Combined orders placed with Taiwan-based PCB manufacturers for the fourth quarter of 2011 are likely to slip 15% or more sequentially, according to industry sources. Demand across all PC and display applications appears to be slower than in previous years.

Demand for smartphones, the main force behind PCB makers' sales growth, also turned weak recently, the sources said.

The order slump was anticipated also in part due to fewer-than-expected orders from Apple, the sources indicated. Suppliers to Apple were informed that orders for the fourth quarter have been revised downward because of the sluggish US and Europe economies, the sources revealed.

Compeq Manufacturing, Nan Ya PCB (NPC), Tripod Technology and Unimicron Technology reportedly are among the PCB suppliers for iPhone devices. And Taiwan-based companies pinpointed by industry insiders as suppliers for iPad tablets include Compeq, Gold Circuit Electronics (GCE), NPC and Tripod.