Mounting DE-Series MOSFETs - a comparison of two recognised techniques

MOSFET devices have developed significantly to become the number one choice for high-power applications in power electronics and electronic communication. Commercially available devices now operate into the VHF range, boasting output powers of up to 300 W. The IXYS RF manufactured IXZ210N50L RF power MOSFET falls into this category of MOSFET devices. It is optimised for linear operation and suitable for broadcast and communication applications. This paper presents two proposed techniques, from the manufactures, for mounting this device with regard to high-power applications. These two techniques (A and B) are contrasted with regard to thermal efficiency, cost and simplicity. The MOSFET drain current is adjusted from 0.5 to 4.5A in both techniques with corresponding heat sink temperatures being measured using the PICO TC-08 temperature logger. The results revealed that technique B has a slightly lower on-state resistance when compared to technique A. However, technique B has a more complex mount and a higher cost. The change in on-state resistance is due to a rise in the junction temperature resulting from the drain current increase.