PCB板电流载流能力介绍

Current lead capacity of PCB traces

European Power-Semiconductor andElectronics Company

When mounting IGBT modules like EconoPACK or EconoPIM on a Printed Circuit Board,the PCB has to lead the current. In this case, the copper trace in the PCB works like a re-sistor and turns hot depending on the current; an unpleasant effect. If the PCB tempera-ture goes up to approx. 120C° with standard epoxy material, a glaze effect in the core ofthe PCB starts which will destroy the PCB. Due to the different thermal expansion coeffi-cient of copper and epoxy, the PCB quickly gets old with strong power cycling.Helpful solutions are:• If possible, use the surface traces for power transfer.• Use as much copper area as possible.• Provide for air cooling of the PCB.

• Do not use heat traps within your layout.Experience value for PCB design:Copper 70/105um thick

Two Layer PCB 1,4A/mm 70µmSurface traces 1,6A/mm 105µm

Creepage distance UL508c at 1000VDC =5,08mm

PCB Core Creepage distance to ground potential =12mm

Surface Copper traces 35µm for signal *Four layer PCB 0,7A/mm 70/105um Inside traces

Creepage distance UL508c at 1000VDC =0,4mmPCB Core*Please check the a.m. values with the PCB manufacturers.

For further information write to:eupec

Marketing SM PD Tel: +49-2902-7-1159Max-Planck-Str. 5 Fax: +49-2902-7-1150D-59581 Warstein Internet:: http://www.eupec.com2000-05-24