STMicroelectronics announced its power devices to be assembled in the metal topped PolarPAK package. The STK800 and STK850 are 20A and 30A power MOSFETs needing the same 5mm x 6mm board area as a standard SO-8 package with profile of 0.8mm. ST announced a license agreement with Siliconix in March 2005 to use the PolarPAK technology. Yet compared to the standard SO-8, the PolarPAK dissipates heat so efficiently that it can handle twice the current within the same footprint.The devices are manufactured using the optimization of ST's STripFETT technology - which is based on increased cell density and smaller cell features.

Typical RDS(on) of the 20A STK800 is 6.0mOhm, and of the 30A STK850 is 2.9mOhm, at 10V. With its low capacitance and total gate charge, the STK800 is the choice as a control FET in non-isolated DC-DC step down converters, while exceptionally low RDS(on) makes the STK850 an solution as a synchronous FET. The new package provides improved die protection, and easy handling in manufacture, maintaining compatibility with existing SMD assembly equipment. Samples of the new devices are available now. The STK800 is priced at $1.20 and the STK850 at $1.60, for quantities of 1000.