Small top-side cooled automotive mosfets keep heat out of the PCB

Infineon is aiming at automotive power control with a 5 x 7mm top-side cooled surface-mount package, pitching it against the 5 x 6mm bottom-cooled SSO8.

The package, SSO10T, has a 10μm gap instead of a thermal pad on the PCB side, and around 95% of heat will leave through the top, according to the company, typically to the ECU housing or a cold-plate.

It is expected to be used with a thermal interface pad to accommodate tolerance between PCB and heatsink surface.

SSO10T dissipating 5W in 85°C ambient with various thermal interface thickness and material

“SSO10T is based on the industry standard SSO8,” it said. “However, due to its top-side cooling, the SSO10 offers more than 20% and up to 50% higher performance than the standard SSO8 – depending on the thermal interface material used and the its thickness.”

As a thermal patch and thermal vias are no longer required on the PCB, the company predicts that some designs will be able to use simple double-sided PCBs.

So far, the company has released four mosfets in the package, all 40V n-channel:

IAUCN04S6N007T 0.75mΩ 120A (390A) 100nC Qg
IAUCN04S6N009T 0.90mΩ 120A (330A) 85nC Qg
IAUCN04S6N013T 1.32mΩ 120A (230A) 52nC Qg
IAUCN04S6N017T 1.73mΩ 120A (200A) 37nC Qg

All these figures are at 25°C. 120A is a nominal limit that is affected by external thermal design, while the die limit is in brackets. Higher pulses can be handled: for example …N007T can handle 1.3kA for 100μs.

Internal construction is soldered copper-clip, seen in this underside view.