6 open source boards using the LM331
Real designs built with the LM331, 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.
NXPPrecharge
michaelruppe
133 × 98 mm110 parts2LMIT56
NXPPrecharge
LSUTigerRacing
133 × 98 mm113 parts2LNo license7
Asm2364
Stanlazy
22 × 43.5 mm106 parts4LGPL-3.07
NXPFault Latch 2
85.8 × 94.2 mm103 parts2LNo license7
Josh Ox Ribbon Synth VCF/VCA/BBD board
JordanAceto
132.1 × 213.4 mm349 parts2LCC-BY-4.01
BPSD-2025
68.5 × 43 mm50 parts2LNo license7
The LM331 in open source designs
The gallery holds 6 open source boards using the LM331 from 4 GitHub repositories; a typical one measures about 108.9 × 96.1 mm and carries around 108 components.
83% are two-layer designs, the rest use four layers or more, and 50% carry an open source license.
The most starred is Precharge by michaelruppe.
Parts used alongside the LM331
Microcontrollers on boards using the LM331
What boards using the LM331 are built for
LM331: common questions
Where can I find a LM331 reference design?
Each of the 6 boards on this page is a real design using the LM331. 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 LM331?
The 4N35, LM1117-5.0, LM2904, LM393 and SPAN02A-12 appear in the most repositories here.
Which microcontrollers do boards using the LM331 use?
Most are built on NXP (3).
How big is a typical board using the LM331?
The median is 108.9 × 96.1 mm, and 83% are two-layer designs.
What is the most popular open source board using the LM331?
By GitHub stars, Precharge by michaelruppe, with 56 stars.
Can I simulate one of these boards using the LM331 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.