1200 V, 30 A fast recovery diode for high-voltage switching
The STMicroelectronics STTH30S12W is a fast recovery epitaxial diode rated for 1200 V reverse voltage and 30 A average forward current, packaged in a through-hole DO-247-2 with straight leads. Its 50 ns reverse recovery time places it in the fast-recovery class for hard-switching topologies where stored charge recovery losses matter.
The 50 ns reverse recovery time is the headline switching parameter. In a continuous-current-mode boost PFC or a hard-switched inverter leg, this trr determines the reverse-recovery charge that the companion IGBT or MOSFET must commutate. A 50 ns trr at 30 A keeps the recovery losses manageable at switching frequencies up to the tens of kilohertz range typical of industrial power stages. The 2.9 V forward drop at 30 A is the conduction-loss counterpart — at full load expect roughly 87 W forward dissipation, which drives the heatsink sizing. The 15 µA leakage at 1200 V rated voltage confirms the blocking junction quality; leakage doubles roughly every 10°C above 25°C junction, so at 125°C junction count on about 240 µA, still negligible for most designs.
DO-247 through-hole — mounting and thermal interface
The DO-247-2 package with straight leads is a standard through-hole power package. The metal tab is the anode connection and provides the primary thermal path — plan for a heatsink with a TO-247/DO-247 compatible clip or screw mount. The straight lead form suits vertical PCB mounting; if your board uses a right-angle or surface-mount power layout, check whether a formed-lead variant or a different package in the STTH30 family fits better. The package is rated for the full 175°C junction temperature, so the thermal interface material and heatsink must keep the case temperature within the derating curve.
The base product number STTH30 covers a family of 30 A diodes at various voltage ratings and package options; if your board layout or voltage requirement shifts, the same base number lets you move within the family without requalifying the footprint.