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title: "OreSat C3 Card" subtitle: | Fabrication and Assembly Information
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About this Board

Board Description

The C3 ("Command, Control, and Communications") card is the main on-board computer (OBC) / housekeeping unit (HKU) / Command and Data Handling (CDH) subsystem for the open source OreSat CubeSat system. The C3 card:

• Connects to the backplane with a main connector and two RF ports
• Has an L band radio receiver based on the AT86RF215.
• Has a UHF radio transceiver based on the AT86RF215
• Has a radiation tolerant watchdog timer (with a cheap commercial replacement if you're not going to orbit)
• Controls the OreSat Power Domain (OPD), which turns on and off and controls other cards
• Talks to both CAN OreSat CAN busses

Documentation Links

• C3 hardware Git repository: https://github.com/oresat/oresat-c3-hardware
• C3 software Git reposity: https://github.com/oresat/oresat-c3-software
• TODO: C3 Design Notes + Design Review Notes

Documentation Files

Filename	Notes
README.pdf	This README file
PROJECT-NAME-outline.dxf	Board outline (with holes) in DXF format
PROJECT-NAME-pcba.step	3D model of PCBA (with components)
PROJECT-NAME-render-bot.jpg	Render of the top of the 3D model
PROJECT-NAME-render-bot.jpg	Render of the bottom of the 3D model
PROJECT-NAME-schematic.pdf	PDF of board schematics

Contact Information

• Website: https://www.oresat.org/
• Email: [email protected]
• Instagram: @pdxaerospace

Board Renders

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Printed Circuit Board (PCB) Fabrication Information

Board Info

• 4 layer board
• Bounding box is 99.8 x 94.6 mm (3.93 x 3.72 in)
• Board thickness is 1.59 mm (0.063 inch)
• Important: See Materials and Stack Up sections below

Board Requirements

• Design Rules
  • Minimum Trace / Space design rules
    • Outer layers: 0.127 mm (5.0 mil) / 0.127 mm (5.0 mil)
    • Inner layers: 0.127 mm (5.0 mil) / 0.127 mm (5.0 mil)
  • Outer dimension router tolerance: +/- 0.254 mm (10.0 mil)
  • Hole placement tolerance: +/- 0.075 mm (3.0 mil)
  • Inner tab routed slot tolerance: +/- 0.254 mm (10.0 mil)
• Drills
  • Drill Positional Tolerance: 0.051 mm (2.0 mil)
  • Drill Size tolerance: +/- 0.064 mm (2.5 mil)
• Plated/Un-plated holes
  • There are 6 un-plated (NPT) holes
  • There are 1477 plated through (PTH) holes
  • PTH minimum diameter: 0.254 mm (10 mil)
  • PTH minimum annulus: 0.102 mm (4 mil) radius
• Outline/Routing
  • Requires a 1.0 mm or smaller diameter routing bit
• Slots
  • There are no slots.
• Cutouts
  • There are no cutouts
• There are 3 fiducials on the top layer.
• Panel tabs ("mouse bites")
  • Card edges must be smooth; no mouse bites or other intrusions into the card outline.
  • If external mouse bites are required, minimize and customer will remove by hand before assembly.
• If not otherwise specified, build to IPC 6012 Class 2 or better.

Materials

• Controlled impedance
  • The stackup is critical for the performance of high speed signals on this board.
  • As long as the stackup is controlled, the board is not considered controlled impedance.
• Isola FR408HR or material with equivalent Dk.
• Board Surface treatment should be ENIG, althogh immersion Silver is acceptable.
• White silkscreen on top and bottom surface
• Taiyo PSR-4000 or equivalent soldermask on top and bottom, no requirements for color.

Stack Up

Layer	Thickness	Notes
Top Copper	0.043 mm / 1.7 mil	Layer 1 foil, 1 oz Cu after plating
prepreg	0.200 mm / 7.9 mil	Prepreg - Isola FR408HR 2113
Layer 2	0.018 mm / 0.7 mil	Layer 2 foil, 0.5 oz Cu
Core	0.991 mm / 39 mil	Core Isola FR408HR
Layer 3	0.018 mm / 0.7 mil	Layer 3 foil, 0.5 oz Cu
prepreg	0.200 mm / 7.9 mil	Prepreg - Isola FR408HR 2113
Bottom Copper	0.043 mm / 1.7 mil	Layer 4 foil, 1 oz copper after plating
Total Stackup	1.588 mm / 62.5 mil

Array / Panel Information

• Coordinate with Contract Manufacturer (CM) for optimal size of this panel.
• If no feedback from CM, then produce single boards (no panel).

Fabrication Files

IPC-2581 File

Filename	Notes
PROJECT-NAME-ipc2581.xml	IPC-2581 board information file

Legacy PCB Files

Filename	Notes
PROJECT-NAME-Edge_Cuts.gbr	RS274X file for the dimension (outline) layer
PROJECT-NAME-F_Silkscreen.gbr	RS274X file for the top silkscreen
PROJECT-NAME-F_Mask.gbr	RS274X file for the top soldermask
PROJECT-NAME-F_Cu.gbr	RS274X file for the top copper layer
PROJECT-NAME-In1_Cu.gbr	RS274X file for the layer 2 copper
PROJECT-NAME-In2_Cu.gbr	RS274X file for the layer 3 copper
PROJECT-NAME-B_Cu.gbr	RS274X file for the bottom copper layer
PROJECT-NAME-B_Mask.gbr	RS274X file for the bottom soldermask
PROJECT-NAME-B_Silkscreen.gbr	RS274X file for the bottom silkscreen
PROJECT-NAME-NPTH.drl	Excellon file for non-plated through holes
PROJECT-NAME-PTH.drl	Excellon file for plated through holes

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Printed Circuit Board Assembly (PCBA) Information

Assembly Info

• All components are on the top side of the board.
• This PCBA is mostly surface mount (SMT) with a few (THT) components.

Assembly Requirements

• Assemble to IPC Class 2 or better
• Bake components that are not moisture sealed to appropriate levels as required.
• Solder paste MUST be leaded.
• Aqueous flux and wash strongly preferred.
  • Clean to NASA Standard "Visibly Clean (VC)": No particles or residues are visible to the naked eye.
• No conformal coating.
• Ship in antistatic protective bag

Component Specific Assembly Information

• SMPM connectors (J3, J4) should be hand-added (there is no solder paste for their footprints).
• U1 and U28 are extremely expensive ($75 and $150 ea, respectively).
• U15 and U21 are EOL and will be supplied in cut tape form.

Assembly Files

IPC-2581 File

Filename	Notes
PROJECT-NAME-ipc2581.xml	IPC-2581 board information file

Bill of Materials (BOM)

Filename	Description
PROJECT-NAME-bom.csv	BOM in Comma Separated Variable format

Solder Paste Stencils

Filename	Notes
PROJECT-NAME-B_Paste.gbr	RS274X file for top/front solder paste stencil
PROJECT-NAME-F_Paste.gbr	RS274X file for bottom/back solder paste stencil

Mounting/Placement Location

Filename	Description
PROJECT-NAME-3u.pos	Pick and place locations for components