14 open source boards using the 3.3V
Real designs built with the 3.3V, from public GitHub projects: a quick way to see how others power, decouple and connect it. Each board comes with its KiCad files, full parts list and a render — and you can simulate its firmware on HardLabs.
- schematic only · 69 partsAVR/Arduino
Thotcon0x5
Workshop88
69 partsNo license7 
Slimarm hypericum
jlywxy
50 × 33.5 mm126 parts4LGPL-2.00
Nordic nRFSeeed Studio XIAO nRF52840 v1.3
sinismylastname
21 × 17.8 mm79 parts2LNo license1
Nordic nRFSeeed Studio XIAO nRF52840 v1.3
feastorg
21 × 17.8 mm79 parts2LCC0-1.01
Slarm zero awa20.1
49.9 × 40.7 mm124 parts4LGPL-2.00
Nordic nRFSeeed Studio XIAO nRF52840 v1.3
AM1NOM
21 × 17.8 mm79 parts2LMIT0
Nordic nRFSeeed Studio XIAO nRF52840 v1.3
jadenvv
21 × 17.8 mm79 parts2LNo license1
RP2040/RP2350Output controller
mekatrol
238 × 122 mm161 parts2LNo license0
Us3c
64.6 × 39.2 mm90 parts4LGPL-2.00
RP2040/RP2350Controller
140 × 100 mm146 parts2LNo license0
Slimarm classic 2410
49.3 × 40.8 mm86 parts4LGPL-2.00
Slimarm carambola
50 × 39.9 mm84 parts4LGPL-2.00
Slimarm almond b
50 × 23.9 mm70 parts4LGPL-2.00
Slimarm classic 2416
14.6 × 16.6 mm3 parts2LGPL-2.00
The 3.3V in open source designs
The gallery holds 14 open source boards using the 3.3V from 7 GitHub repositories; a typical one measures about 49.9 × 33.5 mm and carries around 82 components.
54% are two-layer designs, the rest use four layers or more, and 64% carry an open source license.
The most starred is Thotcon0x5 by Workshop88.
Parts used alongside the 3.3V
Microcontrollers on boards using the 3.3V
What boards using the 3.3V are built for
3.3V: common questions
Where can I find a 3.3V reference design?
Each of the 14 boards on this page is a real design using the 3.3V. Open one to see how it is wired up, with the full BOM, a render of the layout and links to its KiCad files.
What parts are used alongside the 3.3V?
The BQ25100, LSM6DS3TR-C, 5V and W25Q128JVS appear in the most repositories here.
Which microcontrollers do boards using the 3.3V use?
Most are built on Nordic nRF (4), RP2040/RP2350 (2) and AVR/Arduino (1).
How big is a typical board using the 3.3V?
The median is 49.9 × 33.5 mm, and 54% are two-layer designs.
What is the most popular open source board using the 3.3V?
By GitHub stars, Thotcon0x5 by Workshop88, with 7 stars.
Can I simulate one of these boards using the 3.3V before building it?
Yes. HardLabs turns a board's netlist and BOM into a working simulation, so you can boot and test firmware against it with no hardware on your desk.