2 layers49 × 31 mm

LM5155-flyback

A Nixie Tube based clock. Because everyone has to play with Nixies once, right?

Size: 49 × 31 mm
Copper layers: 2
Thickness: 1.6 mm
Parts: 33
Nets: 23
Pads: 114
Tracks, vias: 102, 31
Pours: 5
Routed: Yes
KiCad: KiCad 10.0 (file 20260206)
Created: 27 May 2019
Updated: 4 Jun 2026

Overview

LM5155-flyback is an open-source printed circuit board by bartlettD, from the bartlettD/nixie-clock repository on GitHub. It is a 2-layer board of 49 × 31 mm with 33 parts on 23 nets, routed with 102 tracks and 31 vias.

It is built around the LM5156HPWP, BAS70 and PSMN014-80YLX, with the SBR1U400P1 among its other parts. Its parts include 14 resistors, 7 capacitors, 2 diodes, 1 IC and 1 transistor. It belongs with the lEDs and displays boards of this library.

Main components

README

README.md

nixie-clock

A Nixie Tube based clock. Because everyone has to play with Nixies once, right?

Introduction

The goal of this project is to design and contstruct a simple 4/6-Digit clock based around a set of IN-12B Nixie Tubes. They are a type of cold-cathode display neon readout tube invented in the 1950's and used commonly in the USSR in volume manufacture until the 1980's after the rest of the world had moved on to 7-Segment LED arrays and other indicator technologies.

Parts

Qty	Value	Footprint	References
7	TestPoint	TestPoint:TestPoint_Keystone_5019_Miniature	TP1, TP2, TP3, TP4, TP5, TP6, TP8
2	1Meg	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R13, R14
2	499k	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R3, R12
1	1	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R6
1	1.6n	Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder	C5
1	100k	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R8
1	10k	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R5
1	1u	Capacitor_SMD:C_2220_5750Metric_Pad1.97x5.40mm_HandSolder	C1
1	1uF	Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder	C3
1	2m	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R1
1	3.79k	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R7
1	33n	Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder	C4
1	4.7u	Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder	C2
1	43k	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R10
1	5.6k	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R4
1	5n	Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder	C6
1	82k	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R9
1	88.7k	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R2
1	BAS70	Package_TO_SOT_SMD:SOT-23	D2
1	C	Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder	C7
1	EP7-5801_750315825	Transformer_SMD_Wurth:T_Wurth_WE-FLYLT-EP7-5801	T1
1	LM5156H	Package_SO:Texas_HTSSOP-14-1EP_4.4x5mm_P0.65mm_EP3.4x5mm_Mask3.155x3.255mm_ThermalVias	U1
1	PSMN014-80YL	Package_TO_SOT_SMD:LFPAK56	Q1
1	R	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R11
1	SBR1U400P1	Diode_SMD:D_PowerDI-123	D1

Questions

How big is the LM5155-flyback PCB?

It measures 49 × 31 mm and has 2 copper layers, 1.6 mm thick.

What parts does the LM5155-flyback use?

33 parts, built around the LM5156HPWP, BAS70, PSMN014-80YLX and SBR1U400P1. 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 LM5155-flyback KiCad files?

From the bartlettD/nixie-clock repository on GitHub, at the commit this page was made from: the board is PCB/lm5155-flyback/LM5155-flyback.kicad_pcb and its schematic PCB/lm5155-flyback/LM5155-flyback.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the LM5155-flyback design in my own project?

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

Category and platform

LEDs and displays

Project files

Show this board on your page

A live frame, for any web page

<iframe src="https://pcbkit.io/embed/boards/bartlettd-nixie-clock" title="LM5155-flyback 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/bartlettd-nixie-clock.jpg" alt="LM5155-flyback" width="1200" height="900">

A picture that opens the board, for a README

[![LM5155-flyback](https://pcbkit.io/embed/boards/bartlettd-nixie-clock.jpg?size=s)](https://pcbkit.io/boards/bartlettd-nixie-clock)

Source

Repository: bartlettD/nixie-clock
Board file: PCB/lm5155-flyback/LM5155-flyback.kicad_pcb
Commit: 584e644
Licence: Not stated

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