IGBT Head-to-Head: Mitsubishi CM600DX-24T vs. Infineon FF600R12IP4

In a 350kW central solar inverter, an efficiency difference of just 0.5% can mean a loss of 1,750 watts—enough to power a high-performance server rack. Every hour the sun shines, that wasted energy translates directly into lost revenue and a higher levelized cost of energy (LCOE). This is the reality that drives senior power electronics engineers to scrutinize every component, but none more so than the core power switching device: the IGBT module. In the high-stakes 1200V/600A category, two titans dominate the landscape: the Mitsubishi CM600DX-24T and the Infineon FF600R12IP4. Both are industry workhorses, but they are born from different design philosophies and silicon technologies. This report puts them head-to-head, moving beyond surface-level datasheet figures to provide a definitive engineering analysis for your next high-power design.

At a Glance: The Contenders

Before diving into the nuanced technical differences, let’s establish a baseline by comparing the key top-level specifications of these two modules. While they share the same voltage and current ratings, the subtle distinctions in other parameters hint at their underlying technological disparities.

Round 1: The Battle of Silicon – CSTBT™ vs. TRENCHSTOP™

The most significant difference between these two modules lies in their core IGBT technology. Mitsubishi’s CSTBT™ (Carrier Stored Trench Gate Bipolar Transistor) technology, particularly in its 7th generation, is engineered to enhance the carrier concentration in the n-drift layer. This results in a remarkably low collector-emitter saturation voltage (VCE(sat)). As shown in the table, the CM600DX-24T boasts a typical VCE(sat) of 1.85V at 125°C, which is roughly 10% lower than the FF600R12IP4’s 2.05V. For a 350kW inverter operating at a high duty cycle, this seemingly small voltage difference translates into a significant reduction in conduction losses, directly impacting overall system efficiency and reducing the thermal load on the cooling system.

On the other hand, Infineon’s TRENCHSTOP™ IGBT4 technology is a field-stop concept renowned for its balanced performance, particularly its optimization of switching characteristics. While its VCE(sat) is slightly higher, the technology is designed for fast and clean switching, though in this specific comparison, the switching energy data points to a different conclusion. This highlights a critical lesson for engineers: never rely on brand technology generalizations alone. A deep dive into specific datasheet values is essential, which we cover in the next section.

For more foundational knowledge on these structures, our guide on Deconstructing the IGBT: A Deep Dive into Its Hybrid Structure and Technology provides a comprehensive overview.

Round 2: Power Loss Deep Dive – Conduction vs. Switching

In power electronics, the total power loss is a sum of conduction and switching losses. The choice between these modules depends heavily on the application’s operating frequency.

Winner for Low-Frequency (e.g., Industrial Motor Drives): Mitsubishi CM600DX-24T
At lower switching frequencies (e.g., < 5 kHz), conduction losses dominate the total loss equation. The CM600DX-24T’s lower VCE(sat) gives it a clear and undeniable advantage. This makes it an excellent candidate for high-current motor drives where switching speeds are often limited by the motor’s characteristics.

Winner for High-Frequency (e.g., Solar Inverters): Mitsubishi CM600DX-24T
Typically, there’s a trade-off: a low VCE(sat) often comes at the cost of higher switching losses. However, the datasheet for the CM600DX-24T defies this convention. Its total switching energy (Ets) at 150°C is a mere 112.5 mJ, drastically lower than the FF600R12IP4’s 198 mJ. This is a significant engineering achievement by Mitsubishi, indicating a superior optimization of the chip design and potentially the integrated freewheeling diode. For a central solar inverter operating at 8-16 kHz to reduce the size of magnetic components, this lower switching loss is a massive advantage. It not only boosts efficiency but also dramatically reduces the thermal stress on the module at each switching cycle. For a more detailed exploration of this topic, refer to our article, IGBT Selection Beyond VCE(sat): A Guide for High-Frequency Designs.

Round 3: Thermal Management and Reliability

Power loss generates heat, and how effectively that heat is removed is paramount to the module’s reliability and lifespan. The key metric here is the junction-to-case thermal resistance, Rth(j-c).

Here, the Infineon FF600R12IP4 has a slight edge with an Rth(j-c) of 0.045 K/W compared to Mitsubishi’s 0.048 K/W. This indicates that the PrimePACK™ housing of the Infineon module offers a marginally more efficient thermal path from the silicon chip to the baseplate. While the difference seems small, in a high-power-density application, it could mean a few degrees lower junction temperature under the same load conditions, which can have an exponential impact on the module’s lifetime.

However, reliability isn’t just about thermal resistance. The Mitsubishi T-Series modules, including the CM600DX-24T, often feature advancements like improved solder compositions and internal construction designed to enhance thermal cycling capability. Both modules exhibit a robust short-circuit withstand time of 10 microseconds, providing a solid safety margin for the protection circuits to act in case of a fault. This level of robustness is essential for applications like solar inverters, which can be subject to grid-side disturbances.

The Verdict: An Application-Centric Choice

Based on this in-depth analysis, a clear winner emerges depending on the engineering priorities:

The Mitsubishi CM600DX-24T is the undisputed champion in terms of electrical performance. It offers significantly lower conduction losses and, surprisingly, dramatically lower switching losses. For any application where overall efficiency is the primary driver—such as a large-scale solar inverter or a high-performance EV charger—the CM600DX-24T will deliver superior results, leading to lower operating costs and reduced thermal management requirements.

The Infineon FF600R12IP4, while having higher losses in this specific comparison, remains a formidable competitor largely due to its packaging and thermal design. Its slightly better Rth(j-c) and the widespread industry familiarity with the PrimePACK™ could make it a preferred choice in designs where the thermal system is highly constrained or where existing mechanical designs are built around Infineon’s package. It’s a testament to robust, conservative engineering.

It’s also worth noting that other manufacturers like Semikron offer competing modules such as the SKM600GB12M7, which presents another set of trade-offs, often excelling in areas like power cycling lifetime due to proprietary technologies like sintering. A thorough design process should always consider at least three viable options.

Final Recommendation & Call to Action

For the senior engineer designing a next-generation, high-efficiency 350kW solar inverter, the data points overwhelmingly in favor of the Mitsubishi CM600DX-24T. Its superior loss characteristics across both conduction and switching domains promise a system that is more efficient, runs cooler, and ultimately delivers a better return on investment. The minor disadvantage in Rth(j-c) is more than compensated for by the substantially lower heat generation in the first place.

Choosing the right power module is more than a component selection; it’s a critical system architecture decision. Are you ready to optimize your next high-power project? Explore the detailed specifications of the CM600DX-24T on our product page or contact our team of application engineers to discuss your specific design challenges and run a personalized loss simulation.