EAGLE Style Guide

2020-07-11T04:33:44Z

Asrinivasan77:

=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
**'''Ratio:''' 8%
**'''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:''' 8%
**'''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:''' 26 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:''' Tolerance
***'''Value:''' blank unless specific to part
***'''Type:''' variable
**Power
***'''Name:''' Power
***'''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:''' Tolerance
***'''Value:''' blank unless specific to part
***'''Type:''' variable
**Voltage
***'''Name:''' Voltage
***'''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:''' Tolerance
***'''Value:''' blank unless specific to part
***'''Type:''' variable
**Current
***'''Name:''' Current
***'''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===
{| class="wikitable"
|+ Chart for Designation
|-
! 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)
|-
| 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=
==Overall==
*Organize subsystems as follows:
*Related subsystems should be grouped into a sheet
*Each subsystem in a sheet should be boxed clearly, and that box labeled
**Use line tool, width 0.006, shortdash, layer 97 info
**Label font
***Font - vector
***Ratio - 12%
***Size - 0.25 in
***Layer - Info
**Every sheet should have the following:
***A frame no bigger than 11 x 17" (8½ x 11” preferred), which should have the following info:
***A name
***Last edit date
***Last edit engineer(s)
***Schematic version
***Page #
**Frames within a schematic should all be the same size
==Nets==
*Every net should have a name if possible
**Use xref tags at 0.05 size
*Every bus should have a name and description
*Every power net should be labeled with the acceptable voltage range and max current at the net driver
*Differentially routed nets should be commented as such as the driver and sink
*Impedance controlled nets should be commented as such as the driver and sink
*Power and Ground nets
**Use symbol with appropriate name
==Configs==
*Any value computed (e.g. varies by application) from a datasheet should be noted
*Any optional parts should be noted
*0ohm isolation resistor and 0ohm jumper resistors should be noted
=Boards=
==Fab House / Validation==
*Load fab house DRC before place and route
*RoboJackets has slightly conservative DRCs for 2 and 4 layer boards
==Placement==
*Keep analog electronics far from high power electronics
*Locate power net status LEDs near power sources
*Provide adequate spacing for stitching/shielding if needed
*Verify any mechanical considerations
**Board mounting holes
**Component mounting holes/cutouts
**Use tDoc/bDoc and/or tKeepout/bKeepout for bolt head size to prevent traces near mounting
*Place decoupling capacitors as close to the power pin of the IC as possible
**Smallest values should be closest to pin to minimize parasitic inductance
==Routing==
*Avoid minimum trace width where possible
**Suggestions: 0.2 to 0.3mm for signals, 0.4 to 0.5mm for power (increase as needed for current rating)
*Avoid minimum trace spacing where possible
*Avoid minimum drill/via size where possible
**Suggestions: 0.35mm drill, 0.65mm diameter for vias
*Do not split differentially routed pairs unless impedance and arrival time can be matched
*Avoid vias on signals above 1GHz
*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==
*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.
===Meta===
*Have at least a "vMAJOR.minor" version label on the board
*Have your team name and year (optionally month, Ubuntu style) on the board
*Have your team logo on the board
*Have a filled white square to write in an instance ID
**Recommended if more than three boards will be fabricated
**e.g. can say "board #2 is broken", there is a "2" written on the white square
**Cover ink with Kapton tape
*Don’t place them on vias (even tented vias) unless absolutely unavoidable
===Components & Connectors===
*Set default line width to 0.2mm
*Label all power inputs with name and voltage (current optional)
*Label all connectors with name
*Label all switches with position values
*Label all debug LEDs
*Label all fuses with current rating (type optional)
===Font===
*All font should be vector rendered
*All font should be ratio 8%, unless made bold for end user benefit
*Component font size should be "1"
**e.g. R45, Q1, etc.
*Layer - t/bPlace

[[Category: Electrical]]

EAGLE Style Guide

2020-07-11T04:08:23Z