2 layers87.6 × 73 mm
Stemcell panel
megamind4089/STeMCell
STM32F4 breakout board in pro micro pinout. Designed mainly for ergo split keyboards.
258 parts123
2 layers17.8 × 31.9 mm
Stemcell
megamind4089/STeMCell123STM32F4 breakout board in pro micro pinout. Designed mainly for ergo split keyboards.
- Size
- 17.8 × 31.9 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 37
- Nets
- 56
- Pads
- 269
- Tracks, vias
- 390, 58
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 6 (file 20211014)
- Created
- 16 Jan 2022
- Updated
- 6 Sep 2022
Overview
Stemcell is an open-source printed circuit board by megamind4089, from the megamind4089/STeMCell repository on GitHub. It is a 2-layer board of 17.8 × 31.9 mm with 37 parts on 56 nets, routed with 390 tracks and 58 vias.
It is built around the XC6220B331MR and B5819W. Its parts include 12 capacitors, 8 resistors, 4 connectors, 2 ICs and 2 diodes. It belongs with the keyboards and input boards and the STM32 and AVR (ATmega, ATtiny) boards of this library.
Main components
2
XC6220B331MR
SOT-23-5-40℃~+85℃@(Ta) 1 25uA 3.3V 400mV@(800mA) 5.5V 50dB@(10kHz) 900mA Fixed Over Current Protection、Over Temperature Protection Positive SOT-23-5 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSTECH PUBLICVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
B5819W
SOD-123-55℃~+125℃ 1.5A 1mA@40V 25A 40V 600mV@1A Standalone SOD-123 Schottky Diodes ROHSMDDSchottky Diodes
README
README.mdSTeMCell
STM32 breakout in promicro footprint
Features:
- Pro micro footprint
- STM32F4x1 series MCU
- Two layer PCB
- Support half duplex USART communication in any of D0, D1, D2, D3 using jumpers
- Onboard switch to enable/disable USB DFU bootloader
- Inbuilt TX pullup for UART half duplex communication
- User LED on PA8
- Extra 5 pinout on bottom like Elite C
- Supports QMK and ZMK
- JLCPCB assembly supported
v2.1.0
Parts
37| Qty | Value | Footprint | References |
|---|---|---|---|
| 6 | 100n | Capacitor_SMD:C_0402_1005Metric | C4, C5, C6, C7, C8, C12 |
| 3 | 10k | Resistor_SMD:R_0402_1005Metric | R6, R7, R8 |
| 3 | 4.7u | Capacitor_SMD:C_0402_1005Metric | C2, C3, C9 |
| 2 | 20p | Capacitor_SMD:C_0402_1005Metric | C10, C11 |
| 2 | 5k1 | Resistor_SMD:R_0402_1005Metric | R2, R3 |
| 1 | 10u | Capacitor_SMD:C_0402_1005Metric | C1 |
| 1 | 1A Fuse | Fuse:Fuse_0805_2012Metric | F1 |
| 1 | 220 | Resistor_SMD:R_0402_1005Metric | R1 |
| 1 | 2k2 | Resistor_SMD:R_0402_1005Metric | R4 |
| 1 | 4.7k | Resistor_SMD:R_0402_1005Metric | R5 |
| 1 | B5819W | Diode_SMD:D_SOD-123 | D2 |
| 1 | Boot0 | Button_Switch_SMD:SW_SPST_CK_KXT3 | SW1 |
| 1 | Down | stemcell:Pins5_castellated | J4 |
| 1 | G*** | kibuzzard-620B7294 | kibuzzard-620B7294 |
| 1 | HSE1 8Mhz 12pF | Crystal:Crystal_SMD_3225-4Pin_3.2x2.5mm | Y1 |
| 1 | LED | LED_SMD:LED_0402_1005Metric | D1 |
| 1 | Left | stemcell:Pins12_castellated | J2 |
| 1 | RX0 | stemcell:SOLDER_JUMPER_3 | JP2 |
| 1 | Right | stemcell:Pins12_castellated | J3 |
| 1 | SCL | stemcell:SOLDER_JUMPER_3 | JP4 |
| 1 | SDA | stemcell:SOLDER_JUMPER_3 | JP3 |
| 1 | STM32F4x1CxUx | Package_DFN_QFN:QFN-48-1EP_7x7mm_P0.5mm_EP5.6x5.6mm | U1 |
| 1 | TX PUp | stemcell:SOLDER_JUMPER_3 | JP5 |
| 1 | TX0 | stemcell:SOLDER_JUMPER_3 | JP1 |
| 1 | USB C Connector | stemcell:USB-C-C168688 | J1 |
| 1 | XC6220B331MR | Package_TO_SOT_SMD:SOT-23-5 | U2 |
Questions
How big is the Stemcell PCB?
It measures 17.8 × 31.9 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Stemcell use?
37 parts, built around the XC6220B331MR and B5819W. 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 Stemcell KiCad files?
From the megamind4089/STeMCell repository on GitHub, at the commit this page was made from: the board is stemcell.kicad_pcb and its schematic stemcell.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Stemcell design in my own project?
Its repository states no licence, so its author keeps all rights: ask megamind4089 before reusing the design.
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