Vishay Siliconix MOSFETs With Double-Sided Cooling Offer 1.9 Milliohms On-Resistance
Vishay Intertechnology Inc. is shipping the first two power MOSFETs to be offered in its innovative PolarPAK package, which uses double-sided cooling to reduce thermal resistance, package resistance, and package inductance for a more efficient, faster-switching power MOSFET.
PolarPAK was specifically designed for easy handling and mounting onto the PCB with high-speed assembly equipment, thus enabling high assembly yields in mass-volume production. This is one reason why PolarPAK has already earned the distinction of being the first MOSFET package with double-sided cooling to be sourced by multiple manufacturers, beginning with a license agreement concluded between Vishay and STMicroelectronics in March 2005.
Typical applications for the new PolarPAK devices are expected to include voltage regulator modules in notebook and desktop PCs, and other systems requiring high-efficiency dc-to-dc conversion. By delivering superior thermal performance and reducing package-related losses, the 5-mm by 6-mm PolarPAK package allows designers to create smaller, more compact circuit designs with a lower component count. With a height dimension of just 0.8 mm, half the height of the SO-8, the PolarPAK package enables end products that are thinner as well.
The first PolarPAK power MOSFETs are the 30-V n-channel SiE802DF and SiE800DF. Optimized for the low-side control switch in synchronous rectification dc-to-dc converters, the SiE802DF offers exceptionally low on-resistance of 1.9 milliohms maximum at a 10-V gate drive (2.6 milliohms maximum at 4.5 V) and can handle current levels up to 60 A.
The SiE800DF, optimized to work as the low-duty-cycle high-side MOSFET in synchronous dc-to-dc converter designs, features a very low typical gate charge Qg of 12 nC, with on-resistance of 7.2 milliohms maximum at 10 V and 11.5 milliohms at 4.5 V.
The new PolarPAK power MOSFETs, which have the same footprint dimensions of the standard SO-8, dissipate 1 degree Celsius per Watt from their top surface and 1 degree Celsius per Watt from their bottom surface. This provides a dual heat dissipation path that gives the devices twice the current density of the standard SO-8.
With its improved junction-to-ambient thermal impedance, a PolarPAK power MOSFET can either handle more power or operate with a lower junction temperature. A lower junction temperature means a lower rDS(on), which in turn means higher efficiency.
Samples and production quantities of the SiE800DF and SiE802DF are available now, with lead times of 10 to 12 weeks for larger orders. Pricing in 10,000-piece quantities starts at $1.00 per piece for the SiE802DF and $0.80 per piece for the SiE800DF.
