Workshop - Clearances and Track width references
The minimum track that can be made in the Department is 0.3mm (12mil) wide. Please visit the Printed Circuit Board Design Guide page for more information on manufacturing pcbs here in the Department.
The following tables are to provide you with some information on regarding trackwidth and electrical clearances when doing your pcb design.
There are industry standards for almost every aspect of PC board design. These standards are controlled by the former Institute for Interconnecting and Packaging Electronic Circuits, who are now known simply as the IPC ( www.ipc.org ). There is a IPC standard for every aspect of PC board design, manufacture, testing and anything else that you could ever need. The major document that covers PC board design is IPC-2221, "Generic Standard on Printed Board Design". This standard superseded the old IPC-D-275 standard (also Military Std 275) which has been used for last half century. Local countries also have their own various standards for many aspects of PC board design and manufacture but by large, the IPC standards are the accepted industry standard around the world.
The calculations to figure out a required track width based on the current and the maximum temperature rise are a little complex. They can also be quite inaccurate, as the standard is based on a set of non-linear graphs based on measured data from around half a century ago. These are still reproduced in the IPC standard.
A handy track width calculator program can be found at www.ultracad.com/calc.htm and gives results based on the IPC graphs.
(Above information courtsey by Silicon Chip Magazine - Australia ).
Here is a useful tool for calculating pcb track width http://www.pcbco.com.au/tracecalc.html
The conversion table is courtsey from Silicon Chip Magazine - Australia:
The conversion table is courtsey from Silicon Chip Magazine - Australia:
The conversion table below might be useful to you when working on your pcb design:
The diagram below gives you an example for track clearances.
Listed below are typical examples of component leg and pin sizes and the drill that can be used for these components.
| Component | Lead (mm) | Drill (mm) |
|---|---|---|
| 0.25W Resistors | 0.6mm | 0.8mm |
| 0.5W Resistors | 0.7 | 0.8 |
| 1.0W Resistors | 0.8 | 1.0 |
| Wire Wound Resistors | 0.8 - 0.9 | 1.0 -1.1 |
| Ceramic Capacitors | 0.6 | 0.8 |
| Tag Tantalum capacitors | 0.5 | 0.8 |
| Electrolytic capacitors (small) | 0.5 | 0.8 |
| Electrolytic capacitors (large) | 0.5 | 0.8 |
| Small signal diodes | 0.56 | 0.8 |
| Power diodes (small) | 0.9 | 1.0 -1.1 |
| Power diodes (large) | 1.3 | 1.5 |
| Small signal diodes | 0.56 | 0.8 |
| SCRs (TO-220 & TO-126 package) | 1.4 | 1.5 |
| Transistor (power plastic) | 0.89 -0.9 | 1.1 |
| Intergrated circuits (std. DIL) | 0.56 | 0.8 |
| Trimpots (small) | 0.9 | 1.0 - 1.1 |
| Trimpots (large) | 1.1 | 1.1 - 1.2 |
| PC Board pins (small) | 1.0 | 1.1 |
| PC Boards pins (large) | 1.6 | 1.65 |
| Molex pins | 0.75 | 0.8 - 1.0 |
| LEDs (small) | 0.6 | 0.8 |
| LEDs (large) | 0.8 | 1.0 |
| Metalised capacitors (small) | 0.55 | 0.8 |
| Metalised capacitors (large) | 0.91 | 1.0 - 1.1 |
| PC Board relays | 1.0 | 1.1 - 1.3 |
| Multi-strand hook-up wire (7/0.2) | 0.65 | 0.8 |
| Multi-strand hook-up wire (10/0.2) | 0.9 | 1.1 - 1.3 |
| Multi-strand hook-up wire (24/0.2) | 1.25 | 1.3 - 1.4 |