Low ON-resistance and high-power MOSFETs for high-performance enterprise and AI servers

ROHM has developed N-channel power MOSFETs with 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 raised the demand for data centre servers. At the same time, the number of servers furnished 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, seven days a week – ensuring continuous operation. As a result, conduction losses created by the ON-resistance of multiple MOSFETs in the power block greatly impact 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 necessity for low ON-resistance MOSFETs. 

Also, servers equipped with a standard hot-swap function, which allows for replacing and maintaining internal boards and storage devices while powered ON, experience a high inrush current during component exchanges. A wide SOA tolerance is essential to protect server components and MOSFETs from damage. 

To manage these challenges, the company has developed its new DFN5060-8S package, which supports the packaging of a larger die compared to conventional designs. This results in a lineup of power MOSFETs that achieve industry-leading low ON-resistance together with wide SOA capability. These new products greatly enhance efficiency and reliability in server power circuits. 

The new lineup includes three products. The RS7E200BG (30V) is optimised for 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 (5mm × 6mm). The package increases the internal die size area by approximately 65% compared to the traditional HSOP8 package (5mm × 6mm). As a result, the RS7E200BG (30V) and RS7N200BH (80V) achieve ON-resistances of 0.53mOhm and 1.7mOhm (at VGS = 10V), respectively – both of which rank among the best in the industry in the 5mm × 6mm class, greatly contributing to higher efficiency in server power circuits. 

Moreover, the company has optimised the internal clip design to improve heat dissipation, further enhancing SOA tolerance and providing application reliability. Notably, the RS7E200BG (30V) achieves an SOA tolerance of over 70A at a pulse width of 1ms and VDS = 12V, which is twice that of the traditional HSOP8 package MOSFETs under the same conditions, ensuring industry-leading SOA performance in a 5mm × 6mm footprint.