2 layers55 × 45.1 mm
6 layers188 × 66.8 mm
U2CEM
oxidecomputer/hw-k2This design provides a PCIe extender that converts from a U.2 PCIe device connector and provides a x4 PCIe CEM slot.
- Size
- 188 × 66.8 mm
- Copper layers
- 6
- Thickness
- 1.56 mm
- Parts
- 24
- Nets
- 62
- Pads
- 170
- Tracks, vias
- 550, 177
- Pours
- 11
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 22 Aug 2022
- Updated
- 14 Apr 2026
Overview
U2CEM is an open-source printed circuit board by oxidecomputer, from the oxidecomputer/hw-k2 repository on GitHub, published under the MPL-2.0 licence. It is a 6-layer board of 188 × 66.8 mm with 24 parts on 62 nets, routed with 550 tracks and 177 vias.
It is built around the LTST-C193KSKT-5A, RC0603JR-070RL and PCIE-064-02-F-D-EMS2-BG, with the PSAS4M2130021TR among its other parts. Its parts include 11 resistors, 2 diodes and 2 connectors.
Main components
4
LTST-C193KSKT-5A
0603-55℃~+85℃ 130° 26.05mcd 2V 587nm~594.5nm 591nm 5mA 75mW Discrete Diode Water Clear Yellow 0603 LED Indication - Discrete ROHSLite-OnLED Indication - Discrete
RC0603JR-070RL
UncategorisedUnknown makerPCIE-064-02-F-D-EMS2-BG
P=1mm-55℃~+125℃ 11.05mm 1mm 215V 64P Clamping plate Gold Phosphor bronze P=1mm PCI / PCIe Connector ROHSSamtecEdgeboard Connectors
PSAS4M2130021TR
SMD0℃~+55℃ 1.5A Brass SMD Board-to-Board and Backplane Connector ROHSAmphenolBoard-To-Board And Backplane Connector
README
README.mdhw-k2
This design provides a PCIe extender that converts from a U.2 PCIe device connector and provides a x4 PCIe CEM slot.
This is designed to work on our gimlet computer sled with a sharkfin PCIe riser. Whether this can be generally used in other applications is unknown.
This repository includes a 3d-printable encolosure design that fits in our sled and provides brackets for both of the commonly used NICs.
Status
The CAD represents a functional design.
PLM
For the sake of clarity and consistency, the PLM-released files are renamed and
organized in the plm directory.
| PLM Name | Repo Name |
|---|---|
| 913-0000114_rev1_v1.d356 | gerbers/u2CEM.d356 |
| 913-0000114_rev1_v1_bom.xlsx | pulled out of the gerber zip |
| 913-0000114_rev1_v1_gerbers.zip | gerbers/913-0000114_rev1.zip |
| 913-0000114_rev1_v1_odb.zip | gerbers/u2CEM-odb.zip |
| 913-0000114_rev1_v1_schematic.pdf | 913-0000114.pdf |
| 913-0000114_rev1_v1_stackup.xlsx | stackup-K2-6lyr-FR408HR_rev4_26_MAR_2026.xlsx |
Parts
24| Qty | Value | Footprint | References |
|---|---|---|---|
| 8 | DNI | Resistor_SMD:R_0603_1608Metric | R1, R2, R3, R4, R6, R7, R10, R11 |
| 2 | LED | LED_SMD:LED_0603_1608Metric | D1, D2 |
| 1 | 0R | Resistor_SMD:R_0603_1608Metric | R5 |
| 1 | 1.4k | Resistor_SMD:R_0603_1608Metric | R9 |
| 1 | 5.11k | Resistor_SMD:R_0603_1608Metric | R8 |
| 1 | LOGO | LOGO | G*** |
| 1 | PCIE-064-02-F-D-EMS2-BG | U2:SAMTEC_PCIE-064-02-X-D-EMS2-BG | J1 |
| 1 | PSAS4M2130021TR | U2:PSAS4M2130021TR | J2 |
The 16 most common of 24 parts.
Questions
How big is the U2CEM PCB?
It measures 188 × 66.8 mm and has 6 copper layers, 1.56 mm thick.
What parts does the U2CEM use?
24 parts, built around the LTST-C193KSKT-5A, RC0603JR-070RL, PCIE-064-02-F-D-EMS2-BG and PSAS4M2130021TR. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the U2CEM KiCad files?
From the oxidecomputer/hw-k2 repository on GitHub, at the commit this page was made from: the board is u2CEM.kicad_pcb and its schematic u2CEM.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the U2CEM design in my own project?
Its repository publishes it under the MPL-2.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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