2 layers34 × 18 mm Hotswap, the printed circuit board in 3D

Hotswap

A kicad project for an monolithic power systems MP5056 board

Size: 34 × 18 mm
Copper layers: 2
Thickness: 1.6 mm
Parts: 21
Nets: 13
Pads: 60
Tracks, vias: 41, 15
Pours: 3
Routed: Yes
KiCad: KiCad 10.0 (file 20260206)
Created: 11 Aug 2026
Updated: 11 Aug 2026

Overview

Hotswap is an open-source printed circuit board by jrowny, from the jrowny/mp5056 repository on GitHub. It is a 2-layer board of 34 × 18 mm with 21 parts on 13 nets, routed with 41 tracks and 15 vias.

It is built around the MP5056GQV-Z and SMAJ22A. Its parts include 6 resistors, 5 capacitors, 2 diodes and 1 IC. It belongs with the keyboards and input boards of this library.

Main components

README

README.md

Monolithic Power Systems MP5056 Board

MP5056 board render

This is a kicad project/pcb design for a monolithic power systems MP5056. The purpose is to protect against shorts/overcurrent with exposed magnetic connectors like these ones (affiliate link).

Video

I made a video about using this with a DeWalt battery here.

NextPCB

Thanks to NextPCB for sponsoring this project. Get your first PCB order at $0.1 via NextPCB.

Important: I am a hobbyist electronics engineer, please evaluate this design before using it.

Component Values

Values chosen per the MP5056 datasheet:

Component	Value	Notes
EN divider	100 kΩ / 22 kΩ	Identical to FB, ~3.2 V at 18 V input
ISET	30 kΩ	Sets current limit to ~4 A at 18 V input
AUTO	floating
FLTB	floating
PG	floating
FB divider	100 kΩ / 22 kΩ	~3.2 V at 18 V input
SS (soft start)	100 nF
TIMER	220 nF
IMON	10 kΩ to ground	Not used

Parts

Qty	Value	Footprint	References
2	100k	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R1, R5
2	100nF	Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder	C1, C4
2	22k	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R2, R6
2	SMAJ22A	Diode_SMD:D_SMA	D1, D2
1	10k	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R4
1	10µF	Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder	C5
1	220nF	Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder	C2
1	30k	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R3
1	4.7µF	Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder	C3
1	AUTO	TestPoint:TestPoint_Pad_1.5x1.5mm	AUTO
1	FLTB	TestPoint:TestPoint_Pad_1.5x1.5mm	FLTB
1	IN +	Connector_Wire:SolderWire-1sqmm_1x01_D1.4mm_OD3.9mm	IN+
1	IN -	Connector_Wire:SolderWire-1sqmm_1x01_D1.4mm_OD3.9mm	OUT-
1	MP5056GQV-Z	jlc-proj:MP5056GQV-Z	U1
1	OUT +	Connector_Wire:SolderWire-1sqmm_1x01_D1.4mm_OD3.9mm	OUT+
1	OUT -	Connector_Wire:SolderWire-1sqmm_1x01_D1.4mm_OD3.9mm	IN-
1	PG	TestPoint:TestPoint_Pad_1.5x1.5mm	PG

Questions

How big is the Hotswap PCB?

It measures 34 × 18 mm and has 2 copper layers, 1.6 mm thick.

What parts does the Hotswap use?

21 parts, built around the MP5056GQV-Z and SMAJ22A. 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 Hotswap KiCad files?

From the jrowny/mp5056 repository on GitHub, at the commit this page was made from: the board is hotswap.kicad_pcb and its schematic hotswap.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the Hotswap design in my own project?

Its repository states no licence, so its author keeps all rights: ask jrowny before reusing the design.

Category and platform

Keyboards and input

Project files

Show this board on your page

A live frame, for any web page

<iframe src="https://pcbkit.io/embed/boards/jrowny-mp5056" title="Hotswap in PCBKit" width="100%" height="480" style="border:0;border-radius:12px" allow="fullscreen" loading="lazy"></iframe>

A picture

<img src="https://pcbkit.io/embed/boards/jrowny-mp5056.jpg" alt="Hotswap" width="1200" height="900">

A picture that opens the board, for a README

[![Hotswap](https://pcbkit.io/embed/boards/jrowny-mp5056.jpg?size=s)](https://pcbkit.io/boards/jrowny-mp5056)

Source

Repository: jrowny/mp5056
Board file: hotswap.kicad_pcb
Commit: 353b322
Licence: Not stated

Similar boards

4 layers96 × 100 mm
OtterCastAmp
Ottercast/OtterCastAmp
OtterCastAmp is an open-source WiFi Speaker amplifier, based on a Sochip S3 SoC. Powered by any USB PD adapter for up to 100W of music.
272 parts341MIT
4 layers54.7 × 75.8 mm
Esphome dot
gcormier/esphome-dot
Beginnings of a replacement PCB for Amazon Echo Dot v5.
62 parts16
4 layers50 × 18 mm
T41-USB C PSU
TobleMiner/T41-USB-C-PSU

71 parts5
4 layers84 × 81 mm
Blinkekatze charger
TobleMiner/blinkekatze-charger
A USB-C powered 20 port 5V 1.5A USB-C charger
416 parts2
4 layers60 × 60 mm
AUXSPACE core pcb
AUXSPACEeV/AUX-Core
Core/Master PCB for the Auxspace Avionics stack
83 partsCERN-OHL-P-2.0
2 layers66.3 × 71.8 mm
New pcb
Colorado-School-of-Mines-Robotics-Club/VEX-Override
VURC team ORDGR's code for the 26-27 VEX Override game
44 parts
2 layers120 × 60 mm
ControlBoard
itsmeibii/SplitFlap-Control-Board
Raspberry Pi 4 control board for a split-flap display + HUB75 LED panels: USB-C PD input, 8A buck, Pi eFuse. KiCad, gerbers, BOM, enclosure.
62 parts
6 layers90.2 × 95.9 mm
EPS mppt board
JaronCyna/sat_mppt_pcb
Maximum Power Point Tracking board meant for use in the QSET 3U CubeSat
287 parts