ROHM Develops Class-Leading Low ON-Resistance, High-Power MOSFETs for High-Performance Enterprise and AI Servers

­ROHM Semiconductor has developed N-channel power MOSFETs featuring industry-leading low ON-resistance and wide SOA capability. They are designed for power supplies inside high-performance enterprise and AI servers.

The advancement of high-level data processing technologies and the acceleration of digital transformation have increased the demand for data center servers. At the same time, the number of servers equipped with advanced computing capabilities for AI processing is on the rise and is expected to continue to grow. These servers operate 24 hours a day, 7 days a week – ensuring continuous operation. As a result, conduction losses caused by the ON-resistance of multiple MOSFETs in the power block have a significant impact on system performance and energy efficiency. This becomes particularly evident in AC-DC conversion circuits, where conduction losses make up a substantial portion of total power loss – driving the need for low ON-resistance MOSFETs.

Additionally, servers equipped with a standard hot-swap function, which allow for the replacement and maintenance of internal boards and storage devices while powered ON, experience a high inrush current during component exchanges. Therefore, to protect server components and MOSFETs from damage, a wide Safe Operating Area (SOA) tolerance is essential.

To address these challenges, ROHM has developed its new DFN5060-8S package that supports the packaging of a larger die compared to conventional designs, resulting in a lineup of power MOSFETs that achieve industry-leading* low ON-resistance along with wide SOA capability. These new products significantly contribute to improving efficiency and enhancing reliability in server power circuits.

The new lineup includes three products. The RS7E200BG (30V) is optimized for both secondary-side AC-DC conversion circuits and hot-swap controller (HSC) circuits in 12V power supplies used in high-performance enterprise servers. The RS7N200BH (80V) and RS7N160BH (80V) are ideal for secondary AC-DC conversion circuits in 48V AI server power supplies.

All three models feature the newly developed DFN5060-8S package (5.0mm × 6.0mm). The package increases the internal die size area by approximately 65% compared to the conventional HSOP8 package (5.0mm × 6.0mm). As a result, the RS7E200BG (30V) and RS7N200BH (80V) achieve ON-resistances of 0.53mΩ and 1.7mΩ (at V_GS = 10V), respectively – both of which rank among the best in the industry in the 5.0mm × 6.0mm class, significantly contributing to higher efficiency in server power circuits.

Moreover, ROHM has optimized the internal clip design to enhance heat dissipation, further improving SOA tolerance, which contributes to ensuring application reliability. Notably, the RS7E200BG (30V) achieves an SOA tolerance of over 70A at a pulse width of 1ms and V_DS = 12V, which is twice that of the conventional HSOP8 package MOSFETs under the same conditions, ensuring industry-leading SOA performance in a 5.0mm × 6.0mm footprint.

Going forward, ROHM plans to gradually begin mass production of power MOSFETs compatible with hot-swap controller circuits for AI servers in 2025, continuing to expand its lineup that contributes to greater efficiency and reliability across a wide range of applications.

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