What onsemi actually announced
The EPP is not a new chip. It is a new way of packaging chips — and the distinction matters more than the headline numbers.
In a conventional traction inverter, silicon-carbide dies are soldered into a module, the module is bolted to a housing, and a separate gate-driver board handles control. Onsemi turns that inside out: the silicon wafer itself becomes the foundation of the package, and FETs, gate drivers and controllers are integrated into a single unit on top of it. The same architecture can carry silicon, SiC or gallium nitride (GaN).
Onsemi claims up to four times higher power density and up to 15% lower power losses in traction inverters against conventional designs. For the platform as a whole — industrial drives and AI data-centre power supplies included — the company quotes a three-to-five-fold density gain and development cycles as short as four months. Subaru, the first announced automotive partner, receives early access to engineering samples, simulation models and technical support, but has made no production decision. First samples go to selected customers later this year.
The die is the package — and that is where the volume goes
Onsemi's own framing is that electrical, thermal and mechanical properties get optimised inside one architecture instead of being solved separately and then bolted together. The concrete consequence is lower parasitic inductance, because the current loops between die, driver and DC link get shorter. Lower inductance means less voltage overshoot when switching, which in turn allows higher switching frequencies — and higher switching frequencies shrink the bulky, expensive parts around the silicon: the DC-link capacitor, the EMI filter, the busbars and their copper, the cooling plate.
That is a genuine system-level gain, and it is the same logic that has driven R&D spending across the industry. We covered how Panasonic is compressing its own development timelines at its new Osaka R&D hub — the race is not only about better materials, but about fewer process steps between the idea and the validated part.
Onsemi also says EPP can be built on existing 12-inch silicon wafer lines, so key integration steps happen inside semiconductor production rather than in a specialised power-module assembly line. If that holds, it should show up as lower cost per kW and less qualification work per power class. Note what is missing: no metric is specified for the "four times" figure — kW per litre and kW per kilogram are very different claims, and neither is defined at a given operating point or junction temperature. Nor are any figures given for real-world driving conditions. That is a claim to be re-measured, not believed.
15% lower losses: 0.06 kWh per 100 km, or about €2.90 a year
Here is the arithmetic a buyer should care about. Take a mid-size electric crossover using 17 kWh/100 km measured at the battery, with inverter losses at a realistic 2.5% of the traction energy. That is 0.425 kWh/100 km burned in the silicon.
Cut those losses by 15%, as Onsemi promises, and you keep 0.064 kWh per 100 km. At €0.30/kWh of home charging that is €0.02 per 100 km — €2.90 over 15,000 km a year. Charge exclusively on public DC at €0.60/kWh and you save under €6. In range terms, on a car with 400 km of real-world range, the gain is about 1.5 km per charge.
Context makes the scale obvious. The difference between a resistive heater and a heat pump costs roughly 1 to 1.5 kWh/100 km in winter — more than twenty times the inverter saving. Your driving style, tyre choice and cabin temperature will move consumption by an order of magnitude more than this. The 15% figure is real engineering, but it is not a range story. It is a bill-of-materials story: less copper, smaller capacitors, smaller cooling hardware, one package instead of five, and a cheaper e-axle for the manufacturer.
Competition: Infineon, ST, Wolfspeed — and the Chinese fabs
Onsemi is not alone in attacking the packaging layer. Infineon has built its SiC business around module integration and improved die-attach and interconnect technologies; STMicroelectronics and Wolfspeed are pushing vertically integrated SiC from substrate to module; BYD Semiconductor and a growing group of Chinese suppliers are doing the same behind a domestic supply chain.
Onsemi's differentiation is that the integration happens at wafer level rather than at module level — closer to standard semiconductor manufacturing. The commercial proof sits elsewhere in its order book: the company has spent the past three years signing long-term SiC supply deals with tier-one suppliers, including a ten-year agreement with Vitesco (now part of Schaeffler) and a separate deal with Magna. Packaging efficiency is how those contracts stay profitable.
The Czech connection
Europe has a stake here. Onsemi's main European manufacturing footprint is in Rožnov pod Radhoštěm in the Czech Republic, where the company announced a multi-year investment programme in 2024 to expand silicon-carbide capacity. If a wafer-level packaging architecture spreads across the company's portfolio, it lands in existing 12-inch lines rather than in new, dedicated plants — one reason Onsemi is pitching EPP as a cost play as much as a technology play.
Where power electronics are designed and built is also becoming a commercial question in its own right. As ACEA has warned, EU-built EVs face a 10% UK tariff from 2027 unless the battery origin rules are delayed — the same logic of local content will eventually reach deeper into the drivetrain.
What should a buyer do with this?
Nothing, if you are ordering a car this year. Traction inverters already run at 95–98% efficiency; the cars on sale today are not waiting for this. If you own an EV, the useful number is not 15% — it is what you actually pay per kWh. Our charging cost calculator and range calculator put your own consumption and tariff into the equation, and they will tell you far more about your annual bill than any packaging announcement.
For scale, remember what efficiency work buys versus what infrastructure costs: EZO is raising €150 million for 3,000 UK and Ireland charge points, which works out at €50,000 per point. A driver saves €2.90 a year from better silicon. That is not an argument against the silicon — it is an argument about where the kilometres are actually won.
What happens next: engineering samples later this year, a Subaru evaluation without a decision, and platform-level numbers that still have to survive automotive series validation. When they do, the first thing you will notice is not range. It will be the price list.
Source: https://www.electrive.com/2026/09/18/onsemi-aims-to-quadruple-power-density-of-ev-inverters/
