Vishay has extended its Sfernice thick film power resistor line with the D2TO35S, an automotive-grade device packaged in the surface-mount TO-263 outline — the industry-standard D²PAK — and configured for top-side cooling.

The part is a thick film power resistor, a technology Vishay produces under the Sfernice brand it acquired in the 1980s and has since built into one of the broader commercial thick film portfolios in the passives market. The D2TO35S designation places it in Vishay's D2TO series of TO-housed power resistors, now adapted from conventional through-hole and standard surface-mount formats to a top-side cooled variant.

Top-side cooling changes the thermal architecture of the part. In a conventional surface-mount power device, heat flows from the die through the package base and the solder joints into the printed circuit board, where it spreads through copper planes. That path taxes the PCB thermally and limits how much power a board-level design can dissipate reliably.

By moving the primary heat extraction path to the top surface of the package, the D2TO35S lets designers couple the resistor directly to a heatsink or cold plate rather than pushing thermal energy into the board. Vishay says the approach improves thermal performance for automotive applications, the target market for the device. The benefit for vehicle electronics designers is straightforward: the resistor can handle its dissipation without degrading nearby board components or forcing additional copper weight into the PCB.

The choice of the D²PAK — the TO-263 outline — matters commercially. It is among the most widely used power package footprints in automotive electronics, familiar to every ECM, inverter, and DC-DC converter design team. Packaging a top-side cooled resistor in that outline means engineers can adopt the improved thermal path without abandoning existing layout libraries, pick-and-place tooling, or reflow profiles tuned to the format.

The automotive qualification signal is equally deliberate. Vehicle power stages — traction inverters, onboard chargers, battery management pre-charge and discharge circuits, and domain-zone controllers — all need resistors that can dissipate meaningful power in thermally constrained enclosures. As OEMs push 800 V architectures and denser power electronics, passives that remove heat without loading the board have moved from a convenience to a design requirement.

Vishay positions the device as part of its automotive-grade portfolio, the tier of its catalog built to meet the qualification expectations vehicle makers and their Tier 1 suppliers place on components destined for powertrain, chassis, and body electronics. The company has not yet published full electrical specifications, power ratings, or resistance ranges for the D2TO35S in the announcement; those details will land in the datasheet as the part moves through release.

For buyers and component engineers, the launch signals continued fragmentation in the power resistor market along thermal-management lines. Top-side cooled packages, already established for MOSFETs and power modules in automotive power stages, are now migrating into passive components — a shift that lets resistor suppliers compete on system-level thermal design rather than raw ohmic specifications alone.

Vishay says the D2TO35S improves thermal performance for automotive applications, and availability of full datasheet parameters will determine how quickly design teams adopt the package in current vehicle-electronics platforms.