1000 V, 30 A fast recovery — where it lands in the power stage
The STTH3010PI is a 1000 V, 30 A fast recovery epitaxial diode from STMicroelectronics, built for the output rectification stage of high-voltage switched-mode power supplies, PFC boost stages, and industrial motor-drive DC links. The 100 ns reverse recovery time (trr) at 30 A forward current is the spec that decides whether this diode handles the switching frequency without excessive turn-off loss — it is fast enough for hard-switching PFC running 50–100 kHz, but not intended for the sub-50 ns trr demands of 200 kHz+ resonant converters. The insulated DOP3I-2 package means the metal tab is electrically isolated — you bolt it directly to a grounded heatsink without a mica insulator or thermal pad. That saves assembly time and improves thermal transfer versus a standard TO-247 with an isolation washer.
Conduction loss and thermal budget at 30 A
At 30 A forward current the maximum forward voltage is 2 V, which puts conduction loss at 60 W. That is the number the heatsink design starts from. Reverse leakage at the full 1000 V blocking voltage is 15 µA at 25°C. That figure climbs with junction temperature — expect it to multiply roughly 10× at 125°C. For standby-power-sensitive designs, the leakage at high temperature needs to be factored into the bias supply budget.
Package and mounting — the insulated tab advantage
The DOP3I-2 is a through-hole package with straight leads and an insulated metal tab. Through-hole mounting handles the mechanical leverage of a bolt-on heatsink better than a surface-mount D2PAK, which can crack solder joints under thermal cycling if the heatsink is heavy.