in

Sheets

Overall

  • Group related subsystems into a sheet
  • Have only 1 frame per sheet

Frames

  • A 11 x 17" frame with the following attributes
    • TEAM: RoboJackets team name
    • SCH_DESC: Short summary of content in the frame
    • REVISION: Schematic version
  • Group related subsystems into boxes
    • Use Lines
      • Width: 0.006 in
      • Style: shortdash
      • Layer: 97 Info
      • Curve: 0
    • Label using Text
      • Size: 0.07 in
      • Ratio: 8%
      • Line Distance: 50%
      • Font: proportional
      • Align: bottom-left
      • Layer: 97 Info

Description

  • Should match the SCH_DESC from the frame

Nets

Style

  • Text
    • Size: 0.05 in
    • Ratio: 8%
    • Line Distance: 50%
    • Font: proportional
    • Align: bottom-left
    • Layer: 97 Info

Signals

  • Should have a name if possible
  • Label every net:
    • Size: 0.05
    • Ratio: 8%
    • Font: proportional
    • Align: bottom-left
    • Layer: 95 Names
    • Xref: checked

Power

  • Use symbols with appropriate name as necessary
  • Label with the voltage range and max current at driver
  • Use Text

Busses

  • Should have a name and description
  • Use Text

Notes

Computed Values

  • Note values derived from a datasheet with a short explanation
  • Use Text within the box of the part in question

Specific Parts

  • Note optional parts
  • Note 0ohm isolation resistors and 0ohm jumper resistors
  • Use Text within the box of the part in question

Boards

Grid

  • Size: 1 mm
  • Alt: 0.1 mm

Board Fab

  • Load design rules before placement and routing
    • Allows spacing constraints to be known to tool
  • Check this repo for common EAGLE DRC files per fab

Placement

General

  • LEDs
    • Locate power status LEDs near power sources
  • Noise prevention
    • Keep analog electronics far from high power electronics
    • Provide adequate spacing for via stitching/shielding if needed
  • Decoupling capacitors
    • Recommended 1 per power pin on an IC
    • Place as close as possible to the power pin
    • Use multiple if necessary
      • Reduces noise
      • Place smallest value closest to the pin

Mechanical Considerations

  • Plan for board mounting holes
    • Figure out size of the hole and necessary clearance
    • Prevent components and traces from being near bolt heads
  • Plan for board cutouts and shape
    • Mark these before placement and routing
      • Use 51 tDoc / 52 bDoc to indicate cutout
    • Prevent components and traces from being near the cutout
  • Prevent components and traces from overlapping
    • Use 39 tKeepout / 40 bKeepout to block components
    • Use 41 tKeepout / 42 bKeepout to block copper and traces

Routing

General Practices

  • For two layer boards, try to keep components, signals, and power on the top layer and a ground plane on the bottom layer
    • Use Polygon
      • Width: 0.2mm
      • Cap: round
      • Layer: 16 Bottom
      • Curve: 0
      • Polygon Pour: solid
      • Spacing: 0.05
      • Isolate: 0
      • Rank: 1
      • Orphans: unchecked
      • Thermals: unchecked
  • Use extra internal layers when necessary
    • Allows for simplified power routing
    • Leaves more space for signal traces
    • Put power planes internally
      • Layer 2 and 15 on 4 layer boards
      • Layer 2, 3, 14, and 15 on 6 layer boards
  • Route signals orthogonally to avoid cross-talk between different layers (for boards >2 layers)
  • Differential signals
    • Do not split differentially routed pairs unless impedance and arrival time can be matched
  • High frequency
    • High frequency signals should have continuous low impedance return path directly beneath trace.
    • Keep high frequency signals isolated from other signals to minimize crosstalk

Traces

  • In general
    • Style: continuous
    • Cap: round
    • Curve: 0
  • Signals
    • Width: 0.3mm
  • Power
  • Avoid minimum sizing (based on the DRC) when possible

Vias

  • At minimum
    • Diameter: 0.65mm
    • Drill: 0.35mm
    • Shape: round
    • Layer: 1-16
  • Avoid minimum sizing (based on the DRC) when possible
  • Avoid vias on signals above 1GHz
  • Use the same number of vias on differentially routed traces

Silkscreen

  • Far more important than most people realize and can take a significant amount of time to get right
  • Makes a board easier to use, easier to debug, and harder to break

Style

  • Text
    • Size: 1 mm (at minimum)
    • Ratio: 8% (Important text can be bolded using 15%)
    • Line Distance: 50%
    • Font: vector
    • Layer: 21 tPlace / 22 bPlace
  • Markings (anything not already in footprints)
    • Will be in final board output
    • Use Lines
      • Width: 0.2 mm
      • Style: continuous
      • Layer: 21 tPlace / 22 bPlace
  • Extra Details
    • Will not be in final board output
    • Capture more details, extensions beyond outline, etc
    • Use Lines
      • Width: 0.2 mm
      • Style: continuous
      • Layer: 51 tDocu / 52 bDocu
  • Measurements
    • Will not be in final board output
    • Useful to mark critical distances
    • Can mark outer board dimensions
    • Use Dimension
      • Size: 2 mm
      • Ratio: 8% (Important dimensions can be bolded using 15%)
      • Layer: 47 Measures
      • DType: parallel
      • Line Width: 0.2mm
      • Ext. Line Width:v auto
      • Ext. Line Length: auto
      • Ext. Line Offset: auto
      • Unit: mm
      • Precision: 3
      • Show unit: checked

Labels

  • Label all power inputs with name and voltage (current optional)
  • Label all connectors with name
  • Label all switches with position values (e.g. on or off)
  • Label all debug LEDs (e.g. MCU Status)
  • Label all fuses with current rating

General

  • Aesthetics
    • Don’t place silkscreen on vias (even tented vias) unless absolutely unavoidable
    • Have your team logo on the board (e.g. RoboBuzz)
  • Versioning
    • Have a "vMAJOR.minor" version text label on the board (e.g. v2.1)
    • Have your team name and year on the board (e.g. RoboCup 2020)
  • Board ID
    • White square to allow for a board ID (e.g. written 2 means board 2)
    • Recommended if more than three boards will be fabricated
    • Use Rectangle
      • Make width and height 5mm by 5mm (minimum)
      • Layer: 21 tPlace / 22 bPlace
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