Shit Parameters

DO NOT ADD THESE. WE DON’T WANT THEM

• Datasheets (these often go out of date, so we require pulling from online)

• RoHS Compliant (not relevant)

• Reach SVHC Compliant (not relevant)

• Packaging (not relevant)

Note
When importing parameters, the above often are suggested. Make sure to uncheck them.

Symbols

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Symbol Layout

Symbols should use imperial spacing at 100 mils.

If a more detailed symbol isn’t available, footprints should be implemented using the Altium default yellow rectangle with “small” red outline. Pins should be spaced by one 100 mil grid spacing.

Pin designators should be hidden and pin names should exactly match the datasheet (with the exception of characters that Altium doesn’t allow).

Pin arrangement can be either matching the physical layout or optimized for schematic routing (place pins as needed to avoid messy wires).

Designators

Utilize common designators for symbols. The hard-set definition we use is Appendix F of IEEE-315:

View file
name IEEE-315-1975_AnnexF.pdf

The right side column is what we utilize, when applicable.

All designator letters should be followed by “?”, as this is the wildcard for auto-generating designators. For example “D?” for diodes, “J?” for connectors, “R?” for resistors.

Footprints

All layers can adjust line width to be proportional to component size. Around 5 mils / 0.15mm is often a good starting point.

Layer Pair Setup

The following are the required layer pairs names and numbers as well as what to put in each.

Info
These are all standard types. You can avoid typing them by selecting out of the dropdown first.

Assembly

• Should be a 3D model downloaded from the manufacturer or other trusted site

• A 3D extrusion is allowable to approximate if no CAD can be found

• Additional physical assembly details can be included if required (designator indicators or other features)

Component Outline

Must match the physical outline of the component. This can be traced from 3D body, if the body is accurate. If legs are present, the legs should be disregarded (only trace the plastic/ceramic body)

Component Center

A crosshair must be added to all components. This consists of just two lines intersecting to create plus sign.

The component center should be placed at the center of all component pins.

The lines should default to 30 mils / 0.8 mm. This may be decreased or increased if the component is foolishly smaller or larger than these extents.

Courtyard

Collision box for placing components. This is a boundary that should define how much clearance is recommended between components.

Recommended: 10 mils / 0.25 mm

Courtyards should be defined from the physical bounds of the component and pads. Silkscreen may be outside the courtyard if desired.

Pin 1 Designation

Pin one is usually indicated in the datasheet. If not, select the top left or top right corner from the footprint.
Pin one must be indicated in silkscreen. By default, this should be a circle next to pin one.

Pin one ideally is also indicated via pads with a rectangular/square pad (with the other pads being ovular/circular).

3D Model

All footprints must include a 3D model.

If manufacturer CAD is not available, add an extruded model and color it to a representative hue.

Origin

All layouts and footprints have an origin. This is where the coordinate system is zeroed from.

The origin may be moved throughout the layout process but when complete must be set to either the origin of the datasheet dimensions or the center of the component.

Schematics

All schematic sheets must use the NER template. Tabloid is the default, but Letter size is also available.

Info
These are set via page properties. Click in blank space then open the properties panel. The https://nerdocs.atlassian.net/wiki/spaces/NER/pages/136314883/Schematic+Capture#Schematic-Templates page has further directions if needed.

Organization & Hierarchy

Projects requiring multiple sheets should implement a hierarchical structure, utilizing a block-diagram style top sheet.

...

It is preferential to keep a design entirely on the top sheet, if it is small enough.

Functional sections on all pages should then be designated using medium red dashed lines to define boxes.

...

All schematics must be organized logically. This is typically either by placing in order of power and signal flow (inputs/supplies to the left, to outputs/loads on the right) or, for TS-GLV projects, by organizing according to isolation, placing all isolation barriers along a single line.

Style Guidelines

Schematics should default to a 100 mils grid system. The grid may be reduced for placing certain components, but components and wires must be aligned to a 100 mils grid.

Signal Routing

Within functional sections of the schematic, it is recommended to utilize wires to establish connections. For longer runs, or within densely connected regions, it is best to use Net Labels. Generally, wire routing just needs to be kept readable, however the designer thinks that is best achieved.

All connections of significance should be net labeled, even if connected via wire.

Wires must be stepped away from connections by at least 1 grid spacing (100 mils)

{image of good and bad}

Four way connections must be avoided.

{image of bad and good}

Net Labels

Net labels should be used anywhere they make sense, both for connections and for just labeling purposes.

Net labels should be in full caps with underscores to separate words and suffixes.

Acronyms may be used if full name would be excessively long. A note should be added to explain acronyms if they are not self explanatory.

Power & GND Ports

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All power nets must be implemented using power ports.

The BAR power port must be used for all supply voltage nets. This includes positive and negative rails.

The GND port must be used for all GLV ground/chassis connections.

The SIGNAL ground port may be used in non-GLV ground systems. This primarily arises in isolated systems.

Communication Busses

Bussed signals, such as CAN, SPI, I2C, etc should utilize harnesses.

...

Addressed Devices (I2C)

Devices with addresses set in hardware must have their address stated above the component in blue text.

...

Component Placement

Components should be placed on a 100 mils grid.

Certain parameters should be displayed for every type of component. These may be modified in certain contexts if shown data is completely irrelevant. I.e. resistors used for logic may not need to show power rating.

If no parameters are shown, the MPN should be shown instead.

Output Current (A)

Shit Parameters

DO NOT ADD THESE. WE DON’T WANT THEM

• Datasheets (these often go out of date, so we require pulling from online)

• RoHS Compliant (not relevant)

• Reach SVHC Compliant (not relevant)

• Packaging (not relevant)

Note
When importing parameters, the above often are suggested. Make sure to uncheck them.

What Value to Use

Numerical Values

All parameters must be filled in using values from normal/recommended operation. This means the “Absolute Max” table or values should not be used.

If one parameter field is provided and the datasheet provides typical, min/max, and absolute min/max, think about what is most informative when searching for components for a new design. Typically, the minimum/maximum of normal range!

Case/Package Value

Digikey may provide multiple different values for this field. Our protocol is to first check if we have an existing footprint for the component. If so, enter the standard footprint name that was used. If not, use whichever name is most commonized (avoid manufacturer proprietary names).

Symbols

...

Symbol Layout

Symbols should use imperial spacing at 100 mils.

If a more detailed symbol isn’t available, footprints should be implemented using the Altium default yellow rectangle with “small” red outline. Pins should be spaced by one 100 mil grid spacing.

Pin designators should be hidden and pin names should exactly match the datasheet (with the exception of characters that Altium doesn’t allow).

Pin arrangement can be either matching the physical layout or optimized for schematic routing (place pins as needed to avoid messy wires).

Designators

Utilize common designators for symbols. The hard-set definition we use is Appendix F of IEEE-315:

View file
name IEEE-315-1975_AnnexF.pdf

The right side column is what we utilize, when applicable.

All designator letters should be followed by “?”, as this is the wildcard for auto-generating designators. For example “D?” for diodes, “J?” for connectors, “R?” for resistors.

...

Properties

The component type must be set when applicable. This drop down allows you to define components as non-BOM items, such as mounting holes, test points, etc. We primarily use Standard, Net Tie (No BOM), and Standard (No BOM).

The Designator must be shown, however the Comment typically is hidden. The comment field determines if the component part number will be shown by default.

Footprints

All footprints must be modeled such that the component is installed on the top side of the board (footprints are a top view) and such that pin 1 is towards the top left.

All layers can adjust line width to be proportional to component size. 5 mils / 0.12mm is a good starting point.

Layer Pair Setup

The following are the required layer pairs names and numbers as well as what to put in each.

Info
These are all standard types. You can avoid typing them by selecting out of the dropdown first.

As mentioned above, we recommend a line width for all primitives of 5 mils / 0.12 mm. This can be adjusted proportionally to the overall component size if desired to avoid obscuring detail.

Assembly

Should be a 3D model downloaded from the manufacturer or other trusted site. A 3D extrusion is allowable to approximate if no CAD can be found.

Additional physical assembly details can be included if required (designator indicators or other assembly features). For context on what is acceptable, this is a layer that is purely used for reference by the company assembling the board. We typically only add a 3D model.

Component Outline

Must match the physical outline of the component. This can be traced from 3D body, if the body is accurate.

Note
You must verify the 3D body against the datasheet using the measure tool. We have had multiple instances of people tracing the wrong shape, due to complex models, or even wrong dimensions!

If this is a legged component, the legs should be disregarded (only trace the plastic/ceramic body)

Component Center

A crosshair must be added to all components. This consists of just two lines intersecting to create plus sign.

The component center should be placed at the center of all component pins.

The lines should default to 30 mils / 0.8 mm in length. This may be decreased or increased if the component is foolishly smaller or larger than these extents.

Courtyard

Collision box for placing components. This is a boundary that should define how much clearance is recommended between components.

Recommended spacing: 10 mils / 0.25 mm

Courtyards should be defined from the physical bounds of the component and pads. Silkscreen may be outside the courtyard if desired.

Pad Guidelines

Duplicate pads (pads representing the same net) should utilize unique identifiers, and be remapped at the component level. There can be an exception to this for mounting pads, however the trend for Altium seems to be to move fully to unique pad numbers.

Tolerance data is not necessary for any of our work. It should be left blank.

Solder mask relief must be set to “Rule.” Exceptions should only be made if a component datasheet requests exact values.

Through Holes

Annular ring (the difference between pad radius and hole radius) should be X mils / X mm. Fabricators specify a smaller size which we can use, but we recommend this size for ease of hand solderability.

Mounting & GND Pads

If a component requires additional pads that are not regular electrical connections, they must be defined as “GND” or as “MNT” dependent on purpose of the pad. They may be MNT1, MNT2, etc to keep unique identifiers.

Pin 1 Designation

Pin one is usually indicated in the datasheet. If not, select the top left or top right corner from the footprint.

Pin one must be indicated in silkscreen. By default, this should be a circle next to pin one. The circle should be 20 mils / 0.5 mm in diameter.

Pin one ideally is also indicated via pads with a rectangular/square pad (with the other pads being ovular/circular). This is most typical in through-hole components.

3D Model

All footprints must include a 3D model. If manufacturer CAD is not available, add an extruded model and color it to a representative hue.

Origin

All layouts and footprints have an origin. This is where the coordinate system is zeroed from.

The origin may be moved throughout the layout process but when complete must be set to either the origin of the datasheet dimensions or the center of the component.

Schematics

All schematic sheets must use the NER template. Tabloid is the default, but Letter size is also available.

Info
These are set via page properties. Click in blank space then open the properties panel. The https://nerdocs.atlassian.net/wiki/spaces/NER/pages/136314883/Schematic+Capture#Schematic-Templates page has further directions if needed.

Organization & Hierarchy

Projects requiring multiple sheets should implement a hierarchical structure, utilizing a block-diagram style top sheet.

...

It is preferential to keep a design entirely on the top sheet, if it is small enough.

Functional sections on all pages should then be designated using medium red dashed lines to define boxes.

...

All schematics must be organized logically. This is typically either by placing in order of power and signal flow (inputs/supplies to the left, to outputs/loads on the right) or, for TS-GLV projects, by organizing according to isolation, placing all isolation barriers along a single line.

Style Guidelines

Schematics should default to a 100 mils grid system. The grid may be reduced for placing certain components, but components and wires must be aligned to a 100 mils grid.

Signal Routing

Within functional sections of the schematic, it is recommended to utilize wires to establish connections. For longer runs, or within densely connected regions, it is best to use Net Labels. Generally, wire routing just needs to be kept readable, however the designer thinks that is best achieved.

All connections of significance should be net labeled, even if connected via wire.

Wires must be stepped away from connections by at least 1 grid spacing (100 mils)

...

Four way connections must be avoided.

...

Net Labels

Net labels should be used anywhere they make sense, both for connections and for just labeling purposes.

Net labels should be in full caps with underscores to separate words and suffixes.

Acronyms may be used if full name would be excessively long. A note should be added to explain acronyms if they are not self explanatory.

All voltage rails should follow the below guidelines.

...

Power & GND Ports

All power nets must be implemented using power ports.

All power nets should be labeled using decimal-less notation. Examples are:

• +3V3 = Positive 3.3V

• +1V8 = Positive 1.8V

• +48V = Positive 48V

• -5V = Negative 5V

The BAR power port must be used for all supply voltage nets. This includes positive and negative rails.

The GND port must be used for all GLV ground/chassis connections.

The SIGNAL ground port may be used in non-GLV ground systems. This primarily arises in isolated systems.

Communication Busses

Bussed signals, such as CAN, SPI, I2C, etc should utilize harnesses.

...

Addressed Devices (I2C)

Devices with addresses set in hardware must have their address stated above the component in blue text.

...

Component Placement

Components should be placed on a 100 mils grid.

Certain parameters should be displayed for every type of component. These may be modified in certain contexts if shown data is completely irrelevant. I.e. resistors used for logic may not need to show power rating.

If no parameters are shown, the MPN should be shown instead.

Expand
title Parameters to display
Component Type Parameters Shown Amplifiers Audio Batteries BJTs Capacitors Chokes Clock & Timing Comparators Connectors Crystals & Oscillators Custom Development Boards Diodes Embedded Fuses Gate Drivers Hardware Heat Sinks Inductors Integrated Circuits Interface Isolators LED Logic Memory MOSFETs Optoisolators PMIC Potentiometers Power Supply Relays Resistors Sensors SSRs Switches Test & Measurement Transformers TVS Diodes Voltage Regulator

Info
Altium should be configured to show the correct parameters automatically. Let the Chief EE know if any component types have errors.

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