7-Pin SiC MOSFETs

ROHM Semiconductor extends its portfolio of discrete silicon carbide (SiC) MOSFETs with devices now available in the TO-263-7L SMD package. The benefit of the Kelvin connection to the source terminal of the SiC MOSFET provided by the TO-263-7L package is illustrated in the image below. The main source-inductance (L_S) is no longer shared by the gate-drive loop and the main current path. As a result, the device can be switched faster, which leads to reduced switching losses.

The TO-263-7L SMD Package and Its Parasitic Inductances

At turn-on, the three-lead device is limited in switching speed because the inductive voltage drop across the source terminal reduces the effective gate voltage leading to a long di/dt transition time and significant turn-on losses. This period is shorter in a device in the SMD package with Kelvin source connection to the gate driver and, hence, the turn-on loss is reduced. Similarly, a much higher di/dt speed can be achieved in the turn-off transient due to the reduced parasitic inductance effect in the TO263-7L package, resulting in lower turn-off loss than the TO-247 package.

While SiC MOSFETs can achieve very high switching speeds, which significantly reduce the energy loss in power electronic converters, the devices' full potential cannot always be used due to limitations of the traditional power semiconductor packages. This updated packaging from ROHM aims to remove that limitation.